Information technology (IT) is the design, development, implementation, support, and management of computer hardware and software applications. An IT professional is knowledgeable about computer systems and operating systems. This chapter will review IT certifications and the components of a basic personal computer system.
After completing this chapter, you will meet these objectives:
Explain IT industry certifications.
Describe a computer system.
Identify the names, purposes, and characteristics of cases and power supplies.
Identify the names, purposes, and characteristics of internal components.
Identify the names, purposes, and characteristics of ports and cables.
Identify the names, purposes, and characteristics of input devices.
Identify the names, purposes, and characteristics of output devices.
Explain system resources and their purposes.
This course will focus on desktop and laptop computers. It will also discuss electronic devices, such as personal digital assistants and cell phones.
Training and experience will qualify a technician to service these computers and personal electronic devices. You will gain the specialized technical skills needed to install, maintain, and repair computers. Earning an industry-standard certification will give you confidence and increase your opportunities in IT.
This course is focused on the following two industry-standard certifications:
CompTIA A+
European Certification of Informatics Professional (EUCIP) IT Administrator Certification (Modules 1 and 2)
After completing this section, you will meet these objectives:
Identify education and certifications.
Describe the A+ Certification.
Describe the EUCIP Certification.
Information Technology (IT) is a term that encompasses the relationship between hardware, software, networks, and technical assistance provided to users. IT Essentials: PC Hardware and Software covers the information that a technician needs to be successful in IT. This course covers the following topics:
Personal computers
Safe lab procedures
Troubleshooting
Operating systems
Laptop computers
Printers and scanners
Networks
Security
Communication skills
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The IT Essentials course focuses on two hardware and software skills-based industry certifications: CompTIA A+ and EUCIP. This course is only an introduction into the world of IT. A technician may continue to study and earn the following certifications:
CCNA – Cisco Certified Networking Associate
CCNP – Cisco Certified Networking Professional
CCIE – Cisco Certified Internetworking Expert
CISSP – Certified Information Systems Security Professional
MCP – Microsoft Certified Professional
MCSA – Microsoft Certified Systems Administrator
MCSE – Microsoft Certified Systems Engineer
Network+ – CompTIA Network Certification
Linux+ – CompTIA Linux Certification
IT certifications can be used as credits for university and college degrees in areas such as computer science and telecommunications.
Computing Technology Industry Association (CompTIA) developed the A+ Certification program. A CompTIA A+ certification, as shown in Figure 1, signifies that a candidate is a qualified PC hardware and software technician. CompTIA certifications are known throughout the IT community as one of the best ways to enter the information technology field and build a solid career.
The latest version of CompTIA A+ is CompTIA A+ 2009 Edition. Two exams are necessary to be certified: CompTIA A+ Essentials, exam code 220-701; and CompTIA A+ Practical Application, exam code 220-702.
CompTIA A+ Essentials measures the necessary competencies of an entry-level IT professional with at least 500 hours of hands-on experience in the lab or field. It tests for the fundamentals of computer technology, networking and security, as well as the communication skills and professionalism now required of all entry-level IT professionals.
CompTIA A+ Practical Application is an extension of the knowledge and skills identified in CompTIA A+ Essentials, with more of a hands-on orientation focused on scenarios in which troubleshooting and tools must be applied to resolve problems.
The EUCIP IT Administrator program offers a recognized certification of competence in IT. The certification covers the standards prescribed by the Council of European Professional Informatics Societies (CEPIS). The EUCIP IT Administrator Certification consists of five modules, with a corresponding exam for each module. This course will prepare you for Modules 1 and 2.
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Module 1: PC Hardware
The PC Hardware module requires that the candidate understand the basic makeup of a personal computer and the functions of the components. The candidate should be able to effectively diagnose and repair hardware problems. The candidate should be able to advise customers of the appropriate hardware to buy.
Module 2: Operating Systems
The Operating Systems module requires that the candidate be familiar with the procedures for installing and updating most common operating systems and applications. The candidate should know how to use system tools for troubleshooting and repairing operating systems.
Module 3: Local Area Network and Network Services
This module is beyond the scope of the IT Essentials course, although some of the topics are covered. The Local Area Network and Network Services module requires that the candidate be familiar with the procedure of installing, using, and managing local area networks. The candidate should be able to add and remove users and shared resources. The candidate should know how to use system tools for troubleshooting and repairing networks.
Module 4: Expert Network Use
This module is beyond the scope of the IT Essentials course, although some of the topics are covered. The Expert Network Use module requires that the candidate understand LAN communication.
Module 5: IT Security
This module is beyond the scope of the IT Essentials course, although some of the topics are covered. The IT Security module requires that the candidate be familiar with security methods and features that are available for a standalone or networked computer.
A computer system consists of hardware and software components. Hardware is the physical equipment such as the case, storage drives, keyboards, monitors, cables, speakers, and printers. The term software includes the operating system and programs. The operating system instructs the computer how to operate. These operations may include identifying, accessing, and processing information. Programs or applications perform different functions. Programs vary widely depending on the type of information that will be accessed or generated. For example, instructions for balancing a checkbook are very different from instructions for simulating a virtual reality world on the Internet.
The rest of this chapter discusses the hardware components found in a computer system.
The computer case provides protection and support for the internal components of the computer. All computers need a power supply to convert alternating-current (AC) power from the wall socket into direct-current (DC) power. The size and shape of the computer case is usually determined by the motherboard and other internal components.
You can select a large computer case to accommodate additional components that may be required in the future. Other users may select a smaller case that requires minimal space. In general, the computer case should be durable, easy to service, and have enough room for expansion.
The power supply must provide enough power for the components that are currently installed and allow for additional components that may be added at a later time. If you choose a power supply that powers only the current components, it may be necessary to replace the power supply when other components are upgraded.
After completing this section, you will meet these objectives:
Describe cases.
Describe power supplies.
A computer case contains the framework to support the internal components of a computer while providing an enclosure for added protection. Computer cases are typically made of plastic, steel, and aluminum and are available in a variety of styles.
The size and layout of a case is called a form factor. There are many types of cases, but the basic form factors for computer cases include desktop and tower. Desktop cases may be slimline or full-sized, and tower cases may be mini or full-sized, as shown in Figure 1.
Computer cases are referred to in a number of ways:
Computer chassis
Cabinet
Tower
Box
Housing
In addition to providing protection and support, cases also provide an environment designed to keep the internal components cool. Case fans are used to move air through the computer case. As the air passes warm components, it absorbs heat and then exits the case. This process keeps the components of the computer from overheating.
There are many factors that must be considered when choosing a case:
The size of the motherboard
The number of external or internal drive locations called bays
Available space
See Figure 2 for a list of features.
In addition to providing protection from the environment, cases help to prevent damage from static electricity. Internal components of the computer are grounded by attachment to the case.
NOTE: You should select a case that matches the physical dimensions of the power supply and motherboard.
The power supply, shown in Figure 1, converts alternating-current (AC) power coming from a wall outlet into direct-current (DC) power, which is a lower voltage. DC power is required for all of the components inside the computer.
A computer can tolerate slight fluctuations in power, but a significant deviation can cause the power supply to fail. An uninterruptible power supply (UPS) can protect a computer from problems caused by changes in power. A UPS provides power for a computer using a power inverter. A power inverter provides AC power to the computer from a built-in battery by converting the DC current of the UPS battery into AC power.
Connectors
Most connectors today are keyed connectors. Keyed connectors are designed to be inserted in only one direction. Each part of the connector has a colored wire with a different voltage running through it, as seen in Figure 2. Different connectors are used to connect specific components to various ports on the motherboard:
A Molex connector is a keyed connector used to connect to an optical drive or a hard drive.
A Berg connector is a keyed connector used to connect to a floppy drive. A Berg connector is smaller than a Molex connector.
A 20-pin or 24-pin slotted connector is used to connect to the motherboard. The 24-pin slotted connector has two rows of 12 pins each, and the 20-pin slotted connector has two rows of 10 pins each.
A 4-pin to 8-pin auxiliary power connector has two rows of two to four pins and supplies power to all areas of the motherboard. The 4-pin to 8-pin auxiliary power connector is the same shape as the main power connector, but smaller.
Older standard power supplies used two connectors called P8 and P9 to connect to the motherboard. P8 and P9 were unkeyed connectors. They could be installed backwards, potentially damaging the motherboard or power supply. The installation required that the connectors were lined up with the black wires together in the middle.
NOTE: If you have a difficult time inserting a connector, try a different way, or check to make sure that there are no bent pins or foreign objects in the way. Remember, if it seems difficult to plug in any cable or other part, something is wrong. Cables, connectors, and components are designed to fit together snugly. Never force any connector or component. The connectors that are plugged in incorrectly will damage the plug and the connector. Take your time and make sure that you are handling the hardware correctly.
Electricity and Ohm's Law
These are the four basic units of electricity:
Voltage (V)
Current (I)
Power (P)
Resistance (R)
Voltage, current, power, and resistance are electronic terms that a computer technician must know:
Voltage is a measure of the force required to push electrons through a circuit.
Voltage is measured in volts (V). A computer power supply usually produces several different voltages.
Current is a measure of the amount of electrons going through a circuit.
Current is measured in amperes, or amps (A). Computer power supplies deliver different amperages for each output voltage.
Power is a measure of the pressure required to push electrons through a circuit, called voltage, multiplied by the number of electrons going through that circuit, called current. The measurement is called watts (W). Computer power supplies are rated in watts.
Resistance is the opposition to the flow of current in a circuit. Resistance is measured in ohms. Lower resistance allows more current, and therefore more power, to flow through a circuit. A good fuse will have low resistance or a measurement of almost 0 ohms.
There is a basic equation that expresses how three of the terms relate to each other. It states that voltage is equal to the current multiplied by the resistance. This is known as Ohm's Law.
V = IR
In an electrical system, power (P) is equal to the voltage multiplied by the current.
P = VI
In an electrical circuit, increasing the current or the voltage will result in higher power.
As an example of how this works, imagine a simple circuit that has a 9V light bulb hooked up to a 9V battery. The power output of the light bulb is 100W. Using the equation above, we can calculate how much current in amps would be required to get 100W out of this 9V bulb.
To solve this equation, we know the following information:
P = 100W
V = 9V
I = 100W / 9V = 11.11A
What happens if a 12V battery and a 12V light bulb are used to get 100W of power?
100W / 12V = 8.33A
This system produces the same power, but with less current.
Computers normally use power supplies ranging from 250W to 650W output capacity. However, some computers may need 850W and higher capacity power supplies. When building a computer, select a power supply with sufficient wattage to power all of the components. Each component inside the computer uses a certain amount of power. Obtain the wattage information for the components from the manufacturer's documentation. When deciding on a power supply, make sure to choose a power supply that has more than enough power for the current components. A power supply with a higher wattage rating has more capacity; therefore, it can handle more devices.
On the back of the power supply is a small switch called the voltage selector switch. This switch sets the input voltage to the power supply to either 110V / 115V or 220V / 230V. The correct voltage setting is determined by the country where the power supply will be used. Setting the voltage switch to the incorrect input voltage could damage the power supply and other parts of your computer. If a power supply does not have the voltage selector switch, your power supply will automatically detect and set the correct voltage.
CAUTION: Do not open a power supply. Electronic capacitors located inside of a power supply, shown in Figure 3, can hold a charge for extended periods of time.
This section discusses the names, purposes, and characteristics of the internal components of a computer.
After completing this section, you will meet these objectives:
Identify the names, purposes, and characteristics of motherboards.
Explain the names, purposes, and characteristics of CPUs.
Identify the names, purposes, and characteristics of cooling systems.
Identify the names, purposes, and characteristics of ROM and RAM.
Identify the names, purposes, and characteristics of adapter cards.
Identify the names, purposes, and characteristics of storage drives.
Identify the names, purposes, and characteristics of internal cables.
The motherboard is the main printed circuit board and contains the buses, or electrical pathways, found in a computer. These buses allow data to travel between the various components that comprise a computer. Figure 1 shows a variety of motherboards. A motherboard is also known as the system board, the backplane, or the main board.
The motherboard accommodates the central processing unit (CPU), RAM, expansion slots, heat sink/fan assembly, BIOS chip, chipset, and the embedded wires that interconnect the motherboard components. Sockets, internal and external connectors, and various ports are also placed on the motherboard.
The form factor of motherboards pertains to the size and shape of the board. It also describes the physical layout of the different components and devices on the motherboard. The form factor determines how individual components attach to the motherboard and the shape of the computer case. Various form factors exist for motherboards, as shown in Figure 2.
The most common form factor in desktop computers was the AT, based on the IBM AT motherboard. The AT motherboard can be up to approximately one foot wide. This cumbersome size led to the development of smaller form factors. The placement of heat sinks and fans often interferes with the use of expansion slots in smaller form factors.
A newer motherboard form factor, ATX, improved on the AT design. The ATX case is designed to accommodate the integrated I/O ports on the ATX motherboard. The ATX power supply connects to the motherboard via a single 20-pin connector instead of the confusing P8 and P9 connectors used with some earlier form factors. Instead of using a physical toggle switch, the ATX power supply can be powered on and off using signaling from the motherboard.
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Some manufacturers have proprietary form factors based on the ATX design. This causes some motherboards, power supplies, and other components to be incompatible with standard ATX cases.
An important set of components on the motherboard is the chipset. The chipset is composed of various integrated circuits attached to the motherboard that control how system hardware interacts with the CPU and motherboard. The CPU is installed into a slot or socket on the motherboard. The socket on the motherboard determines the type of CPU that can be installed.
The chipset of a motherboard allows the CPU to communicate and interact with the other components of the computer, and to exchange data with system memory, or RAM, hard disk drives, video cards, and other output devices. The chipset establishes how much memory can be added to a motherboard. The chipset also determines the type of connectors on the motherboard.
Most chipsets are divided into two distinct components, Northbridge and Southbridge. What each component does varies from manufacturer to manufacturer. In general, the Northbridge controls access to the RAM, video card, and the speeds at which the CPU can communicate with them. The video card is sometimes integrated into the Northbridge. AMD and Intel have chips that integrate the memory controller onto the CPU die, which improves performance and power consumption. The Southbridge, in most cases, allows the CPU to communicate with the hard drives, sound card, USB ports, and other I/O ports.
The central processing unit (CPU) is considered the brain of the computer. It is sometimes referred to as the processor. Most calculations take place in the CPU. In terms of computing power, the CPU is the most important element of a computer system. CPUs come in different form factors, each style requiring a particular slot or socket on the motherboard. Common CPU manufacturers include Intel and AMD.
The CPU socket or slot is the connector that interfaces between the motherboard and the processor. Most CPU sockets and processors in use today are built around the pin grid array (PGA) architecture, in which the pins on the underside of the processor are inserted into the socket, usually with zero insertion force (ZIF). ZIF refers to the amount of force needed to install a CPU into the motherboard socket or slot. Slot-based processors are cartridge-shaped and fit into a slot that looks similar to an expansion slot. Figure 1 lists common CPU socket specifications.
The CPU executes a program, which is a sequence of stored instructions. Each model of processor has an instruction set, which it executes. The CPU executes the program by processing each piece of data as directed by the program and the instruction set. While the CPU is executing one step of the program, the remaining instructions and the data are stored nearby in a special memory called cache. There are two major CPU architectures related to instruction sets:
Reduced Instruction Set Computer (RISC) – Architectures use a relatively small set of instructions, and RISC chips are designed to execute these instructions very rapidly.
Complex Instruction Set Computer (CISC) – Architectures use a broad set of instructions, resulting in fewer steps per operation.
Some CPUs incorporate hyperthreading to enhance the performance of the CPU. With hyperthreading, the CPU has multiple pieces of code being executed simultaneously on each pipeline. To an operating system, a single CPU with hyperthreading performs as though there are two CPUs.
The power of a CPU is measured by the speed and the amount of data that it can process. The speed of a CPU is rated in cycles per second. The speed of current CPUs is measured in millions of cycles per second, called megahertz (MHz), or billions of cycles per second, called gigahertz (GHz). The amount of data that a CPU can process at one time depends on the size of the processor data bus. This is also called the CPU bus or the front side bus (FSB). The wider the processor data bus width, the more powerful the processor is. Current processors have a 32-bit or a 64-bit processor data bus.
Overclocking is a technique used to make a processor work at a faster speed than its original specification. Overclocking is not a reliable way to improve computer performance and can result in damage to the CPU. The opposite of overclocking is CPU throttling. CPU throttling is a technique used when the processor runs at less than the rated speed to conserve power or produce less heat. Throttling is commonly used on laptops and other mobile devices.
MMX is a set of multimedia instructions built into Intel processors. MMX enabled microprocessors can handle many common multimedia operations that are normally handled by a separate sound or video card. However, only software specifically written to call MMX instructions can use the MMX instruction set. In Intel CPUs, MMX has been replaced by Streaming Single-instruction-multi-data Extensions (SSE), which is an enhancement to the instruction set. There are many versions of SSE, each of which includes additional instructions.
The latest processor technology has resulted in CPU manufacturers finding ways to incorporate more than one CPU core onto a single chip. Figure 2 lists the most common multiple core processors. These CPUs are capable of processing multiple instructions concurrently:
Single Core CPU – One core inside a single CPU that handles all of the processing capability. A motherboard manufacturer may provide sockets for more than one single processor, providing the ability to build a powerful, multi-processor computer.
Dual Core CPU – Two cores inside a single CPU in which both cores can process information at the same time.
Triple Core CPU – Three cores inside a single CPU that is actually a quad-core processor with one of the cores disabled.
Quad Core CPU – Four cores inside a single CPU in which all cores can process information simultaneously for enhanced software applications.
Electronic components generate heat. Heat is caused by the flow of current within the components. Computer components perform better when kept cool. If the heat is not removed, the computer may run slower. If too much heat builds up, computer components can be damaged.
Increasing the air flow in the computer case allows more heat to be removed. A case fan, shown in Figure 1, is installed in the computer case to make the cooling process more efficient.
In addition to case fans, a heat sink draws heat away from the core of the CPU. A fan on top of the heat sink, shown in Figure 2, moves the heat away from the CPU.
Other components are also susceptible to heat damage and are sometimes equipped with fans. Video adapter cards also produce a great deal of heat. Fans are dedicated to cool the graphics-processing unit (GPU), as seen in Figure 3.
Computers with extremely fast CPUs and GPUs may use a water-cooling system. A metal plate is placed over the processor and water is pumped over the top to collect the heat that the CPU creates. The water is pumped to a radiator to be cooled by the air, and then re-circulated.
ROM
Read-only memory (ROM) chips are located on the motherboard. ROM chips contain instructions that can be directly accessed by the CPU. Basic instructions for booting the computer and loading the operating system are stored in ROM. ROM chips retain their contents even when the computer is powered down. The contents cannot be erased or changed by normal means. The different types of ROM are described in Figure 1.
NOTE: ROM is sometimes called firmware. This is misleading because firmware is actually the software that is stored in a ROM chip.
RAM
Random access memory (RAM) is the temporary storage for data and programs that are being accessed by the CPU. RAM is volatile memory, which means that the contents are erased when the computer is powered off. The more RAM in a computer, the more capacity the computer has to hold and process large programs and files, as well as enhance system performance. The different types of RAM are described in Figure 2.
Memory Modules
Early computers had RAM installed on the motherboard as individual chips. The individual memory chips, called dual inline package (DIP) chips, were difficult to install and often became loose on the motherboard. To solve this problem, designers soldered the memory chips on a special circuit board called a memory module. The different types of memory modules are described in Figure 3.
NOTE: Memory modules can be single-sided or double-sided. Single-sided memory modules only contain RAM on one side of the module. Double-sided memory modules contain RAM on both sides of the module.
The speed of memory has a direct impact on how much data a processor can process because faster memory improves the performance of the processor. As processor speed increases, memory speed must also increase. For example, single-channel memory is capable of transferring data at 64 bits. Dual-channel memory increases speed by using a second channel of memory, creating a data transfer rate of 128 bits.
Double Data Rate (DDR) technology doubles the maximum bandwidth of SDRAM. DDR2 offers faster performance while using less energy. DDR3 operates at even higher speeds than DDR2; however, none of these DDR technologies are backward- or forward-compatible. See Figure 4 for a chart comparing different memory types and speeds.
Cache
SRAM is used as cache memory to store the most frequently used data. SRAM provides the processor with faster access to the data than retrieving it from the slower DRAM, or main memory. The three types of cache memory are described in Figure 5.
Error Checking
Memory errors occur when the data is not stored correctly in the RAM chips. The computer uses different methods to detect and correct data errors in memory. Figure 6 describes three different methods of memory error checking.
Adapter cards increase the functionality of a computer by adding controllers for specific devices or by replacing malfunctioning ports. Figure 1 shows several types of adapter cards. Adapter cards are used to expand and customize the capability of the computer:
Network Interface Card (NIC) – Connects a computer to a network using a network cable
Wireless NIC – Connects a computer to a network using radio frequencies
Sound adapter – Provides audio capability
Video adapter – Provides graphic capability
Capture card – Sends a video signal to a computer so that the signal can be recorded to the computer hard drive with Video Capture software
TV tuner – Provides the ability to watch and record TV signals on a PC by connecting a TV source, such as cable TV, satellite, or an antenna, to the installed tuner card
Modem adapter – Connects a computer to the Internet using a phone line
Small Computer System Interface (SCSI) adapter – Connects SCSI devices, such as hard drives or tape drives, to a computer
Redundant Array of Independent Disks (RAID) adapter – Connects multiple hard drives to a computer to provide redundancy and to improve performance
Universal Serial Bus (USB) port – Connects a computer to peripheral devices
Parallel port – Connects a computer to peripheral devices
Serial port – Connects a computer to peripheral devices
Computers have expansion slots on the motherboard to install adapter cards. The type of adapter card connector must match the expansion slot. A riser card was used in computer systems with the LPX form factor to allow adapter cards to be installed horizontally. The riser card was mainly used in slim-line desktop computers. The different types of expansion slots are shown in Figure 2.
Storage drives, as shown in Figure 1, read or write information to magnetic or optical storage media. The drive can be used to store data permanently or to retrieve information from a media disk. Storage drives can be installed inside the computer case, such as a hard drive. For portability, some storage drives can connect to the computer using a USB port, a FireWire port, or an SCSI port. These portable storage drives are sometimes referred to as removable drives and can be used on multiple computers. Here are some common types of storage drives:
Floppy drive
Hard drive
Optical drive
Flash drive
Floppy Drive
A floppy drive, or floppy disk drive, is a storage device that uses removable 3.5-inch floppy disks. These magnetic floppy disks can store 720 KB or 1.44 MB of data. In a computer, the floppy drive is usually configured as the A: drive. The floppy drive can be used to boot the computer if it contains a bootable floppy disk. A 5.25-inch floppy drive is older technology and is seldom used.
Hard Drive
A hard drive, or hard disk drive, is a magnetic storage device that is installed inside the computer. The hard drive is used as permanent storage for data. In a Windows computer, the hard drive is usually configured as the C: drive and contains the operating system and applications. The hard drive is often configured as the first drive in the boot sequence. The storage capacity of a hard drive is measured in billions of bytes, or gigabytes (GB). The speed of a hard drive is measured in revolutions per minute (RPM). Multiple hard drives can be added to increase storage capacity.
Traditional hard drives are magnetic. Magnetic hard drives have drive motors designed to spin magnetic platters and the drive heads. In contrast, the newer solid state drives (SSDs) do not have moving parts. Because there are no drive motors and moving parts, the SSD uses far less energy than the magnetic hard drive. Non-volatile flash memory chips manage all storage on an SSD, which results in faster access to data, higher reliability, and reduced power usage. SSDs have the same form factor as magnetic hard drives and use ATA or SATA interfaces. SSDs can be installed as a replacement for magnetic drives.
Optical Drive
An optical drive is a storage device that uses lasers to read data on the optical media. There are three types of optical drives:
Compact Disc (CD)
Digital versatile Disc (DVD)
Blu-ray Disc (BD)
CD, DVD, and BD media can be pre-recorded (read-only), recordable (write once), or re-recordable (read and write multiple times). CDs have a data storage capacity of approximately 700 MB. DVDs have a data storage capacity of approximately 4.3 GB on a single-layer disc, and approximately 8.5 GB on a dual-layer disc. BDs have a storage capacity of 25 GB on a single-layer disc, and 50 GB on a dual-layer disc.
There are several types of optical media:
CD-ROM – CD read-only memory media that is pre-recorded.
CD-R – CD recordable media that can be recorded one time.
CD-RW – CD rewritable media that can be recorded, erased, and re-recorded.
DVD-ROM – DVD read-only memory media that is pre-recorded.
DVD-RAM – DVD random access memory media that can be recorded, erased, and re-recorded.
DVD+/-R – DVD recordable media that can be recorded one time.
DVD+/-RW – DVD rewritable media that can be recorded, erased, and re-recorded.
BD-ROM – BD read-only media that is pre-recorded with movies, games, or software.
BD-R – BD recordable media that can record HD video and PC data storage one time.
BD-RE – BD rewritable format for HD video recording and PC data storage.
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External Flash Drive
An external flash drive, also known as a thumb drive, is a removable storage device that connects to a USB port. An external flash drive uses the same type of non-volatile memory chips as solid state drives and does not require power to maintain the data. These drives can be accessed by the operating system in the same way that other types of drives are accessed.
Types of Drive Interfaces
Hard drives and optical drives are manufactured with different interfaces that are used to connect the drive to the computer. To install a storage drive in a computer, the connection interface on the drive must be the same as the controller on the motherboard. Here are some common drive interfaces:
IDE – Integrated Drive Electronics, also called Advanced Technology Attachment (ATA) is an early drive controller interface that connects computers and hard disk drives. An IDE interface uses a 40-pin connector.
EIDE – Enhanced Integrated Drive Electronics, also called ATA-2, is an updated version of the IDE drive controller interface. EIDE supports hard drives larger than 512 MB, enables Direct Memory Access (DMA) for speed, and uses the AT Attachment Packet Interface (ATAPI) to accommodate optical drives and tape drives on the EIDE bus. An EIDE interface uses a 40-pin connector.
PATA – Parallel ATA refers to the parallel version of the ATA drive controller interface.
SATA – Serial ATA refers to the serial version of the ATA drive controller interface. A SATA interface uses a 7-pin data connector.
eSATA – External Serial ATA provides a hot-swappable, external interface for SATA drives. The eSATA interface connects an external SATA drive using a 7-pin connector. The cable can be up to two meters (6.56 ft.) in length.
SCSI – Small Computer System Interface is a drive controller interface that can connect up to 15 drives. SCSI can connect both internal and external drives. An SCSI interface uses a 50-pin, 68-pin, or 80-pin connector.
RAID provides a way to store data across multiple hard disks for redundancy. To the operating system, RAID appears as one logical disk. See Figure 2 for a comparison of the different RAID levels. The following terms describe how RAID stores data on the various disks:
Parity – A method used to detect data errors.
Striping – A method used to write data across multiple drives.
Mirroring – A method of storing duplicate data to a second drive.
Drives require both a power cable and a data cable. A power supply will have a SATA power connector for SATA drives, a Molex power connector for PATA drives, and a Berg 4-pin connector for floppy drives. The buttons and the LED lights on the front of the case connect to the motherboard with the front panel cables.
Data cables connect drives to the drive controller, which is located on an adapter card or on the motherboard. Here are some common types of data cables:
Floppy disk drive (FDD) data cable – Data cable has up to two 34-pin drive connectors and one 34-pin connector for the drive controller.
PATA (IDE/EIDE) 40-conductor data cable – Originally, the IDE interface supported two devices on a single controller. With the introduction of Extended IDE, two controllers capable of supporting two devices each were introduced. The 40-conductor ribbon cable uses 40-pin connectors. The cable has two connectors for the drives and one connector for the controller.
PATA (EIDE) 80-conductor data cable – As the data rates available over the EIDE interface increased, the chance of data corruption during transmission increased. An 80-conductor cable was introduced for devices transmitting at 33.3 MB/s and over, allowing for a more reliable balanced data transmission. The 80-conductor cable uses 40-pin connectors.
SATA data cable – This cable has seven conductors, one keyed connector for the drive, and one keyed connector the drive controller.
eSATA data cable – The eSATA external disk connects to the eSATA interface using a 7-pin data cable. This cable does not supply any power to the eSATA external disk. A separate power cable provides power to the disk.
SCSI data cable – There are three types of SCSI data cables. A narrow SCSI data cable has 50 conductors, up to seven 50-pin connectors for drives, and one 50-pin connector for the drive controller, also called the host adapter. A wide SCSI data cable has 68 conductors, up to 15 68-pin connectors for drives, and one 68-pin connector for the host adapter. An Alt-4 SCSI data cable has 80 conductors, up to 15 80-pin connectors for drives, and one 80-pin connector for the host adapter.
NOTE: A colored stripe on a cable identifies Pin 1 on the cable. When installing a data cable, always ensure that Pin 1 on the cable aligns with Pin 1 on the drive or drive controller. Some cables may be keyed and therefore they can only be connected one way to the drive and drive controller.
Input/output (I/O) ports on a computer connect peripheral devices, such as printers, scanners, and portable drives. The following ports and cables are commonly used:
Serial
USB
FireWire
Parallel
SCSI
Network
PS/2
Audio
Video
Serial Ports and Cables
A serial port can be either a DB-9, as shown in Figure 1, or a DB-25 male connector. Serial ports transmit one bit of data at a time. To connect a serial device, such as a modem or printer, a serial cable must be used. A serial cable has a maximum length of 50 feet (15.2 m).
Modem Ports and Cables
In addition to the serial cable used to connect an external modem to a computer, a telephone cable is used to connect a modem to a telephone outlet. This cable uses an RJ-11 connector, as shown in Figure 2. A traditional setup of an external modem using a serial cable and a telephone cable is shown in Figure 3.
USB Ports and Cables
The Universal Serial Bus (USB) is a standard interface that connects peripheral devices to a computer. It was originally designed to replace serial and parallel connections. USB devices are hot-swappable, which means that users can connect and disconnect the devices while the computer is powered on. USB connections can be found on computers, cameras, printers, scanners, storage devices, and many other electronic devices. A USB hub is used to connect multiple USB devices. A single USB port in a computer can support up to 127 separate devices with the use of multiple USB hubs. Some devices can also be powered through the USB port, eliminating the need for an external power source. Figure 4 shows USB cables with connectors.
USB 1.1 allowed transmission rates of up to 12 Mbps in full-speed mode and 1.5 Mbps in low-speed mode. USB 2.0 allows transmission speeds up to 480 Mbps. USB devices can only transfer data up to the maximum speed allowed by the specific port.
FireWire Ports and Cables
FireWire is a high-speed, hot-swappable interface that connects peripheral devices to a computer. A single FireWire port in a computer can support up to 63 devices. Some devices can also be powered through the FireWire port, eliminating the need for an external power source. FireWire uses the IEEE 1394 standard and is also known as i.Link.
The IEEE 1394a standard supports data rates up to 400 Mbps and cable lengths up to 15 feet (4.5 m). This standard uses a 6-pin connector or a 4-pin connector. The IEEE 1394b standard allows for a greater range of connections, including CAT5 UTP and optical fiber. Depending on the media used, data rates are supported up to 3.2 Gbps over a 100m distance. Figure 5 shows FireWire cables with connectors.
Parallel Ports and Cables
A parallel port on a computer is a standard Type A DB-25 female connector. The parallel connector on a printer is a standard Type B 36-pin Centronics connector. Some newer printers may use a Type C high-density 36-pin connector. Parallel ports can transmit 8 bits of data at one time and use the IEEE 1284 standard. To connect a parallel device, such as a printer, a parallel cable must be used. A parallel cable, as shown in Figure 6, has a maximum length of 15 feet (4.5 m).
SCSI Ports and Cables
A SCSI port can transmit parallel data at rates in excess of 320 MBps and can support up to 15 devices. If a single SCSI device is connected to an SCSI port, the cable can be up to 80 feet (24.4 m) in length. If multiple SCSI devices are connected to an SCSI port, the cable can be up to 40 (12.2 m) feet in length. An SCSI port on a computer can be one of three different types, as shown in Figure 7:
80-pin connector
50-pin connector
68-pin connector
NOTE: SCSI devices must be terminated at the endpoints of the SCSI chain. Check the device manual for termination procedures.
CAUTION: Some SCSI connectors resemble parallel connectors. Be careful not to connect the cable to the wrong port. The voltage used in the SCSI format may damage the parallel interface. SCSI connectors should be clearly labeled.
Network Ports and Cables
A network port, also known as an RJ-45 port, connects a computer to a network. The connection speed depends on the type of network port. Standard Ethernet can transmit up to 10 Mbps, Fast Ethernet can transmit up to 100 Mbps, and Gigabit Ethernet can transmit up to 1000 Mbps. The maximum length of network cable is 328 feet (100 m). A network connector is shown in Figure 8.
PS/2 Ports
A PS/2 port connects a keyboard or a mouse to a computer. The PS/2 port is a 6-pin mini-DIN female connector. The connectors for the keyboard and mouse are often colored differently, as shown in Figure 9. If the ports are not color-coded, look for a small figure of a mouse or keyboard next to each port.
Audio Ports
An audio port connects audio devices to the computer. Some of the following audio ports are commonly used, as shown in Figure 10:
Line In – Connects to an external source, such as a stereo system
Microphone – Connects to a microphone
Line Out – Connects to speakers or headphones
Sony/Philips Digital Interface Format (S/PDIF) – Connects to fiber optic cable to support digital audio
TosLink – Connects to coaxial cable to support digital audio
Gameport/MIDI – Connects to a joystick or MIDI-interfaced device
Video Ports and Connectors
A video port connects a monitor cable to a computer. Figure 11 shows three common video ports. There are several video port and connector types:
Video Graphics Array (VGA) – VGA has a 3-row, 15-pin female connector and provides analog output to a monitor.
Digital Visual Interface (DVI) – DVI has a 24-pin female connector or a 29-pin female connector and provides an uncompressed digital output to a monitor. DVI-I provides both analog and digital signals. DVI-D provides digital signals only.
High-Definition Multimedia Interface (HDMi) – HDMi has a 19-pin connector and provides digital video and digital audio signals.
S-Video – S-Video has a 4-pin connector and provides analog video signals.
Component/RGB – RGB has three shielded cables (red, green, blue) with RCA jacks and provides analog video signals.
An input device is used to enter data or instructions into a computer. Here are some examples of input devices:
Mouse and keyboard
Digital camera and digital video camera
Biometric authentication device
Touch screen
Scanner
The mouse and keyboard are the two most commonly used input devices. The mouse is used to navigate the graphical user interface (GUI). The keyboard is used to enter text commands that control the computer.
A keyboard, video, mouse (KVM) switch is a hardware device that can be used to control more than one computer using a single keyboard, monitor, and mouse. KVM switches provide cost-efficient access to multiple servers using a single keyboard, monitor, and mouse for businesses. Home users can save space using a KVM switch to connect multiple computers to one keyboard, monitor, and mouse. See Figure 1.
Newer KVM switches have added the capability to share USB devices and speakers with multiple computers. Typically, by pressing a button on the KVM switch, the user can change the control from one connected computer to another connected computer. Some models of the switch transfer control from one computer to another computer using a specific key sequence on a keyboard, such as CNTL > CNTL > A > ENTER to control the first computer connected to the switch, then CNTL > CNTL > B > ENTER to transfer control to the next computer.
Digital cameras and digital video cameras, shown in Figure 2, create images that can be stored on magnetic media. The image is stored as a file that can be displayed, printed, or altered.
Biometric identification makes use of features that are unique to an individual user, such as fingerprints, voice recognition, or a retinal scan. When combined with ordinary usernames, biometrics guarantees that the authorized person is accessing the data. Figure 3 shows a laptop that has a built-in fingerprint scanner. By measuring the physical characteristics of the fingerprint of the user, the user is granted access if the fingerprint characteristics match the database and the correct login information is supplied.
A touch screen has a pressure-sensitive transparent panel. The computer receives instructions specific to the place on the screen that the user touches.
A scanner digitizes an image or document. The digitization of the image is stored as a file that can be displayed, printed, or altered. A bar code reader is a type of scanner that reads universal product code (UPC) bar codes. It is widely used for pricing and inventory information.
An output device is used to present information to the user from a computer. Here are some examples of output devices:
Monitors and projectors
Printers, scanners, and fax machines
Speakers and headphones
Monitors and Projectors
Monitors and projectors are primary output devices for a computer. There are different types of monitors, as shown in Figure 1. The most important difference between these monitor types is the technology used to create an image:
CRT – The cathode-ray tube (CRT) has three electron beams. Each beam directs colored phosphor on the screen that glows either red, blue, or green. Areas not struck by an electron beam do not glow. The combination of glowing and non-glowing areas creates the image on the screen. This technology is also used by most televisions. CRTs usually have a degauss button on the front that the user can press to remove discoloration caused by magnetic interference.
LCD – Liquid crystal display is commonly used in flat panel monitors, laptops, and some projectors. It consists of two polarizing filters with a liquid crystal solution between them. An electronic current aligns the crystals so that light can either pass through or not pass through. The effect of light passing through in certain areas and not in others is what creates the image. LCD comes in two forms, active matrix and passive matrix. Active matrix is sometimes called thin film transistor (TFT). TFT allows each pixel to be controlled, which creates very sharp color images. Passive matrix is less expensive than active matrix but does not provide the same level of image control. Passive matrix is not commonly used in laptops.
DLP – Digital light processing is another technology used in projectors. DLP projectors use a spinning color wheel with a microprocessor-controlled array of mirrors called a digital micromirror device (DMD). Each mirror corresponds to a specific pixel. Each mirror reflects light toward or away from the projector optics. This creates a monochromatic image of up to 1024 shades of gray in between white and black. The color wheel then adds the color data to complete the projected color image.
Monitor resolution refers to the level of image detail that can be reproduced. Figure 2 is a chart of common monitor resolutions. Higher resolution settings produce better image quality. Several factors are involved in monitor resolution:
Pixel – The term pixel is an abbreviation for picture element. Pixels are the tiny dots that comprise a screen. Each pixel consists of red, green, and blue.
Dot pitch – Dot pitch is the distance between pixels on the screen. A lower dot pitch number produces a better image.
Contrast ratio – The contrast ratio is a measurement of the difference in intensity of light between the brightest point (white) and the darkest point (black). A 10,000:1 contrast ratio shows dimmer whites and lighter blacks than a monitor with a contrast ratio of 1,000,000:1.
Refresh rate – The refresh rate is how often per second the image is rebuilt. A higher refresh rate produces a better image and reduces the level of flicker.
Interlace/Non-Interlace – Interlaced monitors create the image by scanning the screen two times. The first scan covers the odd lines, top to bottom, and the second scan covers the even lines. Non-interlaced monitors create the image by scanning the screen, one line at a time from top to bottom. Most CRT monitors today are non-interlaced.
Horizontal Vertical Colors (HVC) – The number of pixels in a line is the horizontal resolution. The number of lines in a screen is the vertical resolution. The number of colors that can be reproduced is the color resolution.
Aspect ratio – Aspect ratio is the horizontal to vertical measurement of the viewing area of a monitor. For example, a 4:3 aspect ratio would apply to a viewing area that is 16 inches wide by 12 inches high. A 4:3 aspect radio would also apply to a viewing area that is 24 inches wide by 18 inches high. A viewing area that is 22 inches wide by 12 inches high has an aspect ratio of 11:6.
Native resolution – Native resolution is the number of pixels that a monitor has. A monitor with a resolution of 1280x1024 has 1280 horizontal pixels and 1024 vertical pixels. Native mode is when the image sent to the monitor matches the native resolution of the monitor.
Monitors have controls for adjusting the quality of the image. Here are some common monitor settings:
Brightness – Intensity of the image
Contrast – Ratio of light to dark
Position – Vertical and horizontal location of image on the screen
Reset – Returns the monitor settings to factory settings
Adding additional monitors increases the number of windows that are visible on the desktop. Many computers have built-in support for multiple monitors. See Figure 3 for more information about configuring multiple monitors.
All-in-One Printer
Printers are output devices that create hard copies of computer files. Some printers specialize in particular applications, such as printing color photographs. Other all-in-one type printers, like the one shown in Figure 4, are designed to provide multiple services such as printing, scanning, faxing, and copying.
Speakers and Headphones
Speakers and headphones are output devices for audio signals. Most computers have audio support either integrated into the motherboard or on an adapter card. Audio support includes ports that allow input and output of audio signals. The audio card has an amplifier to power headphones and external speakers, which are shown in Figure 5.
System resources are used for communication purposes between the CPU and other components in a computer. There are three common system resources:
Interrupt Requests (IRQ)
Input/Output (I/O) Port Addresses
Direct Memory Access (DMA)
Interrupt Requests
IRQs are used by computer components to request information from the CPU. The IRQ travels along a wire on the motherboard to the CPU. When the CPU receives an interrupt request, the CPU determines how to fulfill this request. The priority of the request is determined by the IRQ number assigned to that computer component. Older computers only had eight IRQs to assign to devices. Newer computers have 16 IRQs, which are numbered 0 to 15, as shown in Figure 1. As a general rule, each component in the computer must be assigned a unique IRQ. IRQ conflicts can cause components to stop functioning and even cause the computer to crash. Today, most IRQ numbers are assigned automatically with plug and play (PnP) operating systems and the implementation of PCI slots, USB ports, and FireWire ports. With the numerous components that can be installed in a computer, it is difficult to assign a unique IRQ to every component. PCI devices can now share IRQs without conflict.
Input/Output (I/O) Port Addresses
Input/output (I/O) port addresses are used to communicate between devices and software. The I/O port address is used to send and receive data for a component. As with IRQs, each component will have a unique I/O port assigned. There are 65,535 I/O ports in a computer, and they are referenced by a hexadecimal address in the range of 0000h to FFFFh. Figure 2 shows a chart of common I/O ports.
Direct Memory Access
DMA channels are used by high-speed devices to communicate directly with main memory. These channels allow the device to bypass interaction with the CPU and directly store and retrieve information from memory. Only certain devices can be assigned a DMA channel, such as SCSI host adapters and sound cards. Older computers only had four DMA channels to assign to components. Newer computers have eight DMA channels that are numbered 0 to 7, as shown in Figure 3.
This chapter introduced the IT industry, options for training and employment, and some of the industry-standard certifications. This chapter also covered the components that comprise a personal computer system. Much of the content in this chapter will help you throughout this course:
Information Technology encompasses the use of computers, network hardware, and software to process, store, transmit, and retrieve information.
A personal computer system consists of hardware components and software applications.
The computer case and power supply must be chosen carefully to support the hardware inside the case and allow for the addition of components.
The internal components of a computer are selected for specific features and functions. All internal components must be compatible with the motherboard.
You should use the correct type of ports and cables when connecting devices.
Typical input devices include the keyboard, mouse, touch screen, and digital cameras.
Typical output devices include monitors, printers, and speakers.
System resources must be assigned to computer components. System resources include IRQs, I/O port addresses, and DMAs
CHapter 2
This chapter covers basic safety practices for the workplace, hardware and software tools, and the disposal of hazardous materials. Safety guidelines help protect individuals from accidents and injury and protect equipment from damage. Some of these guidelines are designed to protect the environment from contamination by discarded materials. Stay alert to situations that could result in injury or damage to equipment. Warning signs are designed to alert you to danger. Always watch for these signs and take the appropriate action according to the warning given.
After completing this chapter, you will meet these objectives:
Explain the purpose of safe working conditions and procedures.
Identify tools and software used with personal computer components and their purposes.
Implement proper tool use.
Safe working conditions help to prevent injury to people and damage to computer equipment. A safe workspace is clean, organized, and properly lighted. Everyone must understand and follow safety procedures.
Follow proper procedures for handling computer equipment to reduce the risk of personal injury, damage to property, and loss of data. Any damage or loss may result in claims for damage from the owner of the property and data.
The proper disposal or recycling of hazardous computer components is a global issue. Make sure to follow regulations that govern how to dispose of specific items. Organizations that violate these regulations can be fined or face expensive legal battles.
After completing this section, you will meet these objectives:
Identify safety procedures and potential hazards for users and technicians.
Identify safety procedures to protect equipment from damage and data from loss.
Identify safety procedures to protect the environment from contamination.
General Safety Guidelines
Follow the basic safety guidelines to prevent cuts, burns, electrical shock, and damage to eyesight. As is best practice, make sure that a fire extinguisher and first-aid kit are available in case of fire or injury. Poorly placed or unsecured cables usually cause tripping hazards in a network installation. Cables should be installed in conduit or cable trays to prevent hazards to users. Figure 1 shows a list of general safety guidelines.
Electrical Safety Guidelines
Follow electrical safety guidelines to prevent electrical fires, injuries, and fatalities in the home and the workplace. Power supplies and monitors contain very high voltage. Only experienced technicians should attempt to repair power supplies and monitors, while most users should simply replace them. Do not wear the antistatic wrist strap when repairing power supplies or monitors.
Some printer parts may become very hot when in use, and other parts may contain very high voltages. Make sure that the printer has had time to cool before making the repair. Check the printer manual for locations of various components that may contain high voltages. Some components may retain high voltages even after the printer is turned off.
Electrical devices have certain power requirements. For example, AC adapters are manufactured for specific laptops. Exchanging power cords with a different type of laptop or device may cause damage to both the AC adapter and the laptop.
Fire Safety Guidelines
Follow fire safety guidelines to protect lives, structures, and equipment. To avoid an electrical shock, and to prevent damage to the computer, turn off and unplug the computer before beginning a repair.
Fire can spread rapidly and be very costly. Proper use of a fire extinguisher can prevent a small fire from getting out of control. When working with computer components, always consider the possibility of an accidental fire and know how to react. You should be alert for odors emitting from computers and electronic devices. When electronic components overheat or short out, they will emit a burning odor. If there is a fire, you should follow these safety procedures:
Never fight a fire that is out of control or not contained.
Always have a planned fire escape route before beginning any work.
Get out of the building quickly.
Contact emergency services for help.
Be sure to locate and read the instructions on the fire extinguishers in your workplace before you have to use them. Safety training may be available in your organization.
In the United States, there are four classifications for fire extinguishers. A different letter, color, and shape identify each fire extinguisher classification, as shown in Figure 2. Each type of fire extinguisher has specific chemicals to fight different types of fires:
Wtocsua9pcasdrieo800m – IEEE 1394b
Anaitastkcwmtttstanrltnpttswitnottoa – pod
Wcttcoooapiintctcotcwtcaawaip – ic,p
Class A – Paper, wood, plastics, cardboard
Class B – Gasoline, kerosene, organic solvents
Class C – Electrical equipment
Class D – Combustible metals
What types of fire extinguisher classifications are there in your country?
It is important to know how to use a fire extinguisher. Use the memory aid P-A-S-S to help you remember the basic rules of fire extinguisher operation:
P - Pull the pin.
A - Aim at the base of the fire, not at the flames.
S - Squeeze the lever.
S - Sweep the nozzle from side to side.
Electrostatic discharge (ESD), harsh climates, and poor-quality sources of electricity can cause damage to computer equipment. Follow proper handling guidelines, be aware of environmental issues, and use equipment that stabilizes power to prevent equipment damage and data loss.
ESD
Static electricity is the buildup of an electric charge resting on a surface. This buildup may jump to a component and cause damage. This is known as electrostatic discharge (ESD). ESD can be destructive to the electronics in a computer system.
At least 3,000 volts of static electricity must build up before a person can feel ESD. For example, static electricity can build up on you as you walk across a carpeted floor. When you touch another person, you both receive a shock. If the discharge causes pain or makes a noise, the charge was probably above 10,000 volts. By comparison, less than 30 volts of static electricity can damage a computer component.
ESD Protection Recommendations
ESD can cause permanent damage to electrical components. Follow these recommendations to help prevent ESD damage:
Keep all components in antistatic bags until you are ready to install them.
Use grounded mats on workbenches.
Use grounded floor mats in work areas.
Use antistatic wrist straps when working on computers.
EMI
Electromagnetic Interference (EMI) is the intrusion of outside electromagnetic signals in a transmission media, such as copper cabling. In a network environment, EMI distorts the signals so that the receiving devices have difficulty interpreting them.
EMI does not always come from expected sources such as cellular phones. Other types of electric equipment can emit a silent, invisible electromagnetic field that can extend for more than a mile.
As shown in Figure 1, there are many sources of EMI:
Any source designed to generate electromagnetic energy
Man-made sources like power lines or motors
Natural events such as electrical storms or solar and interstellar radiations
Wireless networks are affected by Radio Frequency Interference (RFI). RFI is the interference caused by radio transmitters and other devices transmitting in the same frequency. For example, a cordless telephone can cause problems with a wireless network when both devices use the same frequency. Microwaves can also cause interference when positioned in close proximity to wireless networking devices.
Climate
Climate affects computer equipment in a variety of ways:
If the environment temperature is too high, equipment can overheat.
If the humidity level is too low, the chance of ESD increases.
If the humidity level is too high, equipment can suffer from moisture damage.
Figure 2 shows how environmental conditions increase or decrease the risk of ESD.
Power Fluctuation Types
Voltage is the force that moves electrons through a circuit. The movement of electrons is called current. Computer circuits need voltage and current to operate electronic components. When the voltage in a computer is not accurate or steady, computer components may not operate correctly. Unsteady voltages are called power fluctuations.
The following types of AC power fluctuations can cause data loss or hardware failure:
Blackout – Complete loss of AC power. A blown fuse, damaged transformer, or downed power line can cause a blackout.
Brownout – Reduced voltage level of AC power that lasts for a period of time. Brownouts occur when the power line voltage drops below 80% of the normal voltage level. Overloading electrical circuits can cause a brownout.
Noise – Interference from generators and lightning. Noise results in unclean power, which can cause errors in a computer system.
Spike – Sudden increase in voltage that lasts for a very short period and exceeds 100% of the normal voltage on a line. Spikes can be caused by lightning strikes, but can also occur when the electrical system comes back on after a blackout.
Power surge – Dramatic increase in voltage above the normal flow of electrical current. A power surge lasts for a few nanoseconds, or one-billionth of a second.
Power Protection Devices
To help shield against power fluctuation issues, use protection devices to protect the data and computer equipment:
Surge suppressor – Helps protect against damage from surges and spikes. A surge suppressor diverts extra electrical voltage on the line to the ground.
Uninterruptible Power Supply (UPS) – Helps protect against potential electrical power problems by supplying electrical power to a computer or other device. The battery is constantly recharging while the UPS is in use. The UPS is able to supply a consistent quality of power when brownouts and blackouts occur. Many UPS devices are able to communicate directly with the operating system on a computer. This communication allows the UPS to safely shut down the computer and save data prior to the UPS losing all electrical power.
Standby Power Supply (SPS) – Helps protect against potential electrical power problems by providing a backup battery to supply power when the incoming voltage drops below the normal level. The battery is on standby during the normal operation. When the voltage decreases, the battery provides DC power to a power inverter, which converts it to AC power for the computer. This device is not as reliable as a UPS because of the time it takes to switch over to the battery. If the switching device fails, the battery will not be able to supply power to the computer. Figure 3 shows some examples of surge suppressors, UPS, and SPS devices.
CAUTION: Never plug a printer into a UPS device. UPS manufacturers suggest never plugging a printer into a UPS for fear of overloading the UPS.
Computers and peripherals, as shown in Figure 1, contain materials that can be harmful to the environment. Hazardous materials are sometimes called toxic waste. These materials can contain high concentrations of heavy metals such as cadmium, lead, or mercury. The regulations for the disposal of hazardous materials vary according to state or country. Contact the local recycling or waste removal authorities in your community for information about disposal procedures and services.
Material Safety and Data Sheet
A Material Safety and Data Sheet (MSDS) is a fact sheet that summarizes information about material identification, including hazardous ingredients that can affect personal health, fire hazards, and first aid requirements. In Figure 2, the MSDS sheet contains chemical reactivity and incompatibility information that includes spill, leak, and disposal procedures. It also includes protective measures for the safe handling and storage of materials.
To determine if a material is classified as hazardous, consult the manufacturer's MSDS. In the U.S., the Occupational Safety and Health Administration (OSHA) requires that all hazardous materials must be accompanied by an MSDS when transferred to a new owner. The MSDS information included with products purchased for computer repairs or maintenance can be relevant to computer technicians. OSHA also requires that employees be informed about the materials that they are working with and be provided with material safety information. In the United Kingdom, Chemicals Hazard Information and Packaging for Supply Regulations 2002 (CHIP3) oversees the handling of hazardous materials. CHIP3 requires chemical suppliers to safely package and transport dangerous chemicals and to include a data sheet with the product.
NOTE: The MSDS is valuable in determining how to dispose of any potentially hazardous materials in the safest manner. Always check local regulations concerning acceptable disposal methods before disposing of any electronic equipment.
Which organization governs the use of hazardous chemicals in your country? Are MSDS sheets mandatory?
The MSDS contains valuable information:
The name of the material
The physical properties of the material
Any hazardous ingredients contained in the material
Reactivity data, such as fire and explosion data
Procedures for spills or leaks
Special precautions
Health hazards
Special protection requirements
Computers and other computing devices are eventually discarded because of one of the following reasons:
Parts or components begin to fail more frequently as the device ages.
The computer becomes obsolete for the application for which it was originally intended.
Newer models have improved features.
Before discarding a computer or any of its components, it is crucial to consider safe disposal of each separate component.
Proper Disposal of Batteries
Batteries often contain rare earth metals that can be harmful to the environment. Batteries from portable computer systems may contain lead, cadmium, lithium, alkaline manganese, and mercury. These metals do not decay and will remain in the environment for many years. Mercury is commonly used in the manufacturing of batteries and is extremely toxic and harmful to humans.
Recycling batteries should be a standard practice for a technician. All batteries, including lithium-ion, nickel-cadmium, nickel-metal hydride, and lead-acid are subject to disposal procedures that comply with local environmental regulations.
Proper Disposal of Monitors or CRTs
Handle monitors and CRTs with care. Extremely high voltage can be stored in monitors and CRTs, even after being disconnected from a power source. CRTs contain glass, metal, plastics, lead, barium, and rare earth metals. According to the U.S. Environmental Protection Agency (EPA), CRTs may contain approximately 4 lbs (1.8 kg) of lead. Monitors must be disposed of in compliance with environmental regulations.
Proper Disposal of Toner Kits, Cartridges, and Developers
Used printer toner kits and printer cartridges must be disposed of properly or recycled. Some toner cartridge suppliers and manufacturers will take empty cartridges for refilling. There are also companies that specialize in refilling empty cartridges. Kits to refill inkjet printer cartridges are available but are not recommended, because the ink may leak into the printer, causing irreversible damage. This can be especially costly because using refilled inkjet cartridges may also void the inkjet printer warranty.
Proper Disposal of Chemical Solvents and Aerosol Cans
Contact the local sanitation company to learn how and where to dispose of the chemicals and solvents used to clean computers. Never dump chemicals or solvents down a sink or dispose of them in any drain that connects to public sewers.
The cans or bottles that contain solvents and other cleaning supplies must be handled carefully. Make sure that they are identified and treated as special hazardous waste. For example, some aerosol cans may explode when exposed to heat if the contents are not completely used.
For every job there is the right tool. Make sure that you are familiar with the correct use of each tool and that the right tool is used for the current task. Skilled use of tools and software makes the job less difficult and ensures that tasks are performed properly and safely.
Software tools are available that help diagnose problems. Use these tools to determine which computer device is not functioning correctly.
A technician must document all repairs and computer problems. The documentation can then be used as a reference for future problems or for other technicians who may not have encountered the problem before. The documents may be paper-based, but electronic forms are preferred because they can be easily searched for specific problems.
After completing this section, you will meet these objectives:
Identify hardware tools and their purpose.
Identify software tools and their purpose.
Identify organizational tools and their purpose.
A toolkit should contain all of the tools necessary to complete hardware repairs. As you gain experience, you will learn which tools to have available for different types of jobs. Hardware tools are grouped into these four categories:
ESD tools
Hand tools
Cleaning tools
Diagnostic tools
ESD Tools
There are two ESD tools: the antistatic wrist strap and the antistatic mat. The antistatic wrist strap protects computer equipment when grounded to a computer chassis. The antistatic mat protects computer equipment by preventing static electricity from accumulating on the hardware or on the technician. Click each of the items in Figure 1 for more information on ESD tools.
Hand Tools
Most tools used in the computer assembly process are small hand tools. They are available individually or as part of a computer repair toolkit. Toolkits range widely in size, quality, and price. Click each of the items in Figure 2 for more information on hand tools.
Cleaning Tools
Having the appropriate cleaning tools is essential when maintaining or repairing computers. Using these tools ensures that computer components are not damaged during cleaning. Click each of the items in Figure 3 for more information on cleaning tools.
Diagnostic Tools
A digital multimeter and a loopback adapter are used to test hardware. Click each of the items in Figure 4 for more information on diagnostic tools.
A technician must be able to use a range of software tools to help diagnose problems, maintain hardware, and protect the data stored on a computer.
Disk Management Tools
You must be able to identify which software to use in different situations. Disk management tools help detect and correct disk errors, prepare a disk for data storage, and remove unwanted files.
Click each of the buttons in Figure 1 to see screen shots of the following disk management tools:
Fdisk or Disk Management – Creates and deletes partitions on a hard drive
Format – Prepares a hard drive to store information
Scandisk or Chkdsk – Checks the integrity of files and folders on a hard drive by scanning the file system. These tools may also check the disk surface for physical errors
Defrag – Optimizes space on a hard drive to allow faster access to programs and data
Disk Cleanup – Clears space on a hard drive by searching for files that can be safely deleted
Disk Management – Initializes disks, creates partitions, and formats partitions
System File Checker (SFC) – Scans the operating system critical files and replaces any files that are corrupted
Use the Windows XP boot disk for troubleshooting and repairing corrupted files. The Windows XP boot disk is designed to repair Windows system files, restore damaged or lost files, and reinstall the operating system. Third-party software tools are available to assist in troubleshooting problems.
Protection Software Tools
Each year, viruses, spyware, and other types of malicious attacks infect millions of computers. These attacks can damage an operating system, application, and data. Computers that have been infected may even have problems with hardware performance or component failure.
To protect data and the integrity of the operating system and hardware, use software designed to guard against attacks and to remove malicious programs.
Various types of software are used to protect hardware and data. Click each of the buttons in Figure 2 to see screen shots of these protection software tools:
Windows XP Security Center – Checks the status of essential security settings. The Security Center continuously checks to make sure that the software firewall and antivirus programs are running. It also ensures that automatic updates are set to download and install automatically.
Antivirus program – Protects against virus attacks.
Spyware remover – Protects against software that sends information about web surfing habits to an attacker. Spyware can be installed without the knowledge or consent of the user.
Firewall program – Runs continuously to protect against unauthorized communications to and from your computer.
It is important that a technician document all services and repairs. These documents need to be stored centrally and made available to all other technicians. The documentation can then be used as reference material for similar problems that are encountered in the future. Good customer service includes providing the customer with a detailed description of the problem and the solution.
Personal Reference Tools
Personal reference tools include troubleshooting guides, manufacturer manuals, quick reference guides, and repair journals. In addition to an invoice, a technician keeps a journal of upgrades and repairs. The documentation in the journal should include descriptions of the problem, possible solutions that have been attempted, and the steps taken to repair the problem. Be sure to note any configuration changes made to the equipment and any replacement parts used in the repair. This documentation will be valuable when you encounter similar situations in the future.
Notes – Make notes as you go through the investigation and repair process. Refer to these notes to avoid repeating previous steps and to determine what steps to take next.
Journal – Document the upgrades and repairs that you perform. The documentation should include descriptions of the problem, possible solutions that have been tried in order to correct the problem, and the steps taken to repair the problem. Be sure to note any configuration changes made to the equipment and any replacement parts used in the repair. Your journal, along with your notes, can be valuable when you encounter similar situations in the future.
History of repairs – Make a detailed list of problems and repairs, including the date, replacement parts, and customer information. The history allows a technician to determine what work has been performed on a computer in the past.
Internet Reference Tools
The Internet is an excellent source of information about specific hardware problems and possible solutions:
Internet search engines
News groups
Manufacturer FAQs
Online computer manuals
Online forums and chat
Technical websites
Figure 1 shows an example of a technical website.
Miscellaneous Tools
With experience, you will discover many additional items to add to the toolkit. Figure 2 shows how a roll of masking tape can be used to label parts that have been removed from a computer when a parts organizer is not available.
A working computer is also a valuable resource to take with you on computer repairs in the field. A working computer can be used to research information, download tools or drivers, or communicate with other technicians.
Figure 3 shows the types of computer replacement parts to include in a toolkit. Make sure that the parts are in good working order before you use them. Using known good components to replace possible bad ones in computers will help you quickly determine which component may not be working properly.
Safety in the workplace is everyone's responsibility. You are much less likely to injure yourself or damage components when using the proper tool for the job.
Before cleaning or repairing equipment, check to make sure that your tools are in good condition. Clean, repair, or replace any items that are not functioning adequately.
After completing this section, you will meet these objectives:
Demonstrate proper use of an antistatic wrist strap.
Demonstrate proper use of an antistatic mat.
Demonstrate proper use of various hand tools.
Demonstrate proper use of cleaning materials.
As discussed previously, an example of ESD is the small shock that you receive when you walk across a room with carpet and touch a doorknob. Although the small shock is harmless to you, the same electrical charge passing from you to a computer can damage its components. Wearing an antistatic wrist strap can prevent ESD damage to computer components.
The purpose of an antistatic wrist strap is to equalize the electrical charge between you and the equipment. The antistatic wrist strap is a conductor that connects your body to the equipment that you are working on. When static electricity builds up in your body, the connection made by the wrist strap to the equipment, or ground, channels the electricity through the wire that connects the strap.
As shown in Figure 1, the wrist strap has two parts and is easy to wear:
Wrap the strap around your wrist and secure it using the snap or Velcro. The metal on the back of the wrist strap must remain in contact with your skin at all times.
Snap the connector on the end of the wire to the wrist strap, and connect the other end either to the equipment or to the same grounding point that the antistatic mat is connected to. The metal skeleton of the case is a good place to connect the wire. When connecting the wire to equipment that you are working on, choose an unpainted metal surface. A painted surface does not conduct the electricity as well as unpainted metal.
NOTE: Attach the wire on the same side of the equipment as the arm wearing the antistatic wrist strap. This will help to keep the wire out of the way while you are working.
Although wearing a wrist strap will help to prevent ESD, you can further reduce the risks by not wearing clothing made of silk, polyester, or wool. These fabrics are more likely to generate a static charge.
NOTE: Technicians should roll up their sleeves, remove scarfs or ties, and tuck in their shirts to prevent interference from clothing. Ensure that earrings, necklaces, and other loose jewelry are properly secured.
CAUTION: Never wear an antistatic wrist strap if you are repairing a monitor or a power supply unit.
You may not always have the option to work on a computer in a properly equipped workspace. If you can control the environment, try to set up your workspace away from carpeted areas. Carpets can cause the buildup of electrostatic charges. If you cannot avoid the carpeting, ground yourself to the unpainted portion of the case of the computer on which you are working before touching any components.
Antistatic Mat
An antistatic mat is slightly conductive. It works by drawing static electricity away from a component and transferring it safely from equipment to a grounding point, as shown in Figure 1:
Lay the mat on the workspace next to or under the computer case.
Clip the mat to the case to provide a grounded surface on which you can place parts as you remove them from the system.
Reducing the potential for ESD reduces the likelihood of damage to delicate circuits or components.
NOTE: Always handle components by the edges.
Workbench
When you are working at a workbench, ground the workbench and the antistatic floor mat. By standing on the mat and wearing the wrist strap, your body has the same charge as the equipment and reduces the probability of ESD.
A technician needs to be able to properly use each tool in the toolkit. This topic covers many of the various hand tools used when repairing computers.
Screws
Match each screw with the proper screwdriver. Place the tip of the screwdriver on the head of the screw. Turn the screwdriver clockwise to tighten the screw and counterclockwise to loosen the screw, as shown in Figure 1.
Screws can become stripped if you over-tighten them with a screwdriver. A stripped screw, shown in Figure 2, may get stuck in the screw hole, or it may not tighten firmly. Discard stripped screws.
Flat Head Screwdriver
As shown in Figure 3, use a flat head screwdriver when you are working with a slotted screw. Do not use a flat head screwdriver to remove a Phillips head screw. Never use a screwdriver as a pry bar. If you cannot remove a component, check to see if there is a clip or latch that is securing the component in place.
CAUTION: If excessive force is needed to remove or add a component, something is probably wrong. Take a second look to make sure that you have not missed a screw or a locking clip that is holding the component in place. Refer to the device manual or diagram for additional information.
Phillips Head Screwdriver
As shown in Figure 4, use a Phillips head screwdriver with crosshead screws. Do not use this type of screwdriver to puncture anything. This will damage the head of the screwdriver.
Hex Driver
As shown in Figure 5, use a hex driver to loosen and tighten bolts that have a hexagonal (six-sided) head. Hex bolts should not be over-tightened because the threads of the bolts can be stripped. Do not use a hex driver that is too large for the bolt that you are using.
CAUTION: Some tools are magnetized. When working around electronic devices, be sure that the tools you are using have not been magnetized. Magnetic fields can be harmful to data stored on magnetic media. Test your tool by touching the tool with a screw. If the screw is attracted to the tool, do not use the tool.
Part Retriever, Needle-Nose Pliers, or Tweezers
As shown in Figure 6, the part retriever, needle-nose pliers, and tweezers can be used to place and retrieve parts that may be hard to reach with your fingers. Do not scratch or hit any components when using these tools.
CAUTION: Pencils should not be used inside the computer to change the setting of switches or to pry off jumpers. The pencil lead can act as a conductor and may damage the computer components.
Keeping computers clean inside and out is a vital part of a maintenance program. Dirt can cause problems with the physical operation of fans, buttons, and other mechanical components. Figure 1 shows severe dust buildup on computer components. On electrical components, an excessive buildup of dust will act like an insulator and trap the heat. This insulation will impair the ability of heat sinks and cooling fans to keep components cool, causing chips and circuits to overheat and fail.
CAUTION: When compressed air is used to clean inside the computer, the air should be blown around the components with a minimum distance of four inches from the nozzle. The power supply and the fan should be cleaned from the back of the case.
CAUTION: Before cleaning any device, turn it off and unplug the device from the power source.
Computer Cases and Monitors
Clean computer cases and the outside of monitors with a mild cleaning solution on a damp, lint-free cloth. Mix one drop of dishwashing liquid with four ounces of water to create the cleaning solution. If any water drips inside the case, allow enough time for the liquid to dry before powering on the computer.
LCD Screens
Do not use ammoniated glass cleaners or any other solution on an LCD screen, unless the cleaner is specifically designed for the purpose. Harsh chemicals will damage the coating on the screen. There is no glass protecting these screens, so be gentle when cleaning them and do not press firmly on the screen.
CRT Screens
To clean the screens of CRT monitors, dampen a soft, clean, lint-free cloth with distilled water and wipe the screen from top to bottom. Then use a soft, dry cloth to wipe the screen and remove any streaking after you have cleaned the monitor.
Clean dusty components with a can of compressed air. Compressed air does not cause electrostatic buildup on components. Make sure that you are in a well-ventilated area before blowing the dust out of the computer. A best practice is to wear a dust mask to make sure that you do not breathe in the dust particles.
Blow out the dust using short bursts from the can. Never tip the can or use the compressed air can upside down. Do not allow the fan blades to spin from the force of the compressed air. Hold the fan in place. Fan motors can be ruined from spinning when the motor is not turned on.
Component Contacts
Clean the contacts on components with isopropyl alcohol. Do not use rubbing alcohol. Rubbing alcohol contains impurities that can damage contacts. Make sure that the contacts do not collect any lint from the cloth or cotton swab. Blow any lint off the contacts with compressed air before reinstallation.
Keyboard
Clean a desktop keyboard with compressed air or a small, hand-held vacuum cleaner with a brush attachment.
CAUTION: Never use a standard vacuum cleaner inside a computer case. The plastic parts of the vacuum cleaner can build up static electricity and discharge to the components. Use only a vacuum approved for electronic components.
Mouse
Use glass cleaner and a soft cloth to clean the outside of the mouse. Do not spray glass cleaner directly on the mouse. If cleaning a ball mouse, you can remove the ball and clean it with glass cleaner and a soft cloth. Wipe the rollers clean inside the mouse with the same cloth. Do not spray any liquids inside the mouse.
The chart in Figure 2 indicates the computer items that you should clean and the cleaning materials that you should use in each case.
This chapter discussed safe lab procedures, correct tool usage, and the proper disposal of computer components and supplies. You have familiarized yourself in the lab with many of the tools used to build, service, and clean computer and electronic components. You have also learned the importance of organizational tools and how these tools help you work more efficiently.
The following are some of the important concepts to remember from this chapter:
Work in a safe manner to protect both users and equipment.
Follow all safety guidelines to prevent injuries to yourself and to others.
Know how to protect equipment from ESD damage.
Know about and be able to prevent power issues that can cause equipment damage or data loss.
Know which products and supplies require special disposal procedures.
Familiarize yourself with MSDS sheets for both safety issues and disposal restrictions to help protect the environment.
Be able to use the correct tools for the task.
Know how to clean components safely.
Use organizational tools during computer repairs.
Chapter 3
Computer cases are produced in a variety of form factors. Form factors refer to the size and shape of the case.
Prepare the workspace before opening the computer case. There should be adequate lighting, good ventilation, and a comfortable room temperature. The workbench or table should be accessible from all sides. Avoid cluttering the surface of the workbench or table with tools and computer components. An antistatic mat on the table will help prevent physical and ESD damage to equipment. Small containers can be used to hold small screws and other parts as they are being removed.
There are different methods for opening cases. To learn how to open a particular computer case, consult the user manual or manufacturer's website. Most computer cases are opened in one of the following ways:
The computer case cover can be removed as one piece.
The top and side panels of the case can be removed.
The top of the case may need to be removed before the side panels can be removed.
A technician may be required to replace or install a power supply. Most power supplies can only fit one way in the computer case. There are usually three or four screws that attach the power supply to the case. Power supplies have fans that can vibrate and loosen screws that are not secured. When installing a power supply, make sure that all of the screws are used and that they are properly tightened.
These are the power supply installation steps:
Insert the power supply into the case.
Align the holes in the power supply with the holes in the case.
Secure the power supply to the case using the proper screws.
This section details the steps to install components on the motherboard and then install the motherboard into the computer case.
After completing this section, you will meet these objectives:
Install a CPU and a heat sink/fan assembly.
Install the RAM.
Install the motherboard.
The CPU and the heat sink/fan assembly may be installed on the motherboard before the motherboard is placed in the computer case.
CPU
Figure 1 shows a close-up view of the CPU and the motherboard. The CPU and motherboard are sensitive to electrostatic discharge. When handling a CPU and motherboard, make sure that you place them on a grounded antistatic mat. You should wear an antistatic wrist strap while working with these components.
CAUTION: When handling a CPU, do not touch the CPU contacts at any time.
The CPU is secured to the socket on the motherboard with a locking assembly. The CPU sockets today are ZIF sockets. You should be familiar with the locking assembly before attempting to install a CPU into the socket on the motherboard.
Thermal compound helps to conduct heat away from the CPU. Figure 2 shows thermal compound being applied to the CPU.
When you are installing a used CPU, clean the CPU and the base of the heat sink with isopropyl alcohol. Doing this removes all traces of old thermal compound. The surfaces are now ready for a new layer of thermal compound. Follow all manufacturer recommendations about applying the thermal compound.
Heat Sink/Fan Assembly
Figure 3 shows the heat sink/fan assembly. It is a two-part cooling device. The heat sink draws heat away from the CPU. The fan moves the heat away from the heat sink. The heat sink/fan assembly usually has a 3-pin power connector.
Figure 4 shows the connector and the motherboard header for the heat sink/fan assembly.
Follow these instructions for CPU and heat sink/fan assembly installation:
Align the CPU so that the Connection 1 indicator is lined up with Pin 1 on the CPU socket. Doing this ensures that the orientation notches on the CPU are aligned with the orientation keys on the CPU socket.
Place the CPU gently into the socket.
Close the CPU load plate and secure it in place by closing the load lever and moving it under the load lever retention tab.
Apply a small amount of thermal compound to the CPU and spread it evenly. Follow the application instructions provided by the manufacturer.
Align the heat sink/fan assembly retainers with the holes on the motherboard.
Place the heat sink/fan assembly onto the CPU socket, being careful not to pinch the CPU fan wires.
Tighten the heat sink/fan assembly retainers to secure the assembly in place.
Connect the heat sink/fan assembly power cable to the header on the motherboard.
Like the CPU and the heat sink/fan assembly, RAM is installed in the motherboard before the motherboard is secured in the computer case. Before you install a memory module, consult the motherboard documentation or website of the manufacturer to ensure that the RAM is compatible with the motherboard.
RAM provides temporary data storage for the CPU while the computer is operating. RAM is volatile memory, which means that its contents are lost when the computer is shut down. Typically, more RAM will enhance the performance of your computer.
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Follow these steps for RAM installation:
Align the notches on the RAM module to the keys in the slot and press down until the side tabs click into place.
Make sure that the side tabs have locked the RAM module. Visually check for exposed contacts.
Repeat these steps for additional RAM modules.
The motherboard is now ready to install in the computer case. Plastic and metal standoffs are used to mount the motherboard and to prevent it from touching the metal portions of the case. You should install only the standoffs that align with the holes in the motherboard. Installing any additional standoffs may prevent the motherboard from being seated properly in the computer case.
Follow these steps for motherboard installation:
Install standoffs in the computer case.
Align the I/O connectors on the back of the motherboard with the openings in the back of the case.
Align the screw holes of the motherboard with the standoffs.
Insert all of the motherboard screws.
Tighten all of the motherboard screws.
Drives that are installed in internal bays are called internal drives. A hard disk drive (HDD) is an example of an internal drive.
Follow these steps for HDD installation:
Position the HDD so that it aligns with the 3.5-inch drive bay.
Insert the HDD into the drive bay so that the screw holes in the drive line up with the screw holes in the case.
Secure the HDD to the case using the proper screws.
Drives, such as optical drives and floppy drives, are installed in drive bays that are accessed from the front of the case. Optical drives and floppy drives store data on removable media. Drives in external bays allow access to the media without opening the case.
After completing this section, you will meet these objectives:
Install the optical drive.
Install the floppy drive.
An optical drive is a storage device that reads and writes information to CDs and DVDs. A Molex power connector provides the optical drive with power from the power supply. A PATA cable connects the optical drive to the motherboard.
Follow these steps for optical drive installation:
Position the optical drive so that it aligns with the 5.25-inch drive bay.
Insert the optical drive into the drive bay so that the optical drive screw holes align with the screw holes in the case.
Secure the optical drive to the case using the proper screws.
A floppy disk drive (FDD) is a storage device that reads and writes information to a floppy disk. A Berg power connector provides the FDD with power from the power supply. A floppy data cable connects the FDD to the motherboard.
A floppy disk drive fits into the 3.5-inch bay on the front of the computer case.
Follow these steps for FDD installation:
Position the FDD so that it aligns with the 3.5-inch drive bay.
Insert the FDD into the drive bay so that the FDD screw holes align with the screw holes in the case.
Secure the FDD to the case using the proper screws.
Adapter cards are installed to add functionality to a computer. Adapter cards must be compatible with the expansion slot. This section focuses on the installation of three types of adapter cards:
PCIe x1 NIC
PCI wireless NIC
PCIe x16 video adapter card
After completing this section, you will meet these objectives:
Install the NIC.
Install the wireless NIC.
Install the video adapter card.
A NIC enables a computer to connect to a network. NICs use PCI and PCIe expansion slots on the motherboard.
Follow these steps for NIC installation:
Align the NIC to the appropriate expansion slot on the motherboard.
Press down gently on the NIC until the card is fully seated.
Secure the NIC PC mounting bracket to the case with the appropriate screw.
A wireless NIC enables a computer to connect to a wireless network. Wireless NICs use PCI and PCIe expansion slots on the motherboard. Some wireless NICs are installed externally with a USB connector.
Follow these steps for wireless NIC installation:
Align the wireless NIC to the appropriate expansion slot on the motherboard.
Press down gently on the wireless NIC until the card is fully seated.
Secure the wireless NIC PC mounting bracket to the case with the appropriate screw.
A video adapter card is the interface between a computer and a display monitor. An upgraded video adapter card can provide better graphic capabilities for games and graphic programs. Video adapter cards use PCI, AGP, and PCIe expansion slots on the motherboard.
Follow these steps for video adapter card installation:
Align the video adapter card to the appropriate expansion slot on the motherboard.
Press down gently on the video adapter card until the card is fully seated.
Secure the video adapter card PC mounting bracket to the case with the appropriate screw.
Power cables are used to distribute electricity from the power supply to the motherboard and other components. Data cables transmit data between the motherboard and storage devices, such as hard drives. Additional cables connect the buttons and link lights on the front of the computer case to the motherboard.
After completing this section, you will meet these objectives:
Connect the power cables.
Connect the data cables.
Motherboard Power Connections
Just like other components, motherboards require power to operate. The Advanced Technology Extended (ATX) main power connector will have either 20 or 24 pins. The power supply may also have a 4-pin or 6-pin Auxiliary (AUX) power connector that connects to the motherboard. A 20-pin connector will work in a motherboard with a 24-pin socket.
Follow these steps for motherboard power cable installation:
Align the 20-pin ATX power connector to the socket on the motherboard. [Figure 1]
Gently press down on the connector until the clip clicks into place.
Align the 4-pin AUX power connector to the socket on the motherboard. [Figure 2]
Gently press down on the connector until the clip clicks into place.
SATA Power Connectors
SATA power connectors use a 15-pin connector. SATA power connectors are used to connect to hard disk drives, optical drives, or any devices that have a SATA power socket.
Molex Power Connectors
Hard disk drives and optical drives that do not have SATA power sockets use a Molex power connector.
CAUTION: Do not use a Molex connector and a SATA power connector on the same drive at the same time.
Berg Power Connectors
The 4-pin Berg power connector supplies power to a floppy drive.
Follow these steps for power connector installation:
Plug the SATA power connector into the HDD. [Figure 3]
Plug the Molex power connector into the optical drive. [Figure 4]
Plug the 4-pin Berg power connector into the FDD. [Figure 5]
Connect the 3-pin fan power connector into the appropriate fan header on the motherboard, according to the motherboard manual. [Figure 6]
Plug the additional cables from the case into the appropriate connectors according to the motherboard manual.
Drives connect to the motherboard using data cables. The drive being connected determines the type of data cable used. The types of data cables are PATA, SATA, and floppy disk.
PATA Data Cables
The PATA cable is sometimes called a ribbon cable because it is wide and flat. The PATA cable can have either 40 or 80 conductors. A PATA cable usually has three 40-pin connectors. One connector at the end of the cable connects to the motherboard. The other two connectors connect to drives. If multiple hard drives are installed, the master drive connects to the end connector. The slave drive connects to the middle connector.
A stripe on the data cable denotes the location of pin 1. Plug the PATA cable into the drive with the pin 1 indicator on the cable aligned to the pin 1 indicator on the drive connector. The pin 1 indicator on the drive connector is usually closest to the power connector on the drive. Many motherboards have two PATA drive controllers, providing support for a maximum of four PATA drives.
SATA Data Cables
The SATA data cable has a 7-pin connector. One end of the cable is connected to the motherboard. The other end is connected to any drive that has a SATA data connector.
Floppy Data Cables
The floppy drive data cable has a 34-pin connector. Like the PATA data cable, the floppy drive data cable has a stripe to denote the location of pin 1. A floppy drive cable usually has three 34-pin connectors. One connector at the end of the cable connects to the motherboard. The other two connectors connect to drives. If multiple floppy drives are installed, the A: drive connects to the end connector. The B: drive connects to the middle connector.
Plug the floppy drive data cable into the drive with the pin 1 indicator on the cable aligned to the pin 1 indicator on the drive connector. Motherboards have one floppy drive controller, providing support for a maximum of two floppy drives.
NOTE: If pin 1 on the floppy drive data cable is not aligned with pin 1 on the drive connector, the floppy drive does not function. This misalignment does not damage the drive, but the drive activity light displays continuously. To fix this problem, turn off the computer and reconnect the data cable so that pin 1 on the cable and pin 1 on the connector are aligned. Reboot the computer.
Follow these steps for data cable installation:
Plug the motherboard end of the PATA cable into the motherboard socket. [Figure 1]
Plug the connector at the far end of the PATA cable into the optical drive. [Figure 2]
Plug one end of the SATA cable into the motherboard socket. [Figure 3]
Plug the other end of the SATA cable into the HDD. [Figure 4]
Plug the motherboard end of the FDD cable into the motherboard socket. [Figure 5]
Plug the connector at the far end of the FDD cable into the floppy drive. [Figure 6]
Now that all the internal components have been installed and connected to the motherboard and power supply, the side panels are re-attached to the computer case. The next step is to connect the cables for all computer peripherals and the power cable.
After completing this section, you will meet these objectives:
Re-attach the side panels to the case.
Connect external cables to the computer.
Most computer cases have two panels, one on each side. Some computer cases have one three-sided cover that slides down over the case frame.
When the cover is in place, make sure that it is secured at all screw locations. Some computer cases use screws that are inserted with a screwdriver. Other cases have knob-type screws that can be tightened by hand.
If you are unsure about how to remove or replace the computer case, refer to the documentation or website of the manufacturer for more information.
CAUTION: Handle case parts with care. Some computer case covers have sharp or jagged edges.
After the case panels have been re-attached, connect the cables to the back of the computer. Here are some common external cable connections:
Monitor
Keyboard
Mouse
USB
Ethernet
Power
When attaching cables, ensure that they are connected to the correct locations on the computer. For example, some mouse and keyboard cables use the same type of PS/2 connector.
CAUTION: When attaching cables, never force a connection.
NOTE: Plug in the power cable after you have connected all other cables.
Follow these steps for external cable installation:
Attach the monitor cable to the video port. [Figure 1]
Secure the cable by tightening the screws on the connector.
Plug the keyboard cable into the PS/2 keyboard port. [Figure 2]
Plug the mouse cable into the PS/2 mouse port. [Figure 3]
Plug the USB cable into a USB port. [Figure 4]
Plug the network cable into the network port. [Figure 5]
Connect the wireless antenna to the antenna connector. [Figure 6]
Plug the power cable into the power supply. [Figure 7]
Figure 8 shows all of the external cables plugged into the back of the computer.
When the computer is booted, the basic input/output system (BIOS) performs a check on all of the internal components. This check is called a power-on self test (POST).
After completing this section, you will meet these objectives:
Identify beep codes.
Describe BIOS setup.
POST checks to see that all of the hardware in the computer is operating correctly. If a device is malfunctioning, an error or a beep code alerts the technician that there is a problem. Typically, a single beep denotes that the computer is functioning properly. If there is a hardware problem, the computer might emit a series of beeps. Each BIOS manufacturer uses different codes to indicate hardware problems. Figure 1 shows a sample chart of beep codes. The beep codes for your computer might be different. Consult the motherboard documentation to view beep codes for your computer.
The BIOS contains a setup program used to configure settings for hardware devices. The configuration data is saved to a special memory chip called a Complementary Metal Oxide Semiconductor (CMOS), as shown in Figure 1. CMOS is maintained by the battery in the computer. If this battery dies, all BIOS setup configuration data will be lost. If this occurs, replace the battery and reconfigure the BIOS settings.
To enter the BIOS setup program, you must press the proper key or key sequence during POST. Most computers use the DEL key. Your computer might use another key or combination of keys.
Figure 2 shows an example of a BIOS setup program. Here are some common BIOS setup menu options:
Main – System time, date, HDD type, etc.
Advanced – Infrared port settings, parallel port settings, etc.
Security – Password settings to setup utility
Others – Low battery alarm, system beep, etc.
Boot – Boot order of the computer
Exit – Setup utility exit
This chapter detailed the steps used to assemble a computer and to boot the system for the first time. These are some important points to remember:
Computer cases come in a variety of sizes and configurations. Many of the components of the computer must match the form factor of the case.
The CPU is installed on the motherboard with a heat sink/fan assembly.
RAM is installed in RAM slots found on the motherboard.
Adapter cards are installed in PCI and PCIe expansion slots found on the motherboard.
Hard disk drives are installed in 3.5-inch drive bays located inside the case.
Optical drives are installed in 5.25-inch drive bays that can be accessed from outside the case.
Floppy drives are installed in 3.5-inch drive bays that can be accessed from outside the case.
Power supply cables are connected to all drives and the motherboard.
Internal data cables transfer data to all drives.
External cables connect peripheral devices to the computer.
Beep codes signify when hardware malfunctions.
The BIOS setup program is used to display information about the computer components and allows the user to change system settings.
Chapter 4
This chapter introduces preventive maintenance and the troubleshooting process. Preventive maintenance is a regular and systematic inspection, cleaning, and replacement of worn parts, materials, and systems. Preventive maintenance helps to prevent failure of parts, materials, and systems by ensuring that they are in good working condition. Troubleshooting is a systematic approach to locating the cause of a fault in a computer system. With fewer faults, there is less troubleshooting to do, thus saving an organization time and money.
Troubleshooting is a learned skill. Not all troubleshooting processes are the same, and technicians tend to refine their own troubleshooting skills based on knowledge and personal experience. Use the guidelines in this chapter as a starting point to help develop your troubleshooting skills. Although each situation is different, the process described in this chapter will help you to determine your course of action when you are trying to solve a technical problem for a customer.
After completing this chapter, you will meet these objectives:
Explain the purpose of preventive maintenance.
Identify the steps of the troubleshooting process.
Preventive maintenance reduces the probability of hardware or software problems by systematically and periodically checking hardware and software to ensure proper operation.
Hardware
Check the condition of cables, components, and peripherals. Clean components to reduce the likelihood of overheating. Repair or replace any components that show signs of abuse or excess wear. Use the tasks listed in Figure 1 as a guide to create a hardware maintenance program.
What additional hardware maintenance tasks can you add to the list?
Software
Verify that installed software is current. Follow the policies of the organization when installing security updates, operating system updates, and program updates. Many organizations do not allow updates until extensive testing has been completed. This testing is done to confirm that the update will not cause problems with the operating system and software. Use the tasks listed in Figure 2 as a guide to create a software maintenance schedule that fits the needs of your computer equipment.
What other software maintenance tasks can you add to the list?
Benefits
Be proactive in computer equipment maintenance and data protection. By performing regular maintenance routines, you can reduce potential hardware and software problems. Regular maintenance routines reduce computer downtime and repair costs.
A preventive maintenance plan is developed based on the needs of the equipment. A computer exposed to a dusty environment, such as a construction site, needs more attention than equipment in an office environment. High-traffic networks, such as a school network, might require additional scanning and removal of malicious software or unwanted files. Document the routine maintenance tasks that must be performed on the computer equipment and the frequency of each task. This list of tasks can then be used to create a maintenance program.
Some benefits of preventive maintenance are listed in Figure 3. Can you think of any other benefits that preventive maintenance provides?
Troubleshooting requires an organized and logical approach to problems with computers and other components. A logical approach to troubleshooting allows you to eliminate variables in a systematic order. Asking the right questions, testing the right hardware, and examining the right data helps you understand the problem. This helps you form a proposed solution to try.
Troubleshooting is a skill that you will refine over time. Each time you solve another problem, you will increase your troubleshooting skills by gaining more experience. You will learn how and when to combine, as well as skip, steps to reach a solution quickly. The troubleshooting process is a guideline that can be modified to fit your needs.
In this section, you will learn an approach to problem solving that can be applied to both hardware and software. Many of the steps can also be applied to problem solving in other work-related areas.
NOTE: The term customer, as used in this course, is any user that requires technical computer assistance.
After completing this section, you will meet these objectives:
Explain the purpose of data protection.
Identify the problem.
Establish a theory of probable causes.
Test the theory to determine an exact cause.
Establish a plan of action to resolve the problem and implement the solution.
Verify full system functionality, and if applicable, implement preventive measures.
Document findings, actions and outcomes.
Before you begin troubleshooting problems, always follow the necessary precautions to protect data on a computer. Some repairs, such as replacing a hard drive or reinstalling an operating system, might put the data on the computer at risk. Make sure that you do everything possible to prevent data loss while attempting repairs.
CAUTION: Although data protection is not one of the six troubleshooting steps, you must protect data before beginning any work on a customer's computer. If your work results in data loss for the customer, you or your company could be held liable.
Data Backup
A data backup is a copy of the data on a computer hard drive that is saved to media such as a CD, DVD, or tape drive. In an organization, backups are routinely done on a daily, weekly, and monthly basis.
If you are unsure that a backup has been done, do not attempt any troubleshooting activities until you check with the customer. Here is a list of items to verify with the customer about data backups:
Date of the last backup
Contents of the backup
Data integrity of the backup
Availability of all backup media for a data restore
If the customer does not have a current backup and you are not able to create one, you should ask the customer to sign a liability release form. A liability release form should contain at least the following information:
Permission to work on the computer without a current backup available
Release from liability if data is lost or corrupted
Description of the work to be performed
During the troubleshooting process, gather as much information from the customer as possible. The customer should provide you with the basic facts about the problem. Figure 1 lists some of the important information to gather from the customer.
Conversation Etiquette
When you are talking to the customer, you should follow these guidelines:
Ask direct questions to gather information.
Do not use industry jargon when talking to customers.
Do not talk down to the customer.
Do not insult the customer.
Do not accuse the customer of causing the problem.
By communicating effectively, you will be able to elicit the most relevant information about the problem from the customer.
Open-Ended Questions
Open-ended questions are used to obtain general information. Open-ended questions allow customers to explain the details of the problem in their own words. Figure 2 shows some examples of open-ended questions.
Closed-Ended Questions
Based on the information from the customer, you can proceed with closed-ended questions. Closed-ended questions generally require a "yes" or "no" answer. These questions are intended to get the most relevant information in the shortest time possible. Figure 3 shows some examples of closed-ended questions.
Documenting Responses
Document the information obtained from the customer in the work order and in the repair journal. Write down anything that you think might be important for you or another technician. Often, the small details can lead to the solution of a difficult or complicated problem. It is now time to verify the customer's description of the problem by gathering data from the computer.
Event Viewer
When system, user, or software errors occur on a computer, the Event Viewer is updated with information about the errors. The Event Viewer application shown in Figure 4 records the following information about the problem:
What problem occurred
Date and time of the problem
Severity of the problem
Source of the problem
Event ID number
Which user was logged in when the problem occurred
Although the Event Viewer lists details about the error, you might need to further research the solution.
Device Manager
The Device Manager shown in Figure 5 displays all of the devices that are configured on a computer. Any device that the operating system determines to be acting incorrectly is flagged with an error icon. This type of error has a yellow circle with an exclamation point (!). If a device is disabled, it is flagged with a red circle and an "X". A yellow question mark (?) indicates that the hardware is not functioning properly because the system does not know which driver to install for the hardware.
Beep Codes
Each BIOS manufacturer has a unique beep sequence for hardware failures. When troubleshooting, power on the computer and listen. As the system proceeds through the POST, most computers emit one beep to indicate that the system is booting properly. If there is an error, you might hear multiple beeps. Document the beep code sequence, and research the code to determine the specific hardware failure.
BIOS Information
If the computer boots and stops after the POST, investigate the BIOS settings to determine where to find the problem. A device might not be detected or configured properly. Refer to the motherboard manual to make sure that the BIOS settings are accurate.
Diagnostic Tools
Conduct research to determine which software is available to help diagnose and solve problems. There are many programs available that can help you troubleshoot hardware. Often, manufacturers of system hardware provide diagnostic tools of their own. For instance, a hard drive manufacturer, might provide a tool that you can use to boot the computer and diagnose why the hard drive does not boot Windows.
The second step in the troubleshooting process is to establish a theory of probable causes. First, create a list of the most common reasons why the error would occur. Even though the customer may think that there is a major problem, start with the obvious issues before moving to more complex diagnoses. List the easiest or most obvious causes at the top with the more complex causes at the bottom. You will test each of these causes in the next steps of the troubleshooting process.
The next step in the troubleshooting process is to determine an exact cause. You determine an exact cause by testing your theories of probable causes one at a time, starting with the quickest and easiest. Figure 1 identifies some common quick tests. After identifying an exact cause of the problem, determine the steps to resolve the problem. As you become more experienced at troubleshooting computers, you will work through the steps in the process faster. For now, practice each step to better understand the troubleshooting process.
If the exact cause of the problem has not been determined after you have tested all your theories, establish a new theory of probable causes and test it. If necessary, escalate the problem to a technician with more experience. Before you escalate, document each test that you try. Information about the tests is vital if the problem needs to be escalated to another technician, as shown in Figure 2.
After you have determined the exact cause of the problem, establish a plan of action to resolve the problem and implement the solution. Sometimes quick procedures can determine the exact cause of the problem or even correct the problem. If a quick procedure does correct the problem, you can go to step 5 to verify the solution and full system functionality. If a quick procedure does not correct the problem, you might need to research the problem further to establish the exact cause.
Evaluate the problem and research possible solutions. Figure 1 lists possible research locations. Divide larger problems into smaller problems that can be analyzed and solved individually. Prioritize solutions starting with the easiest and fastest to implement. Create a list of possible solutions and implement them one at a time. If you implement a possible solution and it does not work, reverse the solution and try another.
After the repairs to the computer have been completed, continue the troubleshooting process by verifying full system functionality and implementing any preventive measures if needed. Verifying full system functionality confirms that you have solved the original problem and ensures that you have not created another problem while repairing the computer. Whenever possible, have the customer verify the solution and system functionality.
After the repairs to the computer have been completed, finish the troubleshooting process by closing with the customer. Communicate the problem and the solution to the customer verbally and in all documentation. Figure 1 shows the steps to be taken when you have finished a repair and are closing with the customer.
Verify the solution with the customer. If the customer is available, demonstrate how the solution has corrected the computer problem. Have the customer test the solution and try to reproduce the problem. When the customer can verify that the problem has been resolved, you can complete the documentation for the repair in the work order and in your journal. The documentation should include the following information:
Description of the problem
Steps to resolve the problem
Components used in the repair
This chapter discussed the concepts of preventive maintenance and the troubleshooting process.
Regular preventive maintenance reduces hardware and software problems.
Before beginning any repair, back up the data on a computer.
The troubleshooting process is a guideline to help you solve computer problems in an efficient manner.
Document everything that you try, even if it fails. The documentation that you create will become a useful resource for you and other technicians.
Chapter 5
The operating system (OS) controls almost all functions on a computer. In this chapter, you will learn about the components, functions, and terminology related to the Windows 2000, Windows XP, and Windows Vista operating systems.
After completing this chapter, you will meet these objectives:
Explain the purpose of an operating system.
Describe and compare operating systems to include purpose, limitations, and compatibilities.
Determine the operating system based on customer needs.
Install an operating system.
Navigate a Graphical User Interface (GUI).
Identify and apply common preventive maintenance techniques for operating systems.
Troubleshoot operating systems.
All computers rely on an OS to provide the interface for interaction between users, applications, and hardware. The OS boots the computer and manages the file system. Almost all modern operating systems can support more than one user, task, or CPU.
After completing this section, you will meet these objectives:
Describe the characteristics of modern operating systems.
Explain operating system concepts.
Regardless of the size and complexity of the computer and the operating system, all operating systems perform the same four basic functions. Operating systems control hardware access, manage files and folders, provide a user interface, and manage applications.
Control Hardware Access
The operating system manages the interaction between applications and the hardware. To access and communicate with the hardware, the operating system installs a device driver for each hardware component. A device driver is a small program written by the hardware manufacturer and supplied with the hardware component. When the hardware device is installed, the device driver is also installed, allowing the OS to communicate with the hardware component.
The process of assigning system resources and installing drivers can be performed with Plug and Play (PnP). The PnP process was introduced in Windows 95 to simplify the installation of new hardware. All modern operating systems are PnP-compatible. With PnP, the operating system automatically detects the PnP-compatible hardware and installs the driver for that component. The operating system then configures the device and updates the registry, which is a database that contains all the information about the computer.
NOTE: The registry contains information about applications, users, hardware, network settings, and file types.
File and Folder Management
The operating system creates a file structure on the hard disk drive to allow data to be stored. A file is a block of related data that is given a single name and treated as a single unit. Program and data files are grouped together in a directory. The files and directories are organized for easy retrieval and use. Directories can be kept inside other directories. These nested directories are referred to as subdirectories. Directories are called folders in Windows operating systems, and subdirectories are called subfolders.
User Interface
The operating system enables the user to interact with software and hardware. There are two types of user interfaces:
Command Line Interface (CLI) – The user types commands at a prompt, as shown in Figure 1.
Graphical User Interface (GUI) – The user interacts with menus and icons, as shown in Figure 2.
Most operating systems, such as Windows 2000 and Windows XP, include both a GUI and a CLI.
Application Management
The operating system locates an application and loads it into the RAM of the computer. Applications are software programs, such as word processors, databases, spreadsheets, games, and many other applications. The operating system ensures that each application has adequate system resources.
An Application Programming Interface (API) is a set of guidelines used by programmers to ensure that the application they are developing is compatible with an operating system. Here are two examples of APIs:
Open Graphics Library (OpenGL) – Cross-platform standard specification for multimedia graphics
DirectX – Collection of APIs related to multimedia tasks for Microsoft Windows
To understand the capabilities of an operating system, it is important to understand some basic terms. The following terms are often used when comparing operating systems:
Multi-user – Two or more users can work with programs and share peripheral devices, such as printers, at the same time.
Multi-tasking – The computer is capable of operating multiple applications at the same time.
Multi-processing – The computer can have two or more central processing units (CPUs) that programs share.
Multi-threading – A program can be broken into smaller parts that can be loaded as needed by the operating system. Multi-threading allows individual programs to be multi-tasked.
Almost all modern operating systems are multi-user and multi-tasking, and they support multi-processing and multi-threading.
Modes of Operation
All modern CPUs can run in different modes of operation. The mode of operation refers to the capability of the CPU and the operating environment. The mode of operation determines how the CPU manages applications and memory. Figure 1 shows an example of the logical memory allocation. The four common modes of operation are real mode, protected mode, virtual real mode, and compatible mode.
Real Mode
A CPU that operates in real mode can only execute one program at a time, and it can only address 1 MB of system memory. Although all modern processors have real mode available, it is only used by DOS and DOS applications in old operating systems or by 16-bit operating environments, such as Windows 3.x.
Protected Mode
A CPU that operates in protected mode has access to all of the memory in the computer, including virtual memory. Virtual memory is hard disk space that is used to emulate RAM. Operating systems that use protected mode can manage multiple programs simultaneously. Protected mode provides 32-bit access to memory, drivers, and transfers between input and output (I/O) devices. Protected mode is used by 32-bit operating systems, such as Windows 2000 or Windows XP. In protected mode, applications are protected from using the memory reserved for another application that is currently running.
Virtual Real Mode
A CPU that operates in virtual real mode allows a real-mode application to run within a protected-mode operating system. This can be demonstrated when a DOS application runs in a 32-bit operating system, such as Windows XP. Figure 2 is a chart of some common DOS commands that can still be used in modern operating systems, such as Windows XP.
Compatibility Mode
Compatibility mode creates the environment of an earlier operating system for applications that are not compatible with the current operating system. As an example, an application that checks the version of the operating system might be written for Windows NT and require a particular service pack. Compatibility mode can create the proper environment or version of the operating system to allow the application to run as if it is in the intended environment.
Although Windows Vista is highly compatible with previous versions of Windows, two particularly useful features are available. The first feature is Windows XP Service Pack 2 (SP2) compatibility mode. This allows applications that are not compatible with Windows Vista to be executed as if the operating system were Windows XP SP2. The second feature is a method to override the User Account Control (UAC).This allows an application to be run even if the user does not have the required administrative privileges.
32-bit vs. 64-bit
There are three main differences between 32-bit and 64-bit operating systems. A 32-bit operating system, such as Windows XP Professional, is capable of addressing only 4 GB of RAM, while a 64-bit operating system can address more than 128 GB of RAM. Memory management is also different between these two types of operating systems, resulting in enhanced performance of 64-bit programs. A 64-bit operating system, such as Windows Vista 64-bit, has additional security features such as Kernel Patch Protection and mandatory Driver Signing. With Kernel Patch Protection, third-party drivers cannot modify the kernel. With mandatory Driver Signing, unsigned drivers cannot be used.
Processor Architecture
There are two common architectures used by CPUs to process data: x86 (32-bit architecture) and x64 (64-bit architecture). x86 uses a Complex Instruction Set Computer (CISC) architecture to process multiple instructions with a single request. Registers are storage areas used by the CPU when performing calculations. x86 processors use fewer registers than x64 processors. x64 architecture is backward compatible with x86 and adds additional registers specifically for instructions that use a 64-bit address space. The additional registers of the x64 architecture allow the computer to process much more complex instructions at a much higher rate.
A technician might be asked to choose and install an operating system for a customer. The type of OS selected depends on the customer's requirements for the computer. There are two distinct types of operating systems: desktop operating systems and network operating systems. A desktop operating system is intended for use in a Small Office/Home Office (SOHO) with a limited number of users. A Network Operating System (NOS) is designed for a corporate environment serving multiple users with a wide range of needs.
After completing this section, you will meet these objectives:
Describe desktop operating systems.
Describe network operating systems.
A desktop OS has the following characteristics:
Supports a single user
Runs single-user applications
Shares files and folders on a small network with limited security
In the current software market, the most commonly used desktop operating systems fall into three groups: Microsoft Windows, Apple Mac OS, and UNIX/Linux.
Microsoft Windows
Windows is one of the most popular operating systems today. The following products are desktop versions of the Microsoft Windows operating systems:
Windows XP Professional – Used on most computers that will connect to a Windows Server on a network
Windows XP Home Edition – Used on home computers and has very limited security
Windows XP Media Center – Used on entertainment computers for viewing movies and listening to music
Windows XP Tablet PC Edition – Used for tablet PCs
Windows XP 64-bit Edition – Used for computers with 64-bit processors
Windows 2000 Professional – Older Windows operating system that has been replaced by Windows XP Professional
Windows Vista Home Basic – Used on home computers for basic computing
Windows Vista Home Premium – Used on home computers to expand personal productivity and digital entertainment beyond the basics
Windows Vista Business – Used on small business computers for enhanced security and enhanced mobility technology
Windows Vista Ultimate – Used on computers to combine all the needs of both home and business users
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Apple Mac OS
Apple computers are proprietary and use an operating system called Mac OS. Mac OS is designed to be a user-friendly GUI operating system. Current versions of Mac OS are now based on a customized version of UNIX.
UNIX/Linux
UNIX, which was introduced in the late 1960s, is one of the oldest operating systems. There are many different versions of UNIX today. One of the most recent is the extremely popular Linux. Linux was developed by Linus Torvalds in 1991, and it is designed as an open-source operating system. Open-source programs allow the source code to be distributed and changed by anyone as a free download or from developers at a much lower cost than other operating systems.
NOTE: In this course, all command paths refer to Windows XP unless otherwise noted.
A network OS has the following characteristics:
Supports multiple users
Runs multi-user applications
Is robust and redundant
Provides increased security compared to desktop operating systems
These are the most common network operating systems:
Microsoft Windows – Network operating systems offered by Microsoft are Windows 2000 Server, Windows Server 2003, and Windows Server 2008. Windows Server operating systems use a central database called Active Directory to manage network resources.
Novell NetWare – Novell NetWare was the first OS to meet network OS requirements and enjoy widespread deployment in PC-based Local Area Networks (LANs) back in the 1980s.
Linux – Linux operating systems include Red Hat, Caldera, SUSE, Debian, Fedora, Ubuntu, and Slackware.
UNIX – Various corporations offer proprietary operating systems based on UNIX.
To select the proper operating system to meet the requirements of your customer, you need to understand how the customer wants to use the computer. The operating system that you recommend should be compatible with any applications that will be used and should support all hardware that is installed in the computer. If the computer will be attached to a network, the new operating system should also be compatible with other operating systems on the network.
After completing this section, you will meet these objectives:
Identify applications and environments that are compatible with an operating system.
Determine minimum hardware requirements and compatibility with the OS platform.
An operating system should be compatible with all applications that are installed on a computer. Before recommending an OS to your customer, investigate the types of applications that your customer will be using. If the computer will be part of a network, the operating system must also be compatible with the operating systems of the other computers in the network. The network type determines which operating systems are compatible. Microsoft Windows networks can have multiple computers using different versions of Microsoft operating systems. These are some guidelines that will help you determine the best operating system for your customer:
Does the computer have “off-the-shelf” applications or customized applications that were programmed specifically for this customer? If the customer will be using a customized application, the programmer of that application will specify which operating system is compatible with it. Most off-the-shelf applications specify a list of compatible operating systems on the outside of the application package.
Are the applications programmed for a single user or multiple users? This information helps you decide whether to recommend a desktop OS or a network OS. If the computer will be connected to a network, make sure to recommend the same OS platform that the other computers on the network use.
Are any data files shared with other computers, such as a laptop or home computer? To ensure compatibility of file formats, recommend the same OS platform that the other data file-sharing computers use.
As an example, your customer has a Windows network installed and wants to add more computers to the network. In this case, you should recommend a Windows OS for the new computers. If the customer does not have any existing computer equipment, the choice of available OS platforms increases. To make an OS recommendation, you must review budget constraints, learn how the computer will be used, and determine which types of applications will be installed.
Operating systems have minimum hardware requirements that must be met for the OS to install and function correctly. Figure 1 and Figure 2 provide a chart of the minimum hardware requirements and features for the various Windows operating systems.
Identify the equipment that your customer has in place. If hardware upgrades are necessary to meet the minimum requirements for an OS, conduct a cost analysis to determine the best course of action. In some cases, it might be less expensive for the customer to purchase a new computer than to upgrade the current system. In other cases, it might be cost-effective to upgrade one or more of the following components:
RAM
Hard disk drive
CPU
Video adapter card
NOTE: In some cases, the application requirements might exceed the hardware requirements of the operating system. For the application to function properly, it is necessary to satisfy the additional requirements.
After you have determined the minimum hardware requirements for an OS, ensure that all hardware in the computer is compatible with the operating system that you have selected for your customer.
Hardware Compatibility List
Most operating systems have a Hardware Compatibility List (HCL) that can be found on the manufacturer's website, as shown in Figure 3. These lists provide a detailed inventory of hardware that has been tested and is known to work with the operating system. If any of your customer’s existing hardware is not on the list, those components might need to be upgraded to match components on the HCL.
NOTE: An HCL might not be continuously maintained and therefore might not be a comprehensive reference.
As a technician, you might have to perform a clean installation of an operating system. Perform a clean install in the following situations:
When a computer is passed from one employee to another
When the operating system is corrupted
When a new replacement hard drive is installed in a computer
After completing this section, you will meet these objectives:
Identify hard drive setup procedures.
Prepare the hard drive.
Install the operating system using default settings.
Create user accounts.
Complete the installation.
Describe custom installation options.
Identify the boot sequence files and Registry files.
Describe how to manipulate operating system files.
Describe directory structures.
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The installation and initial booting of the operating system is called the operating system setup. Although it is possible to install an operating system over a network from a server or from a local hard drive, the most common installation method is with CDs and DVDs. To install an OS from a CD or DVD, first configure the BIOS setup to boot the system from the CD or DVD.
Partitioning and Formatting
Before installing an operating system on a hard drive, the hard drive must be partitioned and formatted. When a hard drive is partitioned, it is logically divided into one or more areas. When a hard drive is formatted, the partitions are prepared to hold files and applications. During the installation phase, most operating systems automatically partition and format the hard drive. A technician should understand the process relating to hard drive setup. The following terms are used when referring to hard drive setup:
Primary partition – This partition is usually the first partition. A primary partition cannot be subdivided into smaller sections. There can be up to four partitions per hard drive.
Active partition – This partition is the partition used by the operating system to boot the computer. Only one primary partition can be marked active.
Extended partition – This partition normally uses the remaining free space on a hard drive or takes the place of a primary partition. There can be only one extended partition per hard drive, and it can be subdivided into smaller sections called logical drives.
Logical drive – This drive is a section of an extended partition that can be used to separate information for administrative purposes.
Formatting – This process prepares a file system in a partition for files to be stored.
Sector – A sector contains a fixed number of bytes, generally at least 512.
Cluster – A cluster is also called a file allocation unit. It is the smallest unit of space used for storing data. It is made up of one or more sectors.
Track – A track is one complete circle of data on one side of a hard drive platter. A track is broken into groups of sectors.
Cylinder – A cylinder is a stack of tracks lined up one on top of another to form a cylinder shape.
Drive mapping – Drive mapping is a letter assigned to a physical or logical drive.
A clean installation of an operating system proceeds as if the disk were brand new; there is no attempt to preserve any information that is currently on the hard drive. The first phase of the installation process entails partitioning and formatting the hard drive. This process prepares the disk to accept the file system. The file system provides the directory structure that organizes the user's operating system, application, configuration, and data files.
The Windows XP operating system can use one of two file systems:
File Allocation Table, 32-bit (FAT32) – A file system that can support partition sizes up to 2 TB or 2,048 GB. The FAT32 file system is supported by Windows 9.x, Windows Me, Windows 2000, and Windows XP.
New Technology File System (NTFS) – A file system that can support partition sizes up to 16 exabytes, in theory. NTFS incorporates more file system security features and extended attributes than the FAT file system.
Figure 1 shows the steps required to partition and format a drive in Windows XP. Click the Start button in the lower right corner to see the hard drive setup steps.
The Windows Vista operating system will automatically create a partition on the entire hard drive, format it for you, and begin installing Windows if you do not create your own partitions using the New option, as shown in Figure 2. If you decide to create and format your own partitions, the process is the same as Windows XP, except that Windows Vista does not provide a choice of file systems. NTFS formats the partition in which Windows Vista will be installed.
When installing Windows XP, as shown in Figure 1, the installation wizard gives the option to install using typical (default) settings or custom settings. Using the typical settings increases the likelihood of a successful installation. However, the user must still provide the following information during the setup:
Standards and formats that define currency and numerals
Text input language
Name of the user and company
Product key
Computer name
Administrator password
Date and time settings
Network settings
Domain or workgroup information
When a computer boots up with the Windows installation disc, the Windows XP installation starts with three options:
Setup XP – To run the setup and install the XP operating system, press ENTER.
Repair XP – To repair an installation, press R to open the Recovery Console. The Recovery Console is a troubleshooting tool. It can be used to create and format partitions and repair the boot sector or Master Boot Record. It can also perform basic file operations on operating system files and folders. The Recovery Console configures services and devices to start or not start the next time the computer boots up.
Quit – To quit Setup without installing Windows XP, press F3.
For this section, select the Setup XP option.
Windows setup searches for existing Windows installations. If no existing installation is found, you can perform a clean installation of Windows. If an existing installation is found, you have the option of performing a repair installation. A repair installation fixes the current installation using the original files from the Windows XP installation disc. Before performing a repair installation, back up any important files to a different physical location such as a second hard drive, CD, or USB storage device.
After a repair installation begins, Windows setup copies installation files to the hard drive and reboots. Following the reboot, a message to press any key to boot from CD appears. Do not press any keys at this time. Setup continues to install Windows as if it were a clean install, but any applications that you have installed and any settings that you have configured remains unchanged.
When a computer boots up with the Windows Vista installation disc, Windows Vista installation starts with three options:
Upgrade – Keep your files, settings, and programs and upgrade Windows. Also use this option to repair an installation.
Custom (advanced) – Install a clean copy of Windows, select where you want to install it, or make changes to disks and partitions.
Quit – To quit Setup, click the x in the Close box.
If no existing Windows installations are found, the Upgrade option is disabled, as shown in Figure 2.
An administrator account is automatically created when Windows XP is installed. The default administrator account is named "administrator". For security purposes, change this name as soon as possible. Use this privileged account to manage the computer only. Do not use it as a daily account. People have accidentally made drastic changes while using the administrator account instead of a regular user account. Attackers seek out the administrator account because it is so powerful.
Create a user account when prompted during the installation process. Unlike the administrator account, user accounts can be created at any time. A user account has fewer permissions than the computer administrator. For example, users may have the right to read, but not modify, a file.
After the Windows installation copies all of the necessary operating system files to the hard drive, the computer reboots and prompts you to log in for the first time.
You must register Windows XP. As shown in Figure 1, you must also complete the verification that ensures that you are using a legal copy of the OS. Doing so enables you to download patches and service packs. Performing this step requires a connection to the Internet.
Depending on the age of the media at the time of your installation, there might be updates to install. As shown in Figure 2, you can use the Microsoft Update Manager from the Start menu to scan for new software and to do the following:
Install all service packs.
Install all patches.
Start > All Programs > Accessories > System Tools > Windows Update
In Windows Vista, use the following path to access Windows Update:
Start > All Programs > Windows Update
You should also verify that all hardware is installed correctly. As shown in Figure 3, you can use Device Manager to locate problems and to install the correct or updated drivers using the following path:
Start > Control Panel > System > Hardware > Device Manager
In Device Manager, warning icons are represented by a yellow exclamation point or a red “X”. A yellow exclamation point represents a problem with the device. To view the problem description, right-click the device and select Properties. A red “X” represents a device that has been disabled. To enable the device, right-click the disabled device and select Enable. To open a category that is not yet expanded, click the plus (+) sign.
NOTE: When Windows detects a system error, Windows reporting displays a dialog box. If you choose to send the report, Microsoft Windows Error Reporting (WER) collects information about the application and the module involved in the error and sends the information to Microsoft.
Installing an operating system on a single computer takes time. Imagine the time it would take to install operating systems on multiple computers, one at a time, in a large organization. To simplify this activity, you can use the Microsoft System Preparation (Sysprep) tool to install and configure the same operating system on multiple computers. Sysprep prepares an operating system that will be used on computers with different hardware configurations. With Sysprep and a disk cloning application, technicians are able to quickly install an operating system, complete the last configuration steps for the OS setup, and install applications.
Disk Cloning
Disk cloning creates an image of a hard drive in a computer. Follow these steps for disk cloning:
Create a master installation on one computer. This master installation includes the operating system, software applications, and configuration settings that will be used by the other computers in the organization.
Run Sysprep.
Create a disk image of the configured computer using a third-party disk-cloning program.
Copy the disk image onto a server. When the destination computer is booted, a shortened version of the Windows setup program runs. The setup creates a new system security identifier (SID), installs drivers for hardware, creates user accounts, and configures network settings to finish the OS install.
Network Installation
Windows can also be installed over a network:
Prepare the computer by creating a FAT or FAT32 partition of at least 1.5 GB. You must also make the partition bootable and include a network client. You can also use a boot disk that contains a network client so that the computer can connect to a file server over the network.
Copy the Windows XP installation files (the I386 folder from the installation disc) to the network server and make sure to share the directory so that clients can connect and use the files.
Boot the computer and connect to the shared directory.
From the shared directory, run the setup program, WINNT.EXE. The setup program copies all of the installation files from the network share onto your hard drive. After the installation files have been copied, the installation continues much the same as if the installation were performed from a disc.
Recovery Disc
You can use a recovery disc when there has been a system failure and other recovery options have failed, such as booting in Safe Mode or booting a Last Known Good. An Automated System Recovery (ASR) set must be created before a recovery can be performed. Use the ASR Wizard in Backup to create the ASR set. The ASR Wizard creates a backup of the system state, services, and operating system components. The ASR Wizard also creates a file that contains information about your disks, the backup, and how to restore the backup.
To restore the ASR, press F2 after booting the Windows XP installation disc. ASR reads the set and restores the disks that are needed to start the computer. After the basic disk information has been restored, ASR installs a basic version of Windows and begins restoring the backup created by the ASR Wizard.
Factory Recovery Partition
Some computers that have Windows XP pre-installed from the factory contain a section of disk that is inaccessible to the user. This partition on the disk contains an image of the bootable partition, created when the computer was built. This partition is called a factory recovery partition and can be used to restore the computer to its original configuration. Occasionally, the option to reach this partition for restoration is hidden and a special key or key combination must be used when the computer is being started. The option to restore from the factory recovery partition can also be found in the BIOS of some computers. Contact the manufacturer to find out how you can access the partition and restore the original configuration of the computer.
You should know the process that Windows XP uses when booting. Understanding these steps can help you to troubleshoot boot problems. Figure 1 shows the boot sequence for Windows XP.
Windows XP Boot Process
To begin the boot process, you first turn on the computer, which is called a cold boot. The computer performs the Power On Self Test (POST). Because the video adapter has not yet been initialized, any errors that occur at this point in the boot process are reported by a series of audible tones, called beep codes.
After POST, the BIOS locates and reads the configuration settings that are stored in the CMOS. This configuration setting, called the boot device priority, is the order in which devices are checked to see if an operating system is located there. The boot device priority, as shown in Figure 2, is set in the BIOS and can be arranged in any order. The BIOS boots the computer using the first drive that contains an operating system.
One common boot order is floppy drive, CD-ROM drive, and then the hard drive. This order allows you to use removable media to boot the computer. The BIOS checks the floppy drive, the CD-ROM, and finally the hard drive for an operating system to boot the computer. Network drives, USB drives, and even removable magnetic media, such as CompactFlash or Secure Digital (SD) cards, can also be used in the boot order, depending on the capabilities of the motherboard. Some BIOS also have a boot device priority menu that can be accessed using a special key combination while the computer is starting but before the boot sequence begins. You can use this menu to choose the device that you want to boot, which is useful if multiple drives can boot the computer.
When the drive with the operating system is located, the BIOS locates the Master Boot Record (MBR). The MBR locates the operating system boot loader. For Windows XP, the boot loader is called NT Loader (NTLDR).
NTLDR and the Windows Boot Menu
At this point, NTLDR controls several installation steps. For instance, if more than one OS is present on the disk, BOOT.INI gives the user a chance to select which one to use. If there are no other operating systems, or if the user does not make a selection before the timer expires, the following steps occur:
NTLDR runs NTDETECT.COM to get information about the installed hardware.
NTLDR then uses the path specified in the BOOT.INI to find the boot partition.
NTLDR loads two files that make up the core of XP: NTOSKRNL.EXE and HAL.DLL.
NTLDR reads the Registry files, chooses a hardware profile, and loads the device drivers.
Windows Registry
The Windows Registry files are an important part of the Windows XP boot process. These files are recognized by their distinctive names, which begin with HKEY_, as shown in Figure 3, followed by the name of the portion of the operating system under their control. Every setting in Windows—from the background of the desktop and the color of the screen buttons to the licensing of applications—is stored in the Registry. When a user makes changes to the Control Panel settings, File Associations, System Policies, or installed software, the changes are stored in the Registry.
Each user has a unique section of the Registry. The Windows login process pulls system settings from the Registry to reconfigure the system to the state that it was in the last time that the user turned it on.
NT Kernel
At this point, the NT kernel, the heart of the Windows operating system, takes over. The name of this file is NTOSKRNL.EXE. It starts the login file called WINLOGON.EXE and displays the XP welcome screen.
NOTE: If a SCSI drive will boot the computer, Windows copies the NTBOOTDD.SYS file during installation. This file is not copied if SCSI drives are not being used.
After you have installed Windows XP, you might want to make changes to the configuration. The following applications are used extensively for post-installation diagnostics and modifications:
Msconfig – This boot configuration utility allows you to set the programs that run at startup and to edit configuration files. It also offers simplified control over Windows Services, as shown in Figure 1. Figure 2 shows Msconfig in Windows Vista.
Regedit – This application allows you to edit the registry, as shown in Figure 3.
Msinfo32 – This utility displays a complete system summary of your computer including hardware components and details, and installed software and settings, as shown in Figure 4.
Dxdiag – This utility shows details about all of the DirectX components and drivers that are installed in your computer, as shown in Figure 5. You can use this utility to ensure that DirectX is installed properly and configured correctly.
Cmd – This command opens a command window when it is entered in the Run… box, as shown in Figure 6. This is used to execute command line programs and utilities.
NOTE: REGEDT32.EXE was used with Windows NT. In Windows XP, and Windows Server 2003, the REGEDT32.EXE file is a shortcut to the REGEDIT.EXE command. In Windows XP, you can enter REGEDT32.EXE or REGEDIT.EXE; both commands run the same program.
CAUTION: Using REGEDT32.EXE or REGEDIT.EXE incorrectly might cause configuration problems that could require you to reinstall the operating system.
Startup Modes
You can boot Windows in one of many different modes. Pressing the F8 key during the boot process opens the Windows Advanced Startup Options menu, which allows you to select how to boot Windows. The following startup options are commonly used:
Safe Mode – Starts Windows but only loads drivers for basic components, such as the keyboard and display.
Safe Mode with Networking Support – Starts Windows identically to Safe Mode and also loads the drivers for network components.
Safe Mode with Command Prompt – Starts Windows and loads the command prompt instead of the GUI.
Last Known Good Configuration – Enables a user to load the configuration settings of Windows that were used the last time that Windows started successfully . It does this by accessing a copy of the registry that is created for this purpose.
NOTE: Last Known Good Configuration is not useful unless it is applied immediately after a failure occurs. If the machine is restarted and, despite its difficulties, manages to open Windows, the registry key for Last Known Good Configuration will probably be updated with the faulty information.
Lab
File Extensions and Attributes
In Windows, files are organized in a directory structure. The root level of the Windows partition is usually labeled drive C:\. Next, there is an initial set of standardized directories, called folders, for the operating system, applications, configuration information, and data files. Following the initial installation, users can install most applications and data in whichever directory they choose.
Files in the directory structure adhere to a Windows naming convention:
Maximum of 255 characters can be used.
Characters such as a slash or a backslash (/ \) are not allowed.
An extension of three or four letters is added to the filename to identify the file type.
Filenames are not case sensitive.
The following filename extensions are commonly used:
.doc – Microsoft Word
.txt – ASCII text only
.jpg – Graphics format
.ppt – Microsoft PowerPoint
.zip – Compression format
The directory structure maintains a set of attributes for each file that controls how the file can be viewed or altered. These are the most common file attributes:
R – The file is read-only.
A – The file will be archived the next time that the disk is backed up.
S – The file is marked as a system file, and a warning is given if an attempt is made to delete or modify the file.
H – The file is hidden in the directory display.
You can view the filenames, extensions, and attributes by entering the ATTRIB command in a DOS window, as shown in Figure 1. Use the following path:
Start > Run > Type cmd and Press Enter
In Windows Vista, use the following path:
Start > Start Search > Type cmd and Press Enter
Navigate to the folder that contains the file that you are interested in. Type ATTRIB followed by the file name. Use a wildcard such as *.* to view many files at once. The attributes of each file appear in the left column of the screen. To get information about the ATTRIB command, type the following at the command prompt:
ATTRIB/?
You can access the Windows equivalent of ATTRIB by right-clicking a file in Windows Explorer and choosing Properties.
NOTE: To see the properties of a file in Windows Explorer, you must first set Windows Explorer to Show Hidden Files. Use this path:
Right-click Start > Explore > Tools > Folder Options > View
In Windows Vista, use this path:
Right-click Start > Explore > Organize > Folder and Search Options > View
NTFS and FAT32
Windows XP and Windows 2000 use FAT32 and NTFS, while Windows Vista uses NTFS. Security is one of the most important differences between these file systems. NTFS can support more and larger files than FAT32 and provides more flexible security features for files and folders. Figures 2 and 3 show the file permission properties for FAT32 and NTFS.
To use the extra security advantages of NTFS, you can convert partitions from FAT32 to NTFS using the CONVERT.EXE utility. To restore an NTFS partition back to a FAT32 partition, reformat the partition and restore the data from a backup.
CAUTION: Before converting a file system, remember to back up the data.
The operating system provides a user interface that allows you to interact with the computer. There are two methods that you can use to navigate the file system and run applications within an operating system:
A Graphical User Interface (GUI) provides graphical representations (icons) of all of the files, folders, and programs on a computer. You manipulate these icons using a pointer that is controlled with a mouse or similar device. The pointer allows you to move icons by dragging and dropping, and execute programs by clicking.
A Command Line Interface (CLI) is text-based. You must type commands to manipulate files and execute programs.
After completing this section, you will meet these objectives:
Manipulate items on the desktop.
Explore Control Panel applets.
Explore Administrative Tools.
Install, navigate, and uninstall an application.
Describe upgrading operating systems.
After the operating system has been installed, the desktop can be customized to suit individual needs. A desktop on a computer is a graphical representation of a workspace. The desktop has icons, toolbars, and menus to manipulate files. The desktop can be customized with images, sounds, and colors to provide a more personalized look and feel. All of these customizable items together make up a theme. Windows Vista has a special theme called Aero, as shown in Figure 1. Aero is the default theme and has translucent window borders, numerous animations, and live icons that are thumbnail images of the contents of a file. Because of the advanced graphics needed, the Aero theme can only be used on computers that meet certain hardware requirements.
NOTE: Windows Vista Home Basic does not include the Aero theme.
In Windows Vista, a feature called the Sidebar, as shown in Figure 2, can also be personalized. The Sidebar is a graphical pane on the desktop that keeps small programs called gadgets organized. Gadgets are small applications such as games, sticky notes, or a clock. Gadgets, like interfaces to web information such as weather maps or contacts on a social networking site, can also be added.
Desktop Properties
To customize the Windows XP GUI of your desktop, right-click the desktop and choose Properties. The Display Properties window, as shown in Figure 3, has five tabs: Themes, Desktop, Screen Saver, Appearance, and Settings. Click any of these tabs to customize your display settings. In Windows Vista, right-click the desktop and choose Personalize. The Personalization window, as shown in Figure 4, has seven links: Window Color and Appearance, Desktop Background, Screen Saver, Sounds, Mouse Pointers, Themes, and Display Settings. Click any of these links to customize your display settings.
Desktop Items
There are several items on the desktop that can be customized, such as the Taskbar and Recycle Bin. To customize any item, right-click the item and then choose Properties.
Start Menu
On the desktop, the Start menu is accessed by clicking the Start button. The Start menu, shown in Figure 5, displays all of the applications installed in the computer, a list of recently opened documents, and a listing of other elements, such as a search feature, help center, and system settings. The Start menu can also be customized. There are two styles of Start menu: XP and Classic. The XP-style Start menu is used throughout this course for demonstrating command sequences.
My Computer
To access the various drives installed in the computer, double-click the My Computer icon that appears on the desktop. To customize certain settings, right-click My Computer and choose Properties. Settings that can be customized include the following:
Computer name
Hardware settings
Virtual memory
Automatic updates
Remote access
NOTE: In Windows Vista, My Computer is called Computer. To customize certain settings, click the Start button then right-click Computer and choose Properties. Access installed drives in Windows Vista with the following path:
Start > Computer
Launching Applications
You can launch applications in several ways:
Click the application on the Start menu.
Double-click the application shortcut icon on the desktop.
Double-click the application executable file in My Computer.
Launch the application from the Run window or command line.
My Network Places
To view and configure network connections, right-click the My Network Places icon on the desktop. In My Network Places, you can connect to or disconnect from a network drive. Click Properties to configure existing network connections, such as a wired or wireless LAN connection.
NOTE: In Windows Vista, My Network Places is called Network.
Windows centralizes the settings for many features that control the behavior and appearance of the computer. These settings are categorized in applets, or small programs, found in the Control Panel, as shown in Figure 1. Adding or removing programs, changing network settings, and changing the security settings are some of the configuration options available in the Control Panel.
Control Panel Applets
The names of various applets in the Control Panel differ slightly depending on the version of Windows installed. In Windows XP, the icons are grouped into categories:
Appearance and Themes – applets that control the look of windows:
Display
Taskbar and Start menu
Folder options
Network and Internet Connections – applets that configure all of the connection types:
Internet options
Network connections
Add or Remove Programs – applet to add or remove programs and windows components safely
Sounds, Speech, and Audio Devices – applets that control all of the settings for sound:
Sounds and audio devices
Speech
Portable Media Devices
Performance and Maintenance – applets to find information about your computer or perform maintenance:
Administrative tools
Power options
Scheduled tasks
System
Printers and Other Hardware – applets to configure devices connected to your computer:
Game controllers
Keyboard
Mouse
Phone and modem options
Printers and faxes
Scanners and cameras
User Accounts – applets to configure options for users and their e-mail:
User accounts
Date, Time, Language, and Regional Options – applets to change settings based on your location and language:
Date and time
Regional and language options
Accessibility Options – wizard used to configure windows for vision, hearing, and mobility needs
Security Center – applet used to configure security settings for:
Internet options
Automatic updates
Windows firewall
Display Settings
You can change the display settings by using the Display Settings applet. Change the appearance of the desktop by modifying the resolution and color quality, as shown in Figure 2. You can change more advanced display settings, such as wallpaper, screen saver, power settings, and other options, with the following path:
Start > Control Panel > Display > Settings tab > Advanced
Use the following path in Windows Vista:
Start > Control Panel > Personalization > Display Settings > Advanced Settings button
Computer Management
The Computer Management console, shown in Figure 1, allows you to manage many aspects of both your computer and remote computers. The Computer Management console addresses three main areas of administration: System Tools, Storage, and Services and Applications. You must have administrative privileges to access the Computer Management console. To view the Computer Management console, use the following path:
Start > Control Panel > Administrative Tools > Computer Management
To view the Computer Management console for a remote computer, right-click Computer Management (Local) in the console tree and click Connect to another computer…. In the Another computer: box, type the name of the computer or click Browse… to find a computer you want to manage.
Device Manager
The Device Manager, shown in Figure 2, allows you to view all of the settings for devices in the computer. A common task for technicians is to view the values assigned for the IRQ, I/O address, and the DMA setting for all of the devices in the computer. To view the system resources in the Device Manager, use the following path:
Start > Control Panel > System > Hardware > Device Manager > View > Resources
In Windows Vista, use the following path:
Start > Control Panel > System > Device Manager > Continue > View > Resources
From the Device Manager, you can quickly view the properties of any device in the system by double-clicking the device name. You can view which version of the driver is installed in your computer, view driver file details, update a driver, or even roll back or uninstall a device driver. You can compare the driver version listed here with the version available from the website of your device manufacturer.
Task Manager
The Task Manager, shown in Figure 3, allows you to view all applications that are currently running and to close any applications that have stopped responding. The Task Manager allows you to monitor the performance of the CPU and virtual memory, view all processes that are currently running, and view information about the network connections. To view information in the Task Manager, use the following path:
CTRL-ALT-DEL > Task Manager
In Windows Vista, use the following path:
CTRL-ALT-DEL > Start Task Manager
Services
Services are executable programs that require little or no user input. Services can be set to run automatically when Windows starts, or manually when required. The Services console, shown in Figure 4, allows you to manage all of the services on your computer and remote computers. You can start, stop, or disable services. You can also change how a service starts, or define actions for the computer to perform automatically when a service fails. You must have administrative privileges to access the Services console. To view the Services console, use the following path:
Start > Control Panel > Administrative Tools > Services
To view the Services console for a remote computer, right-click Services (Local) in the console tree and click Connect to another computer In the Another computer: box, type the name of the computer or click Browse… to find a computer you want to manage.
Performance Monitor
The Performance Monitor console, shown in Figure 5, has two distinct parts: the System Monitor and Performance Logs and Alerts. The System Monitor displays real-time information about the processors, disks, memory, and network usage for your computer. You can easily summarize these activities through histograms, graphs, and reports.
Performance Logs and Alerts allow you to record the performance data and configure alerts. The alerts will notify you when a specified usage falls below or rises above a specified threshold. You can set alerts to create entries in the event log, send a network message, begin a performance log, run a specific program, or any combination of these. You must have administrative privileges to access the Performance Monitor console. To view the Performance Monitor console in Windows XP, use the following path:
Start > Control Panel > Administrative Tools > Performance
In Windows Vista, use the following path:
Start > Control Panel > Administrative Tools > Reliability and Performance Monitor > Continue
Event Viewer
The Event Viewer, shown in Figure 6, logs a history of events regarding applications, security, and the system. These log files are a valuable troubleshooting tool. To access the Event Viewer, use the following path:
Start > Control Panel > Administrative Tools > Event Viewer
In Windows Vista, use the following path:
Start > Control Panel > Administrative Tools > Event Viewer > Continue
MMC
The Microsoft Management console (MMC), shown in Figure 7, allows you to organize management tools, called snap-ins, in one location for easy administration. Web page links, tasks, ActiveX controls, and folders can also be added to the MMC. After you have configured an MMC, save it to keep all the tools and links in that MMC. You can create as many customized MMCs as needed, each with a different name. This is useful when multiple administrators manage different aspects of the same computer. Each administrator can have an individualized MMC for monitoring and configuring computer settings. You must have administrative privileges to access the MMC. To view the MMC in Windows XP, use the following path:
Start > Run > Type mmc and Press Enter
In Windows Vista, use the following path:
Start > Start Search > Type mmc and Press Enter
Remote Desktop
The Remote Desktop allows one computer to remotely take control of another computer. Remote technicians can use this troubleshooting feature to repair and upgrade computers. For Windows XP, Remote Desktop is available on Windows XP Professional only. To access the Remote Desktop in Windows XP Professional, use the following path:
Start > All Programs > Accessories > Communications > Remote Desktop Connection
In Windows Vista, use the following path:
Start > All Programs > Accessories > Remote Desktop Connection
Performance Settings
To enhance the performance of the operating system, you can change some of the settings that your computer uses, such as virtual memory configuration settings, which are shown in Figure 8. To change the virtual memory setting in Windows XP, use the following path:
Start > Control Panel > System > Advanced > Performance area > Settings button
In Windows Vista, use the following path:
Start > Control Panel > System > Advanced system settings > Continue > Advanced tab > Performance area > Settings button > Advanced
As a technician, you will be responsible for adding and removing software from your customers' computers. Most applications use an automatic installation process when an application CD is inserted in the optical drive. The installation process updates the Add or Remove Programs utility. The user is required to click through the installation wizard and provide information when requested.
Add or Remove Programs Applet
Microsoft recommends that users always use the Add or Remove Programs utility, as shown in Figure 1, when installing or removing applications. When you use the Add or Remove Programs utility to install an application, the utility tracks installation files so that the application can be uninstalled completely, if desired. To open the Add or Remove Programs applet in Windows XP, use the following path:
Start > Control Panel > Add or Remove Programs
In Windows Vista, use the following path:
Start > Control Panel > Programs and Features
Add an Application
If a program or application is not automatically installed when the CD is inserted, you can use the Add or Remove Programs applet to install the application in Windows XP, as shown in Figure 2. Click the Add New Programs button and select the location where the application is located. Windows installs the application for you. In Windows Vista, insert the CD or DVD, and the program installer should start. If the program does not start, browse the CD or DVD and run the "setup" or "install" file to begin installation.
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Athiacaepoalwitftttmpftitbdttp – ptfkstatiotp
Wpiuofi – PS/2
After the application is installed, the application can be started from the Start menu or a shortcut icon that the application installs on the desktop. Check the application to ensure that it is functioning properly. If there are problems with the application, make the repair or uninstall the application. Some applications, such as Microsoft Office, provide a repair option in the install process. You can use this function to try to correct a program that is not working properly.
Uninstall an Application
If an application is not uninstalled properly, you may be leaving files on the hard drive and unnecessary settings in the registry. This might not cause any problems, but it depletes available hard drive space, system resources, and the speed at which the registry is read. Figure 3 shows the Add or Remove Programs applet to use to uninstall programs in Windows XP. The wizard guides you through the software removal process and removes every file that was installed.
Sometimes it might be necessary to upgrade an operating system. Before upgrading the operating system, check the minimum requirements of the new operating system to ensure that the computer meets the minimum specifications. Check the HCL to ensure that the hardware is compatible with the new operating system. Back up all data before upgrading the operating system in case there is a problem with the installation.
The process of upgrading a computer system from Windows 2000 to Windows XP is quicker than performing a new installation of Windows XP. The Windows XP setup utility replaces the existing Windows 2000 files with Windows XP files during the upgrade process. However, existing applications and settings are saved.
Upgrading the Operating System to Windows XP
Insert the Windows XP disc into the optical drive to start the upgrade process. Select Start > Run.
In the Run box, where D is the drive letter for the optical drive, type D:\i386\winnt32 and press Enter. The Welcome to the Windows XP Setup Wizard displays.
Choose Upgrade to Windows XP and click Next. The License Agreement page displays.
Read the license agreement and click the button to accept this agreement.
Click Next. The Upgrading to the Windows XP NTFS File System page displays.
Follow the prompts and complete the upgrade. When the install is complete, the computer will restart.
NOTE: The Windows XP Setup Wizard might automatically start when the disc is inserted into the optical drive.
NOTE: Before you can upgrade from Windows XP to Windows Vista, you must install Windows XP Service Pack 2.
Upgrading the Operating System to Windows Vista
Insert the Windows Vista disc into the optical drive. The Set Up window appears.
Select Install Windows Vista.
You are prompted to download any important updates for Windows Vista.
Enter your Product Key and then agree to the End User License Agreement (EULA).
You are presented with two choices, Custom or Upgrade.
Click Upgrade and setup will begin copying installation files.
Follow the prompts and complete the upgrade. When the install is complete, the computer will restart.
In some cases, you cannot upgrade to a newer operating system. Figure 1 shows which Windows operating systems can be upgraded to other versions of Windows. If your operating system cannot be upgraded, you must perform a new installation.
When a new installation of Windows is needed, you can use the Windows User State Migration Tool (USMT) to migrate all of the current user files and settings to the new operating system. The USMT allows users to restore the configurations and customizations from their current computer to the newly installed Windows operating system. Download and install USMT from Microsoft to create a store of user files and settings onto a separate drive or partition. After the new operating system is installed, download and install USMT again to restore the user files and settings to the new operating system.
Preventive maintenance for an operating system includes organizing the system, defragmenting the hard drive, keeping applications current, removing unused applications, and checking the system for errors.
After completing this section, you will meet these objectives:
Create a preventive maintenance plan.
Schedule a task.
Back up the hard drive.
The goal of an operating system preventive maintenance plan is to avoid problems in the future. Perform preventive maintenance regularly, and record all actions taken and observations made. Some preventative maintenance should take place when it causes the least amount of disruption to the people who use the computers. This often means scheduling tasks at night, early in the morning, or over the weekend. There are also tools and techniques that can automate many preventive maintenance tasks.
Preventive Maintenance Planning
Preventive maintenance plans should include detailed information about the maintenance of all computers and network equipment, with emphasis on equipment that could impact the organization the most. Preventive maintenance includes the following important tasks:
Hard drive backup [Figure 1]
Hard drive defragmentation [Figure 2]
Updates to the operating system and applications [Figure 3]
Updates to antivirus and other protective software [Figure 4]
Hard drive error checking [Figure 5]
A preventive maintenance program that is designed to fix things before they break, and to solve small problems before they affect productivity, can provide the following benefits to users and organizations:
Decreased downtime
Improved performance
Improved reliability
Decreased repair costs
An additional part of preventive maintenance is documentation. A repair log helps you determine which equipment is the most or least reliable. It also provides a history of when a computer was last fixed, how it was fixed, and what the problem was.
Device Driver Updates
Manufacturers occasionally release new drivers to address issues with the current drivers. As a best practice, you should check for updated drivers regularly. Check for updated drivers when your hardware does not work properly or to prevent future problems. It is also important to update drivers that patch or correct security problems. Updating device drivers should be part of your preventive maintenance program to ensure that your drivers are always current. If a driver update does not work properly, use the Roll Back Driver feature to revert back to the previously installed driver.
Firmware Updates
Manufacturers occasionally release new firmware updates to address issues that might not be fixed with driver updates. Firmware updates are less common than driver updates. They can increase the speed of certain types of hardware, enable new features, or increase the stability of a product. Follow the manufacturer’s instructions carefully when performing a firmware update to avoid making the hardware unusable. Research the firmware updates completely because it might not be possible to revert to the original firmware. Checking for firmware updates should be part of your preventive maintenance program.
Operating System Updates
Microsoft releases updates to address security issues and other functionality problems. You can install individual updates manually from the Microsoft website or automatically using the Windows Automatic Update utility.
Downloads that contain multiple updates are known as service packs. A service pack usually contains all of the updates for an operating system. Installing a service pack is a good way to bring your operating system up to date quickly. Set a restore point and back up critical data prior to installing a service pack. Add operating system updates to your preventive maintenance program to ensure that your operating system has the latest functionality and security fixes.
Security
Security is an important aspect of your preventive maintenance program. Install virus and malware protection software and perform regular scans on your computer to help ensure that your computer remains free of malicious software. Use the Windows Malicious Software Removal Tool to check a computer for specific, prevalent malicious software. If an infection is found, the tool removes it. Each time a new version of the tool is available from Microsoft, download it and scan your computer for new threats. This should be a standard item in your preventive maintenance program along with regular updates to your antivirus and spyware removal tools.
Startup Programs
Some programs, such as antivirus scanners and spyware removal tools, do not automatically start when the computer boots up. To ensure that these programs run each time the computer is booted, add the program to the Startup folder of the Start menu. Many programs have switches to allow the program to perform a specific action, start up without being displayed, or go to the Windows Tray. Check the documentation to determine if your programs allow the use of special switches.
Some preventive maintenance consists of cleaning, inspecting, and doing minor repairs. Some preventive maintenance uses application tools that are either already in the operating system or can be loaded onto the user's hard drive. Most preventive maintenance applications can be set to run automatically according to a schedule.
Windows has the following utilities that launch tasks when you schedule them:
The DOS AT command launches tasks at a specified time using the CLI.
The Windows Task Scheduler launches tasks at a specified time using a GUI.
Information about the AT command is available at this path in Windows XP:
Start > Run > Type cmd and press Enter
Then type AT /? at the command line.
In Windows Vista, access the command line using the following path:
Start > Start Search > Type cmd and press Enter
Access the Windows Task Scheduler by following this path in Windows XP:
Start > All Programs > Accessories > System Tools > Scheduled Tasks
In Windows Vista, follow this path:
Start > All Programs > Accessories > System Tools > Task Scheduler
Both of these tools allow you to run a command once at a specific time or schedule a command to run on selected days or times. The Windows Task Scheduler, shown in Figure 1, is easier to learn and use than the AT command, especially when it comes to recurring tasks and deleting tasks already scheduled.
System Utilities
Several utilities included with DOS and Windows help maintain system integrity. Two utilities that are useful tools for preventive maintenance are:
ScanDisk or CHKDSK – ScanDisk (Windows 2000) and CHKDSK (Windows XP and Vista) check the integrity of files and folders and scan the hard disk surface for physical errors. Consider using ScanDisk or CHKDSK at least once a month and also whenever a sudden loss of power causes the system to shut down.
Defrag – As files increase in size, some data is written to the next available space on the disk. In time, data becomes fragmented, or spread all over the hard drive. It takes time to seek each section of the data. Defrag gathers the noncontiguous data into one place, making files run faster.
You can access both of these utilities by using this path in Windows XP:
Start > All Programs > Accessories > System Tools > Disk Defragmenter
In Windows Vista, use this path:
Start > Computer > right-click Drive x > Properties > Tools
Automatic Updates
If every maintenance task had to be scheduled every time it was run, repairing computers would be much harder than it is today. Fortunately, tools such as the Scheduled Task Wizard allow many functions to be automated. But how can you automate the update of software that has not been written?
Operating systems and applications are constantly being updated for security purposes and for added functionality. It is important that Microsoft and others provide an update service, as shown in Figure 2. The update service can scan the system for needed updates and then recommend what should be downloaded and installed. The update service can download and install updates as soon as they are available, or it can download updates as required, and install them when the computer is next rebooted. The Microsoft Update Wizard is available at this path in Windows XP:
Start > Control Panel > System > Automatic Updates
In Windows Vista, it is available at this path:
Start > Control Panel > Windows Update
Most antivirus software contains its own update facility. It can update both its application software and its database files automatically. This feature allows it to provide immediate protection as new threats develop.
Restore Point
An update can sometimes cause serious problems. Perhaps an older program is in the system that is not compatible with the current operating system. An automatic update might install code that works for most users but does not work with your system.
You can solve this problem by creating a restore point, which is an image of the computer settings. If the computer crashes or an update causes system problems, the computer can roll back to a previous configuration. You can use the Windows Restore Point utility, as shown in Figure 3, to create and revert to a restore point.
A technician should always create a restore point before updating or replacing the operating system. Restore points should also be created at the following times:
When an application is installed
When a driver is installed
NOTE: A restore point backs up drivers, system files, and registry settings but not application data.
To restore or create a restore point, use the following path:
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Start > All Programs > Accessories > System Tools > System Restore
Backup Status and Configuration
Windows Vista has the Backup Status and Configuration tool for backing up photos, music, email, and other types of user data. Backups can be set to run automatically at regular intervals. Back up your data to a drive other than the drive that contains the operating system. The Backup Status and Configuration tool is not used to back up system settings. Windows Vista Home Basic does not include the option to set automatic backups. To access the Backup Status and Configuration tool, use the following path:
Start > All Programs > Accessories > System Tools > Backup Status and Configuration
ERD and ASR
Windows 2000 offers the ability to create an emergency repair disk (ERD) that saves critical boot files and configuration information necessary to troubleshoot problems in Windows. Windows XP offers the same features with the Automated System Recovery (ASR) wizard. Although both ERD and ASR are powerful troubleshooting tools, they should never replace a good backup.
A recovery disc contains the essential files used to repair the system after a serious issue, such as a hard drive crash. The recovery disc can contain the original version of Windows, hardware drivers, and application software. When the recovery disc is used, the computer is restored to the original default configuration.
Just as the system restore points allow the restoration of OS configuration files, backup tools allow the recovery of data. You can use the Microsoft Backup Utility, shown in Figure 1, to perform back ups as required. It is important to establish a backup strategy that includes data recovery. The organization's requirements will determine how often the data must be backed up and the type of backup to perform.
It can take a long time to run a backup. If the backup strategy is followed carefully, it will not be necessary to back up every file at every backup. It is only necessary to make copies of the files that have changed since the last backup. For this reason, there are several different types of backups.
Normal Backup
A normal backup is also called a full backup. During a normal backup, all selected files on the disk are archived to the backup medium. These files are marked as having been archived by clearing the archive bit.
Copy Backup
A copy backup copies all selected files. It does not mark the files as having been archived.
Differential Backup
A differential backup backs up all the files and folders that have been created or modified since either the last normal backup or the last incremental backup (see below). The differential backup does not mark the files as having been archived. Copies are made from the same starting point until the next incremental or full backup is performed. Making differential backups is important because only the last full and differential backups are needed to restore all the data.
Incremental Backup
An incremental backup procedure backs up all the files and folders that have been created or modified since either the last normal or incremental backup. It marks the files as having been archived by clearing the archive bit. This has the effect of advancing the starting point of differential backups without having to re-archive the entire contents of the drive. If you must perform a system restore, restore the last full backup first, then restore each incremental backup in order, and finally, restore the differential backups made since the last incremental backup.
Daily Backup
Daily backups only back up the files that are modified on the day of the backup. Daily backups do not modify the archive bit.
To access the daily backup utility on a Windows XP Professional system, use the following path:
Start > All Programs > Accessories > System Tools > Backup
To access the daily backup utility in Windows Vista, use the following path:
Start > All Programs > Accessories > System Tools > Backup Status and Configuration
Backup Media
Many types of backup media are available for computers:
Tape drives are devices that are used for data backup on a network server drive. Tapes drives are an inexpensive way to store a lot of data.
The Digital Audio Tape (DAT) tape standard uses 4 mm digital audiotapes to store data in the Digital Data Storage (DSS) format.
Digital Linear Tape (DLT) technology offers high-capacity and relatively high-speed tape backup capabilities.
USB flash memory can hold hundreds of times the data that a floppy disk can hold. USB flash memory devices are available in many capacities and offer better transfer rates than tape devices.
Optical media, such as CDs, DVDs, and Blu-ray Discs, are plastic discs used to store data. Many formats and capacities of optical media are available. A DVD holds much more data than a CD, and a Blu-ray Disc holds much more data than a DVD.
External Hard Disk Drives (HDDs) are hard drives that are connected to your computer using a USB, FireWire, or external Serial ATA (eSATA) connection. External HDDs can hold very large amounts of data and can transfer data very quickly.
Most operating systems contain utilities to assist in the troubleshooting process. These utilities help technicians determine why the computer crashes or does not boot properly. The utilities also help identify the problem and how to resolve it.
Follow the steps outlined in this section to accurately identify, repair, and document the problem. The troubleshooting process is shown in Figure 1.
After completing this section, you will meet these objectives:
Review the troubleshooting process.
Identify common problems and solutions.
Operating system problems can result from a combination of hardware, application, and configuration issues. Computer technicians must be able to analyze the problem and determine the cause of the error to repair the operating system. This process is called troubleshooting.
The first step in the troubleshooting process is to identify the problem. Figure 1 lists open-ended and closed-ended questions to ask the customer.
After you have talked to the customer, you should establish a theory of probable causes. Figure 2 lists some common causes of operating system problems.
After a theory of probable causes has been established, try to determine an exact cause of the problem. Figure 3 lists common steps to determine the cause of operating system problems.
If you were unable to determine the cause of the problem, use Step 4 in the troubleshooting process to research the problem more thoroughly. Figure 4 shows sources of information to gather additional information to resolve an issue.
At this point, you will be able to verify the solution and the full system functionality. Figure 5 shows how to validate your implementation of the solution.
After you have solved the operating system problem, document your findings. Figure 6 is a list of the tasks required to complete this step.
Operating system problems can be attributed to hardware, application, or configuration issues, or to some combination of the three. You will resolve some types of operating system problems more often than others. Figure 1 is a chart of common operating system problems and solutions.
This chapter introduced computer operating systems. As a technician, you should be skilled at installing, configuring, and troubleshooting an operating system. The following concepts from this chapter are important to remember:
Several different operating systems are available, and you must consider the customer's needs and environment when choosing an operating system.
The main steps in setting up a customer's computer include preparing the hard drive, installing an operating system, creating user accounts, and configuring installation options.
A GUI shows icons of all files, folders, and applications on the computer. A pointing device, such as a mouse, is used to navigate in a GUI desktop.
You should establish a backup strategy that allows for the recovery of data. Normal, copy, differential, incremental, and daily backups are all optional backup tools available in Windows operating systems.
Preventive maintenance techniques help to ensure optimal operation of the operating system.
Some of the tools available for troubleshooting an operating system problem include Windows Advanced Options menu, event logs, device manager, and system files.
Chapter 6
Do you know when the first laptops were developed? Who do you think used the early laptops?
One of the original laptops was the GRiD Compass 1101. It was used by astronauts on space missions in the early 1980s. It weighed 11 lb (5 kg) and cost US $8,000 - $10,000! Laptops today often weigh less than one-half the weight and cost less than one-third the price of the GRiD. The compact design, convenience, and evolving technology of laptops have made them as popular as desktops.
Laptops, Personal Digital Assistants (PDAs), and smartphones are becoming more popular as their prices decrease and technology continues to progress. As a computer technician, you need to have knowledge of portable devices of all kinds. This chapter focuses on the differences between laptops and desktops and describes the features of PDAs and smartphones.
After completing this chapter, you will meet these objectives:
Describe laptops and other portable devices.
Identify and describe the components of a laptop.
Compare and contrast desktop and laptop components.
Explain how to configure laptops.
Compare the different mobile phone standards.
Identify common preventive maintenance techniques for laptops and portable devices.
Describe how to troubleshoot laptops and portable devices.
Note: Notebooks, laptops, and tablets are types of portable computers. For clarity and consistency in this course, all portable computers are called laptops.
Laptops
Early laptops were heavy and expensive. Today, laptops are very popular because advances in technology have resulted in laptops that cost less, weigh less, and have improved capabilities. Many laptops can be configured with an additional video port, a FireWire port, an infrared port, or an integrated camera.
PDAs and Smartphones
PDAs and smartphones are examples of portable, handheld devices that are becoming more popular. PDAs offer features such as games, web surfing, e-mail, instant messaging, and many other features offered by PCs. Smartphones are cell phones with many built-in PDA capabilities. PDAs and smartphones can run some of the same software as laptops.
After completing this section, you will meet these objectives:
Identify some common uses of laptops.
Identify some common uses of PDAs and smartphones.
The most significant feature of a laptop is its compact size. The design of the laptop places the keyboard, screen, and internal components into a small, portable case.
Another popular feature of the laptop is its portability. A rechargeable battery allows the laptop to function when it is disconnected from an AC power source.
The first laptops were used primarily by business people who needed to access and enter data when they were away from the office. The use of laptops was limited due to expense, weight, and limited capabilities compared to less expensive desktops.
Today, laptops have lower prices and increased capabilities. A laptop is now a real alternative to a desktop computer.
Here are some common uses for the laptop:
Taking notes in school or researching papers
Presenting information in business meetings
Accessing data away from home or the office
Playing games while traveling
Watching movies while traveling
Accessing the Internet in a public place
Sending and receiving e-mail in a public place
Can you think of other uses for laptops?
The concept of the PDA has existed since the 1970s. The earliest models were computerized personal organizers designed to have a touch screen or a keyboard. Today, some models have both a touch screen and a keyboard and use an operating system that is similar to operating systems used on desktop computers.
The PDA is an electronic personal organizer with tools to help organize information:
Address book
Calculator
Alarm clock
Internet access
Global positioning
The smartphone is a mobile phone with PDA capabilities. Smartphones combine cell phone and computer functions in a single, handheld device. The technology of the PDA and the technology of the smartphone continue to merge.
Smartphones may include these additional options:
Built-in camera
Document access
Abbreviated note-taking
Television
Smartphone connectivity and PDA connectivity include Bluetooth and regular USB cable connections.
Can you think of other uses for the PDA and the smartphone?
What are some common laptop features?
They are small and portable.
They have an integrated display screen in the lid.
They have an integrated keyboard in the base.
They run on AC power or a rechargeable battery.
They support hot-swappable drives and peripherals.
Most laptops can use docking stations and port replicators to connect peripherals.
In this section, you will look closely at the components of a laptop. You will also examine a docking station. Remember, laptops and docking stations come in many models. Components might be located in different places on different models.
After completing this section, you will meet these objectives:
Describe the components found on the outside of the laptop.
Describe the components found on the inside of the laptop.
Describe the components found on the laptop docking station.
Laptop and desktop computers use the same types of ports so that peripherals can be interchangeable. These ports are specifically designed for connecting peripherals, providing network connectivity, and providing audio access.
Ports, connections, and drives are located on the front, back, and sides of the laptop due to the compact design. Laptops contain PC Card or ExpressCard slots to add functionality such as more memory, a modem, or a network connection.
Laptops require a port for external power. Laptops can operate using either a battery or an AC power adapter. This port can be used to power the computer or to charge the battery.
Status indicators, ports, slots, connectors, bays, jacks, vents, and a keyhole are on the exterior of the laptop. Click the highlighted areas in Figures 1 to 7 to discover additional information about each of these components.
Figure 1 shows three LEDs on the top of the laptop. Click the three highlighted areas for more information about what the LEDs indicate:
Bluetooth
Battery
Standby
NOTE: LED displays vary among laptops. Technicians should consult the laptop manual for a list of specific status displays.
Figure 2 shows three components on the back of the laptop. Click the three highlighted areas for more information about the components:
Parallel port
AC power connector
Battery bay
A laptop operates using either a battery or an AC power adapter. Laptop batteries are manufactured in various shapes and sizes. They use different types of chemicals and metals to store power. Refer to Figure 3 to compare rechargeable batteries.
The left side of the laptop shown in Figure 4 has ten components. Click the ten highlighted areas for more information about the components:
Security keyhole
USB
S-video connector
Modem RJ-11
Ethernet RJ-45
Network LEDs
Stereo headphone jack
Microphone jack
Ventilation
PC combo expansion slot
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The front of the laptop shown in Figure 5 has the components listed here. Click the four highlighted areas for more information about the components:
Ventilation
Speakers
Infrared port
Laptop latch
The right side of the laptop shown in Figure 6 contains four components. Click the four highlighted areas for more information about the components:
VGA port
Drive bay status indicator
Optical drive activity indicator
Optical drive
The bottom of the laptop shown in Figure 7 has the components listed here. Click the five highlighted areas for more information about the components:
Docking station connector
Battery latches (two areas)
RAM access panel
Hard drive access panel
Laptops use input devices to add functionality to the laptop. Installing input devices might require downloading drivers from the manufacturer's website. There are a variety of input devices:
Stylus or digitizer
Tablet
Barcode reader
Scanner
Light pen
Web camera
PC game device
Some input devices might need to be configured or optimized for speed, sensitivity, scrolling, or the number of taps needed. To gain access to these configuration utilities for input devices, use the following path:
Start > Control Panel > Mouse
Not all devices can be configured through the Control Panel. When you install the software for some devices, programs might be installed in the All Programs section of the Start menu. These programs are used to configure more advanced settings.
Some input devices are built into the laptop. Typically, the laptop is closed when not in use. By opening the lid of the laptop, you can access a variety of input devices, LEDs, and a display screen. Click the five highlighted areas in Figure 1 for more information about the input devices:
Keyboard
Input devices
Fingerprint reader
Volume controls
Power button
Refer to Figure 1. Do you know which of these devices perform the following functions?
Move the pointer.
Turn up the volume.
Log on to the laptop.
Type a document.
Turn on the laptop.
Switch to the external monitor.
At the bottom of the screen is a row of LEDs that shows the status of specific functions. Click the eight highlighted areas in Figure 2 for more information on these LEDs:
Wireless
Bluetooth
Num Lock
Caps Lock
Hard drive activity
Power on
Battery status
Hibernate/Standby
NOTE: Indicators vary by laptop.
A laptop monitor is a built-in LCD. It is similar to a desktop LCD monitor, except that the resolution, brightness, and contrast settings can be adjusted using software or button controls. The laptop monitor cannot be adjusted for height and distance because it is integrated into the lid of the case. A desktop monitor can be added to a laptop. An Fn key on the laptop keyboard toggles between the laptop display and the desktop monitor, as shown in Figure 3.
The purpose of the Fn key is to activate a second function on a dual-purpose key. The feature that is accessed by pressing and holding the Fn key is printed on another key in a smaller font or different color. There are several functions that can be accessed:
Volume setting
Display brightness
Sleep states
Wireless functionality
Check battery status
The Fn key must not be confused with function keys F1 through F12. These keys are typically located in a horizontal row across the top of the keyboard. Their function depends on the operating system and application that is running when they are pressed. Each key can be made to perform up to seven separate operations. The key can be pressed alone or with one or more combinations of the Shift, Control, and Alt keys.
On many laptops, a small pin on the laptop cover contacts a switch when the case is closed, called an LCD cutoff switch. The LCD cutoff switch tells the CPU to conserve power by extinguishing the backlight and turning off the LCD. If this switch breaks or is dirty, the LCD remains dark while the laptop is open. Carefully clean this switch to restore normal operation.
A base station is a device that attaches to AC power and to desktop peripherals. When you plug the laptop into the base station, you have convenient access to power and the attached peripherals.
There are two types of base stations: docking stations and port replicators. Docking stations and port replicators are used for the same purpose. Port replicators are usually smaller than docking stations and do not have speakers or PCI slots. Docking stations and port replicators use a variety of connection types:
Manufacturer- and model-specific
USB or FireWire
PC-Card or ExpressCard
Figures 1 to 3 illustrate a docking station.
Click the three highlighted areas in Figure 1 for more information about components on the top of the docking station:
Power button
Eject button
Docking connector
Some docking stations include the following drive bays and ports to provide additional functionality:
Parallel
USB
Ethernet
Video
Audio
The back of the docking station contains ports and connectors used to attach to desktop peripherals such as a mouse, a monitor, or a printer. A vent is also necessary to expel hot air from the docking station. Click the 15 highlighted areas in Figure 2 for more information about the components located on the back of the docking station:
Exhaust vent
AC power connector
PC Card or ExpressCard slot
VGA port
DVI port
Line In connector
Headphone connector
USB port
Mouse port
Keyboard port
External-diskette-drive connector
Parallel port
Serial port
Modem port
Ethernet port
Secure the laptop to the docking station with a key lock. Click the highlighted area in Figure 3 for more information about the key lock located on the right side of the docking station.
Most of the functions that a desktop can perform can also be performed by a laptop. However, these two kinds of computers are built very differently and the parts are not interchangeable. As an example, a plane and a helicopter can each travel to the same destination, but they cannot be repaired with the same spare parts. This is also true for laptops and desktops. Few components can be shared between desktops and laptops.
Desktop components tend to be standardized. They usually meet universal form factors. Desktops made by different manufacturers can often use the same components. A DVD/CD-RW drive is an example of a desktop component that has a standard form factor.
Laptop components are much more specialized than desktop components. This difference is because laptop manufacturers focus on refining components to make them more efficient and compact. As a result, manufacturers design laptop components to follow their own specific form factors. Laptop components are proprietary. You might not be able to use components made by one laptop manufacturer to repair a laptop made by another manufacturer.
NOTE: Technicians might have to obtain certification for each laptop manufacturer that they support.
After completing this section, you will meet these objectives:
Compare and contrast desktop and laptop motherboards.
Compare and contrast desktop and laptop processors.
Compare and contrast desktop and laptop power management.
Compare and contrast desktop and laptop expansion capabilities.
Desktop motherboards have standard form factors. The standard size and shape allow motherboards from different manufacturers to be interchangeable.
Laptop motherboards vary by manufacturer and are proprietary. When you repair a laptop, it is strongly recommended that you obtain a replacement motherboard from the manufacturer of the laptop. Figure 1 shows a desktop motherboard and a laptop motherboard.
Laptop motherboards and desktop motherboards are designed differently. Components designed for a laptop generally cannot be used in a desktop. Figure 2 shows a few examples of the design differences.
Laptops, some printers, and routers have space restrictions; therefore, they use Small Outline Dual In-line Memory Modules (SODIMMs), as shown in Figure 3.
The CPU is the brain of the computer. The CPU interprets and processes instructions that are used to manipulate data.
Laptop processors are designed to use less power and create less heat than desktop processors. As a result, laptop processors do not require cooling devices that are as large as those found in desktops. Laptop processors also use CPU throttling to modify the clock speed as needed to reduce power consumption and heat. This results in a slight decrease in performance. It also increases the lifespan of some components. These specially designed processors allow laptops to operate for a longer period of time when using a battery power source. Figure 1 shows laptop processor specifications.
NOTE: Technicians should refer to the laptop manual for processors that can be used as replacement processors and for processor replacement instructions.
Power management controls the flow of electricity to the components of a computer.
Desktops are usually set up in a location where they remain plugged into a power source. Desktop power management distributes electricity from the source to the components of the desktop. There is also a small battery in the desktop that provides electricity to maintain the internal clock and BIOS settings when the desktop is powered off.
Laptops are small and portable. This portability feature is achieved by combining the small size and weight of a laptop with the ability to operate from a battery. Unlike a desktop computer power supply, laptops can accept only DC power. AC adapters convert unregulated AC power to the regulated DC power required to run the laptop and charge the laptop battery.
When the laptop is plugged in, laptop power management sends electricity from the AC power source to the laptop components. The laptop power management also recharges the battery. When the laptop is unplugged, laptop power management takes electricity from the battery and sends it to the laptop components.
There are two methods of power management:
Advanced Power Management (APM)
Advanced Configuration and Power Interface (ACPI)
APM is an earlier version of power management. With APM, the BIOS was used to control the settings for power management.
ACPI has replaced APM. ACPI offers additional power management features. With ACPI, the operating system controls power management.
Expansion capabilities add functionality to a computer. Many expansion devices can be used with both laptops and desktops:
External drives
Modems
Network cards
Wireless adapters
Printers
Other peripherals
Expansion devices are attached to laptops and desktops differently. A desktop attaches these devices with serial, parallel, USB, and FireWire ports. A laptop attaches these devices with the same ports and PC Cards.
The standardized use of USB and FireWire ports makes it possible to connect many types of external components to laptops, docking stations, port replicators, and desktops. The USB and FireWire standards make it possible to connect and remove external components without the need to power off the system. USB and FireWire ports are used to connect a range of external components:
Printers
Scanners
Floppy disk drives
Mice
Cameras
Keyboards
Hard drives
Flash drives
Optical drives
MP3 players
Laptops and desktops have similar expansion capabilities. It is the difference in form factor between the computers that determines which type of expansion device is used. Desktops have internal bays that support 5.25" and 3.5" drives. Additionally, there is space to install other permanent expansion drives. Laptops have limited space; therefore, the expansion bays on laptops are designed to allow different types of drives to fit into the same bay. Drives are hot-swappable and are inserted or removed as needed. Figure 1 shows a comparison of desktop and laptop expansion components.
Expansion devices used for data storage use three types of storage methods:
Magnetic
Flash
Optical
Traditional hard drives are magnetic. Magnetic hard drives have drive motors designed to spin magnetic platters and the drive heads.
A flash drive uses a special type of memory that requires no power to maintain the data. Flash memory chips manage all storage on a Solid State Drive (SSD), which results in faster access to data, higher reliability, and reduced power usage. SSDs do not have moving parts. Because there are no drive motors and moving parts, the SSD uses far less energy than the magnetic hard drive.
The optical drive is a storage device that uses lasers to read data on the optical medium. Optical drives have moving parts like hard drives. They have drive motors designed to spin a platter and move a drive head. There are three types of optical drives:
CD
DVD
Blu-ray Disc (BD)
CD, DVD, and BD media can be pre-recorded (read-only), recordable (write once), or re-recordable (read and write multiple times). CDs have a data storage capacity of approximately 700 MB. DVDs have a data storage capacity of approximately 8.5 GB on one side of the disc. BDs have a storage capacity of 25 GB on a single-layer disc, and 50 GB on a dual-layer disc.
Laptops use the PC Card slot to add functionality. The PC Card slot uses an open standard interface to connect to peripheral devices using the CardBus standard. Here are some examples of devices that connect using PC Cards:
Memory
Modems
Hard drives
Network cards
PC Cards follow the PCMCIA standard. They come in three types: Type I, Type II, and Type III. Each type of PC Card is different in size and can attach to different devices. A newer type of PC Card is called the PC ExpressCard. Figure 2 shows a comparison of PC Cards and PC ExpressCards. The PC ExpressCard comes in 34mm and 54mm widths. Figure 3 shows an example of a PC Card and PC ExpressCards.
Suppose that you need to purchase a wireless NIC for a laptop. Which type of PC Card would you select?
To allow applications and processes to run smoothly, it might be necessary to configure and allocate system resources, install additional components and plug-ins, or change environmental settings to match software requirements. Adding external components is usually accomplished through the use of Plug and Play, but occasionally driver installation and additional configuration might be required. Proper configuration of the power settings helps you get the maximum performance from a laptop, such as increasing the length of time the laptop can be used on battery power.
With laptops, it might be necessary to exchange components as needed to accomplish different tasks and respond to changing situations and needs. A laptop can be customized for specific purposes by adding external components. For example, a second hard drive can be installed in a laptop to provide additional storage capacity. Components need to be carefully inserted or connected to bays, connectors, and proprietary expansion areas to avoid damage to the equipment. It is important to follow safe removal procedures when disconnecting hot-swappable and non-hot-swappable devices.
After completing this section, you will meet these objectives:
Describe how to configure power settings.
Describe the safe installation and removal of laptop components.
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One of the most popular features of a laptop is the ability to operate using batteries. This feature allows laptops to operate in locations where AC power is not available or is inconvenient. Advances in power management and battery technology are increasing the time that laptop users can remain disconnected from AC power. Current batteries can last anywhere between 2 to 10 hours without recharging. Managing the power by configuring the power settings on a laptop is important to ensure that the battery charge is used efficiently.
The ACPI standards create a bridge between the hardware and OS and allow technicians to create power management schemes to get the best performance from the computer. The ACPI standards can be applicable to most computers, but they are particularly important when managing power in laptops. Click the power states in Figure 1 to view more information about each power state.
NOTE: When working in Windows XP or Windows Vista, the ACPI power management mode must be enabled in BIOS to allow the OS to configure all of the power management states.
Technicians frequently are required to configure power settings by changing the settings found in BIOS. Configuring power settings in BIOS affects the following conditions:
System states
Battery and AC modes
Thermal management
CPU PCI bus power management
Wake-On-LAN (WOL)
NOTE: WOL might require a cable connection inside the computer from the network adapter to the motherboard.
Figure 2 shows an example of power settings in BIOS.
NOTE: There is no standard name for each power management state. Manufacturers might use different names for the same state.
Here are the steps to check the ACPI settings in BIOS:
Enter BIOS setup by pressing the appropriate key or key combination while the computer is booting. Typically this is the Delete key or the F2 key, but there are several other options.
Locate and enter the Power Management settings menu item.
Use the appropriate keys to enable ACPI mode.
Save and exit BIOS setup.
NOTE: These steps are common to most laptops and should be used only as a guideline. Be sure to check your laptop manual for specific configuration settings.
The Power Options feature in Windows XP or Windows Vista allows you to reduce the power consumption of a number of devices or of the entire system. Use Power Options to control the power management features of the following:
Hard drive
Display
Shut Down, Hibernate, and Suspend modes (Windows XP)
Shut Down, Hibernate, and Sleep modes (Windows Vista)
Low-battery warnings
Configuring Power Settings in Windows XP and Windows Vista
You can adjust power management by using Power Options in the Control Panel. The Power Options displays only the options that can be controlled.
NOTE: Power Options automatically detects devices that might be unique to your computer; therefore, the Power Options windows might vary by the hardware that is detected.
To configure your power settings, click:
Start > Control Panel > Power Options
Managing Power Usage
Power Schemes and Power Plans are a collection of hardware and system settings that manage the power usage of the computer. These power settings can help you save energy, maximize system performance, or achieve a balance between the two. Both the hard drive and the display consume large amounts of power. They can be configured under the Power Schemes tab in Windows XP and the Change Plan settings in Windows Vista.
When you open Power Options, you will notice that Windows XP has preset power schemes and Windows Vista has preset power plans. These are the default settings and were created when the operating system was installed. You can use the default setting, or create customized schemes or plans that are based on specific work requirements. Customized sleep timers are shown in Figure 3 for Windows XP Power Scheme and in Figure 4 for Windows Vista Power Plan.
To configure sleep timers in Windows XP, click:
Start > Control Panel > Power Options > select the time you want.
To configure sleep timers in Windows Vista, click:
Start > Control Panel > Power Options > click the link Change when the computer sleeps > select the time you want.
Power Management for the Hard Drive and the Display
One of the biggest power consumers on a laptop is the hard drive. In our example, the hard drive is not accessed often. The “Turn off hard disks” time is set for 1 hour when the laptop is plugged in, and 3 minutes when the laptop is “Running on batteries”. You can also set the LCD to turn off after a specified period of time.
You decide that Windows XP default settings for the Standby and Hibernate modes are acceptable and no changes are made. In Windows Vista these settings are Sleep, Hybrid Sleep, and Hibernate. Power Schemes and Power Plans can be saved with a customized name. Saving the new setting with a custom name allows the user to easily switch back to the default settings. In Figure 5 and Figure 6, the new settings are saved with the name Research.
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Setting the Laptop Power Options
If you do not want to completely shut down the laptop, you have two options in Windows XP: Standby and Hibernate.
Standby – Documents and applications are saved in RAM, allowing the computer to power on quickly.
Hibernate – Documents and applications are saved to a temporary file on the hard drive, and takes a little longer than Standby to power on.
Figure 7 shows Hibernate enabled in the Power Options properties.
If you do not want to completely shut down the laptop, you have three options in Windows Vista: Sleep, Hybrid Sleep and Hibernate.
Sleep – Documents and applications are saved in RAM, allowing the computer to power on quickly.
Hybrid Sleep – Documents and applications are saved in RAM and data is written to the hard disk, and takes a little longer than Sleep to power on.
Hibernate – Documents and applications are saved to a temporary file on the hard drive, and takes a little longer than Hybrid Sleep to power on.
Adjusting Low Battery Warnings
In Windows XP, you can set the low battery warnings. There are two levels: Low Battery Alarm and Critical Battery Alarm. The Low Battery Alarm warns you that the battery is low. The Critical Battery Alarm initiates a forced standby, hibernate, or shut down mode, as shown in Figure 8. Standby is called Sleep in Windows Vista.
Some components of a laptop might need to be replaced. Remember always to make sure that you have the correct replacement component and tools as recommended by the manufacturer. Some components are hot-swappable, which means that they can be removed and replaced while the computer is on. These are some components that might need to be replaced:
AC adapter
Battery
Optical drive
Hard drive
Memory
PC expansion cards
Figure 1 shows an example of a laptop.
NOTE: Each laptop manufacturer uses unique hardware installation and removal procedures. Check the laptop manual for specific installation information and follow safety installation and ESD precautions.
CAUTION: Always disconnect power and remove the battery before installing or removing laptop components that are not hot-swappable.
AC adapters must be compatible with the manufacturer and model of laptop that you have. AC adapters are either auto-switching or fixed input. Auto-switching AC adapters can switch between 110V and 220V, while a fixed input AC adapter only operates under a specific voltage. Auto switching allows the power supply to be used in different countries.
Battery Replacement Steps [Figure 2]
Remove the battery from the battery bay:
Move the battery lock to the unlocked position.
Hold the release lever in the unlock position and remove the battery.
Install the battery into the battery bay:
Insert the battery.
Make sure that both battery levers are locked.
Optical Drive Replacement Steps [Figure 3]
Remove the DVD/CD-RW drive:
Press the button to open the drive and remove any media in the drive. Close the tray.
Slide the latch to release the lever that secures the drive.
Pull on the lever to expose the drive. Remove the drive.
Install the DVD/CD-RW drive:
Insert the drive securely.
Push the lever inward.
Hard Drive Replacement Steps [Figure 4]
Remove the hard drive:
On the bottom of the laptop, remove the screw that holds the hard drive in place.
Slide the assembly outward. Remove the hard drive assembly.
Remove the hard drive faceplate from the hard drive.
Install the hard drive:
Attach the hard drive faceplate to the hard drive.
Slide the hard drive into the hard drive bay.
On the bottom of the laptop, install the screw that holds the hard drive in place.
Expansion Memory Replacement Steps [Figure 5]
Laptop expansion memory is also called SODIMM. Remove the existing SODIMM if there are no available slots for the new SODIMM:
Remove screw to expose the SODIMM.
Press outward on the clips that hold the sides of the SODIMM.
Lift up to loosen the SODIMM from the slot and remove the SODIMM.
Install the SODIMM:
Align the notch at a 45-degree angle.
Gently press down until clips lock.
Replace cover and install screw.
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PC Expansion Card Replacement Steps [Figure 6]
All PC expansion cards, including ExpressCards, are inserted and removed using similar steps.
To remove the PC expansion card, press the top eject button to release it.
NOTE: There are two buttons. The bottom blue button ejects the Type II PC card.
Install the PC expansion card:
Press the blue button inward.
Insert the PC expansion card into the express slot.
CAUTION: On some laptops, the PC Card, optical drive, and USB devices are hot-swappable. However, the internal hard drive, RAM, and battery are NOT hot-swappable.
Hot-Swappable Device Removal Steps
Left-click the Safely Remove Hardware icon in the Windows system tray to ensure that the device is not in use.
Left-click the device that you want to remove. A message pops up to tell you that it is safe to remove the device.
Remove the hot-swappable device from the laptop.
Optional Activity
Laptops use several different communication methods:
Ethernet
Wireless Ethernet
Modem
Bluetooth
Infrared
Cellular WAN
Ethernet Installation and Configuration Steps
Plug the Ethernet cable into the NIC port.
Configure IP address information.
Windows XP:
Start > Control Panel > Network Connections > right click Local Area Connection > Properties > TCP/IP > Properties > configure IP setting > OK > OK.
Windows Vista:
Start > Control Panel > Network and Sharing Center > Manage network connections > right-click the connection that you want to set up > Properties > TCP/IPv4 > Properties > configure IP setting > OK > OK.
Wireless Ethernet Installation and Configuration
Wireless Ethernet NICs can be built into the laptop or attached to the laptop through one of the various laptop expansion ports. Wireless NIC IP address information is configured in the same way as wired NICs.
Modem Installation and Configuration Steps [Figure 1]
Make sure the modem is installed and turned on if an external modem is attached.
Attach a phone cable from the wall outlet to the appropriate RJ-11 modem port.
Use the Install New Modem Wizard to add the modem.
Windows XP:
Start > Control Panel > Phone and Modem Options > specify the dialing information for your location > OK > Add Hardware Wizard starts > Modems > Add > Next > Add Hardware Wizard installs the device > Finish.
Windows Vista:
Start > Control Panel > Phone and Modem Options > specify the dialing information for your location > OK > Add Hardware Wizard starts > Modems > Add > if prompted for permission click Continue > Next > Add Hardware Wizard installs the device > Finish.
You can use the Phone and Modem Options tabs to configure settings:
Dialing Rules – List, add, edit, and delete dialing locations.
Modems – Add, remove a device, or view the properties of a device.
Advanced – List, add, remove, and configure telephony providers installed on the computer.
NOTE: To configure an installed modem, open Phone and Modem Options in the Control Panel. On the Modems tab, click the modem you want to configure, and then click Properties.
Bluetooth Installation and Configuration Steps [Figure 2]
Windows activates Bluetooth connections by default. If the connection is not active, look for a switch on the front face or on the side of the laptop to enable the connection. Figure 3 shows the LED status for Bluetooth.
Make sure Bluetooth is enabled in the BIOS before installing and configuring the device.
Turn on the device and make it discoverable to Windows. Check the device documentation to learn how to make your device discoverable.
Use the Bluetooth Wizard to search and discover any Bluetooth devices that are in Discoverable mode.
Windows XP:
Start > Control Panel > Bluetooth Devices > Device > Add > Add Bluetooth Device Wizard starts > My device is set up and ready to be found > Next > select the discovered device > Next > if prompted, enter a passkey > Next > Finish.
Windows Vista:
Start > Control Panel > Network and Internet > Set up a Bluetooth enabled device > Device > Add > if prompted, click Continue > Add Bluetooth Device Wizard starts > My device is set up and ready to be found > Next > select the discovered device > Next > if prompted, enter a passkey > Finish.
You can use the Bluetooth Devices tabs to configure Bluetooth settings:
Device – Adds, removes a device, or views the properties of a device.
Options – Controls how devices discover and connect to your computer.
COM Ports – Sets up new incoming and outgoing serial ports.
Hardware – Lists Bluetooth devices that are installed on your computer.
Infrared Installation and Configuration Steps [Figure 4]
Make sure infrared is enabled in the BIOS before installing and configuring the device.
Turn on the device to make it discoverable to Windows.
Align your devices so that the infrared transceivers are within one meter of each other, and the transceivers are pointing at each other.
When the devices are correctly aligned, an icon appears on the taskbar with a pop-up message.
Click the pop-up message to display the Infrared dialog box.
In both Windows XP and Windows Vista the Infrared dialog box can be accessed in the Control Panel.
Laptops without an internal infrared device can connect a serial infrared transceiver to a serial port or a USB port. Figure 5 shows an internal infrared port transceiver.
You can use the Infrared dialog box tabs to configure infrared settings:
Infrared – Control how you are notified about an infrared connection, and control how files are transferred.
Image Transfer – Control how images are transferred from a digital camera.
Hardware – Lists infrared devices that are installed on your computer.
Cellular WAN Installation and Configuration Steps
Laptops with integrated cellular WAN capabilities require no software installation and no additional antenna or accessories. When you turn on the laptop, the integrated WAN capabilities are ready to be used. If the connection is not active, look for a switch on the front face or on the side of the laptop to enable the connection.
Make sure cellular WAN is enabled in the BIOS before installing and configuring the device.
Install the manufacturer’s broadband card utility software.
Use the utility software to manage the network connection.
The cellular WAN utility software can be located in the taskbar or in Start > Programs.
standards applying to cell phone technology. Without standards, it was difficult and expensive to make calls to people that were on another network. Today, cell phone providers use industry standards, which makes it easier to use cell phones to make calls.
When the industry started, most cell phone standards were analog. Today, cell phone standards are mostly digital.
NOTE: Cell phone standards have not been adopted uniformly around the world. Some cell phones are capable of using multiple standards, whereas others can use only one standard. As a result, some cell phones can operate in many countries, and other cell phones can only be used locally.
The first generation (1G) of cell phones began service in the 1980s. First-generation phones primarily used analog standards, including Advanced Mobile Phone System (AMPS) and Nordic Mobile Telephone (NMT). In an analog system, the voice information is sent by varying the radio signals used by the phone in the same pattern as the speakers’ voices. Unfortunately, this means that interference and noise, which also vary the signal, cannot easily be separated from the voice in the signal. This factor limits the usefulness of analog systems.
Digital signals convert the speakers’ voices into a series of ones and zeros. This technology degrades the signal a little, because ones and zeros are not a faithful representation of your voice. However, the digital signal is robust. It can be fixed using error correction routines if there is interference. Also, digital signals can be compressed, making the systems much more efficient than analog.
In the 1990s, the second generation (2G) of cell phones was marked by a switch from analog to digital standards. Second-generation cell standards included Global System for Mobile (GSM), Integrated Digital Enhanced Network (iDEN), and Code Division Multiple Access (CDMA).
Third-generation standards enable cell phones to go beyond simple voice and data communications. It is now common for cell phones to send and receive text, photos, and video. It is also common for 3G cell phones to access the Internet and to use the Global Positioning System (GPS).
NOTE: As 3G cell phone standards were being developed, extensions to the existing 2G standards were added. These transitional standards are known as 2.5G standards.
Fourth-generation (4G) standards have been championed by many users in response to the availability of increased data rates. Higher data rates will allow users to download files, such as video and music, faster than what was available with standards of previous generations.
Click the five generation tabs in Figure 1 to view more information about the different cell phone standards.
New technologies that add multimedia and networking functionality can be bundled with cell phone standards. Figure 2 lists common technologies that can be added to the cell phone bundle of services. Most cell phone providers charge extra for adding these features.
Because laptops are mobile, they are used in different types of environments. Some environments can be hazardous to a laptop. Even eating or drinking around a laptop creates a potentially hazardous condition.
Consider what would happen if a drink were spilled onto the keyboard of a laptop. Many components are placed in a very small area directly beneath the keyboard. Spilling liquid or dropping debris onto the keyboard can result in severe internal damage.
It is important to keep a laptop clean and to ensure that it is being used in the most optimal environment possible. This section covers preventive maintenance techniques for the laptop.
After completing this section, you will meet these objectives:
Identify appropriate cleaning procedures.
Identify optimal operating environments.
Proper routine cleaning is the easiest, least expensive way to protect and to extend the life of a laptop. It is very important to use the right products and procedures when cleaning a laptop. Always read all warning labels on the cleaning products. The components are very sensitive and should be handled with care. Consult the laptop manual for additional information and cleaning suggestions.
Laptop Keyboard Cleaning Procedures
Turn off the laptop.
Disconnect all of the attached devices.
Disconnect the laptop from the electrical outlet.
Remove all of the installed batteries.
Wipe the laptop and the keyboard with a soft, lint-free cloth that is lightly moistened with water or computer-screen cleaner.
Ventilation Cleaning Procedures
Turn off the laptop.
Disconnect all of the attached devices.
Disconnect the laptop from the electrical outlet.
Remove all of the installed batteries.
Use compressed air or a non-electrostatic vacuum to clean out the dust from the vents and from the fan behind the vent.
Use tweezers to remove any debris.
LCD Cleaning Procedures
Turn off the laptop.
Disconnect all of the attached devices.
Disconnect the laptop from the electrical outlet.
Remove all of the installed batteries.
Wipe the display with a soft, lint-free cloth that is lightly moistened with a mild cleaning solution.
CAUTION: Do not spray cleaning solution directly onto the LCD display. Use products specifically designed for cleaning LCD displays.
Touch Pad Cleaning Procedures
Turn off the laptop.
Disconnect all of the attached devices.
Disconnect the laptop from the electrical outlet.
Remove all of the installed batteries.
Wipe the surface of the touch pad gently with a soft, lint-free cloth that is moistened with an approved cleaner. Never use a wet cloth.
The small screen of a PDA or smartphone requires special care. The user operates these devices by touching the screen with a stylus. If dirt is present, the PDA might not accurately detect the stylus position or movement. The dirt can also scratch the screen. Clean the screen with a small amount of non-abrasive cleaning solution on a soft cloth. To protect the screen surface from a stylus, use self-adhesive screen covers.
CAUTION: Use a soft, lint-free cloth with an approved cleaning solution to avoid damaging laptop surfaces. Apply the cleaning solution to the lint-free cloth, not directly to the laptop.
Floppy Drive Cleaning Procedures
Use a commercially-available cleaning kit to clean a floppy drive. Floppy drive cleaning kits include pre-treated floppy discs that remove contaminants from the floppy drive heads that have accumulated through normal operation.
Remove all of the media from the floppy drive.
Insert the cleaning disc and let it spin for the suggested amount of time.
Optical Drive Cleaning Procedures
Dirt, dust, and other contaminants can collect in the optical drives. Contaminated drives can cause malfunctions, missing data, error messages, and lost productivity.
Use a commercially-available CD or DVD drive cleaning disc. Many floppy disc cleaning kits include an optical disc cleaner. Like the floppy disc cleaner, optical disc cleaner kits contain a cleaning solution and a non-abrasive disc that is inserted into the optical drive.
Remove all of the media from the optical drive.
Insert the cleaning disc and let it spin for the suggested amount of time to clean all contact areas.
Cleaning a CD or DVD Disc
Inspect the disc for scratches. Replace discs that contain deep scratches because they can create data errors. If you notice problems such as skipping or degraded playback quality with your CDs or DVDs, clean the discs. Commercial products are available that clean discs and provide protection from dust, fingerprints, and scratches. Cleaning products for CDs are safe to use on DVDs.
Hold the disc by the outer edge or by the inside edge.
Gently wipe the disc with a lint-free cotton cloth. Never use paper or any material that can scratch the disc or leave streaks.
Wipe from the center of the disc outward. Never use a circular motion.
Apply a commercial CD or DVD cleaning solution to the lint-free cotton cloth, and wipe again if any contaminates remain on the disc.
Allow the disc to dry before it is inserted into the drive.
An optimal operating environment for a laptop is clean, free of potential contaminants, and within the temperature and humidity range specified by the manufacturer. Figure 1 shows examples of operating environments. With most desktop computers, the operating environment can be controlled. However, due to the portable nature of laptops, it is not always possible to control the temperature, humidity, and working conditions. Laptops are built to resist adverse environments, but technicians should always take precautions to protect the equipment from damage and loss of data.
It is important to transport or ship laptops carefully. Use a padded laptop case to store your laptop. When you carry it, use an approved computer bag. If the laptop is shipped, use sufficient packing material. Figure 2 shows examples of laptop carrying cases and packing boxes.
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Laptops are transported to many types of environments. Dust particles, temperature, and humidity can affect the performance of a laptop.
Follow these guidelines to help ensure optimal operating performance from your laptop:
Clean the laptop frequently to remove dust and potential contaminants.
Do not obstruct vents or airflow to internal components. A laptop can overheat if air circulation is obstructed.
Keep the room temperature between 45 to 90 degrees Fahrenheit (7 to 32 degrees Celsius).
Keep the humidity level between 10 to 80 percent.
CAUTION: Use a soft, lint-free cloth with an approved cleaning solution to avoid damaging laptop surfaces. Apply the cleaning solution to the lint-free cloth, not directly to the laptop.
Temperature and humidity recommendations vary by laptop manufacturer. You should research these recommended values, especially if you plan to use the laptop in extreme conditions. Refer to Figure 3 for humidity and temperature examples.
When troubleshooting problems with laptops or portable devices, you should determine if a repair is cost-effective. To determine the best course of action, compare the cost of the repair with the replacement cost of the laptop or portable device, less the salvage value.
Because many portable devices change rapidly in design and functionality, they are often more expensive to repair than to replace. For this reason, portable devices are usually replaced, whereas laptops can be replaced or repaired.
Follow the steps outlined in this section to accurately identify, repair, and document the problem. The troubleshooting process is shown in Figure 1.
After completing this section, you will meet these objectives:
Review the troubleshooting process.
Identify common problems and solutions.
Computer problems can result from a combination of hardware, software, and network issues. Computer technicians must be able to analyze the problem and determine the cause of the error to repair the computer. This process is called troubleshooting.
The first step in the troubleshooting process is to identify the problem. Figure 1 is a list of open-ended and closed-ended questions to ask the customer.
After you have talked to the customer, you can establish a theory of probable causes. Figure 2 is a list of some common probable causes for printer problems.
After you have developed some theories about what is wrong, test your theories to determine the cause of the problem. Figure 3 is a list of quick procedures that can determine the exact cause of the problem or even correct the problem. If a quick procedure does correct the problem, you can go to step 5 to verify full system functionality. If a quick procedure does not correct the problem, you may need to research the problem further to establish the exact cause.
After you have determined the exact cause of the problem, establish a plan of action to resolve the problem and implement the solution. Figure 4 shows sources of information to gather additional information to resolve an issue.
After you have corrected the problem, verify full functionality and, if applicable, implement preventive measures. Figure 5 is a list of the steps to verify the solution.
In the final step of the troubleshooting process, you must document your findings, actions, and outcomes. Figure 6 is a list of the tasks required to document the problem and the solution.
Computer problems can be attributed to hardware, software, networks, or some combination of the three. You will resolve some types of computer problems more often than others. Figure 1 is a chart of common laptop problems and solutions.
Chapter 7
This chapter provides essential information about printers and scanners. You will learn how printers operate, what to consider when purchasing a printer, and how to connect printers to an individual computer or to a network.
Printers produce paper copies of electronic files. Scanners allow users to convert paper documents into electronic files. Many government regulations require physical records; therefore, hard copies of computer documents are often as important today as they were when the paperless revolution began several years ago.
You must understand the operation of various types of printers and scanners to be able to install and maintain them, as well as troubleshoot any problems that arise.
After completing this chapter, you will meet these objectives:
Describe the types of printers currently available.
Describe the installation and configuration process for printers.
Describe the types of scanners currently available.
Describe the installation and configuration process for scanners.
Identify and apply common preventive maintenance techniques for printers and scanners.
Troubleshoot printers and scanners.
As a computer technician, you might be required to purchase, repair, or maintain a printer. The customer might request that you perform the following tasks:
Select a printer.
Install and configure a printer.
Troubleshoot a printer.
After completing this section, you will meet these objectives:
Describe characteristics and capabilities of printers.
Describe printer-to-computer interfaces.
Describe laser printers.
Describe impact printers.
Describe inkjet printers.
Describe solid-ink printers.
Describe other printer types.
Printers available today are usually either laser printers using electrophotographic technology or inkjet printers using electrostatic spray technology. Dot matrix printers using impact technology are used in applications that require carbon copies. Figure 1 shows a list of printer selection criteria.
Capacity and Speed
Printer capacity and speed are factors to consider when selecting a printer. Inkjet printers are usually slower, but they might be adequate for a home or small office. The speed of a printer is measured in pages per minute (ppm). The speed of an inkjet printer is 2–6 ppm. The speed of a laser printer is 8–200 ppm.
Color or Black and White
A computer monitor produces colors through the additive mixing of dots that are displayed on the screen. The eye picks up the colors directly. The dots produce the color range using red, green, and blue (RGB) dots.
A printer produces colors using subtractive mixing. The eye sees a color that reflects from the combination of colors on the paper. Figure 2 shows a CMYK color wheel.
The choice between a black-and-white printer and a color printer depends on the needs of your customer. If your customer is primarily printing letters and does not need color capability, a black-and-white printer is sufficient. However, an elementary school teacher might need a color printer to add excitement to lessons.
Quality
The quality of printing is measured in dots per inch (dpi). The more dpi, the higher the resolution. When the resolution is higher, text and images are usually clearer. To produce the best high-resolution images, you should use both high-quality ink or toner and high-quality paper.
Reliability
A printer should be reliable. Because there are so many types of printers on the market, research the specifications of several printers before selecting one. Here are some of the options available from the manufacturer:
Warranty – Identify what is covered within the warranty.
Scheduled servicing – Servicing is based on expected usage. Information is found in the manual or on the manufacturer's website.
Mean time between failures (MTBF) – There is an average length of time that the printer works without failing. Information is found in the manual or on the manufacturer's website.
Total Cost of Ownership
Consider the cost when selecting hardware. When buying a printer, there is more than just the initial cost of the printer to consider. The total cost of ownership (TCO) includes a number of factors:
Initial purchase price
Cost of supplies, such as paper and ink
Price per page
Maintenance costs
Warranty costs
When calculating the TCO, you should also consider the amount of material printed and the expected lifetime of the printer.
A computer must have a compatible interface with the printer to be able to print documents. Typically, printers connect to home computers using a parallel, USB, or wireless interface. Corporate printers might connect to a network using a network cable.
Serial
Serial data transfer is the movement of single bits of information in a single cycle. A serial connection can be used for dot matrix printers because the printers do not require high-speed data transfer.
Parallel
Parallel data transfer is faster than serial data transfer. Parallel data transfer is the movement of multiple bits of information in a single cycle. The path is wider for information to move to or from the printer.
IEEE 1284 is the current standard for parallel printer ports. Enhanced Parallel Port (EPP) and Enhanced Capabilities Port (ECP) are two modes of operation within the IEEE 1284 standard that allow bi-directional communication.
SCSI
Small Computer System Interface (SCSI) is a type of interface that uses parallel communication technology to achieve high data-transfer rates.
USB
USB is a common interface for printers and other devices. The speed and simple setup has made USB very practical. Newer operating systems offer PnP USB support. When a USB device is added to a computer system supporting PnP, the device is automatically detected and starts the driver installation process.
FireWire
FireWire, also known as i.LINK or IEEE 1394, is a high-speed communication bus that is platform independent. FireWire connects digital devices such as digital printers, scanners, digital cameras, and hard drives.
FireWire allows a peripheral device, such as a printer, to seamlessly plug into a computer. It also allows a device such as printer to be hot-swappable. FireWire provides a single plug-and-socket connection that can attach up to 63 devices. FireWire has a data transfer rate of up to 400 Mbps.
Ethernet
Printers can be shared over a network. Connecting a printer to the network requires cabling that is compatible with both the existing network and the network port installed in the printer. Most network printers use an RJ-45 interface to connect to a network.
Wireless
Wireless printing technology is available in infrared, Bluetooth, and wireless fidelity (Wi-Fi) technology.
For infrared communication to take place between a printer and a computer, transmitters and receivers are required on both devices. There must be a clear line of sight between the transmitter and receiver on both devices, with a maximum distance of 12 feet (3.7 m). Infrared uses a type of light that is invisible to the human eye.
Bluetooth technology uses an unlicensed radio frequency for short-range communication and is popular for wireless headsets and synching PDAs to laptops and desktop computers. A Bluetooth adapter allows a Bluetooth device to connect to a printer, usually by using a USB port.
Wi-Fi is the popular name for a relatively new technology that allows the connection of computers to a network without using cables. There are two common standards for Wi-Fi technology, both of which begin with the number of the IEEE standard 802.11:
802.11b transfers data at a rate of 11 Mbps.
802.11g transfers data at a rate of 54 Mbps. 802.11g products are backward-compatible with 802.11b.
A laser printer is a high-quality, fast printer that uses a laser beam to create an image. The central part of the laser printer is its electrophotographic drum. The drum is a metal cylinder that is coated with a light-sensitive insulating material. When a beam of laser light strikes the drum, it becomes a conductor at the point where the light hits it. As the drum rotates, the laser beam draws an electrostatic image upon the drum, called the image. The undeveloped or latent image is passed by a supply of dry ink or toner that is attracted to it. The drum turns and brings this image in contact with the paper, which attracts the toner from the drum. The paper is passed through a fuser that is made up of hot rollers, which melts the toner into the paper.
Printing Process
The laser printer process involves six steps to print information onto a single sheet of paper.
Step 1: Cleaning
When an image has been deposited on the paper and the drum has separated from the paper, any remaining toner must be removed from the drum. A printer may have a blade that scrapes all excess toner from the drum. Some printers use an AC voltage on a wire that removes the charge from the drum surface and allows the excess toner to fall away from the drum. The excess toner is stored in a used toner container that is either emptied or discarded.
Step 2: Conditioning
This step involves removing the old latent image from the drum and conditioning the drum for a new latent image. Conditioning is done by placing a special wire, grid, or roller that receives a negative charge of approximately –600 volts DC uniformly across the surface of the drum. The charged wire or grid is called the primary corona. The roller is called a conditioning roller.
Step 3: Writing
The writing process involves scanning the photosensitive drum with the laser beam. Every portion of the drum that is exposed to the light has the surface charge reduced to about –100 volts DC. This electrical charge has a lower negative charge than the remainder of the drum. As the drum turns, an invisible latent image is created on the drum.
Step 4: Developing
In the developing phase, the toner is applied to the latent image on the drum. The toner is a negatively-charged combination of plastic and metal particles. A control blade holds the toner at a microscopic distance from the drum. The toner then moves from the control blade to the more positively-charged latent image on the drum.
Step 5: Transferring
In this step, the toner attached to the latent image is transferred to the paper. The transfer, or secondary corona, places a positive charge on the paper. Because the drum was charged negatively, the toner on the drum is attracted to the paper. The image is now on the paper and is held in place by the positive charge.
Step 6: Fusing
In this step, the toner is permanently fused to the paper. The printing paper is rolled between a heated roller and a pressure roller. As the paper moves through the heated roller and the pressure roller, the loose toner is melted and fused with the fibers in the paper. The paper is then moved to the output tray as a printed page.
The following mnemonic can help you memorize the order of the steps of the laser printing process: Continuous Care Will Delay Trouble Forever (Cleaning, Conditioning, Writing, Developing, Transferring, Fusing).
WARNING: The primary corona wire or grid, or the conditioning roller, can be very dangerous. The voltage runs as high as –6000 volts. Only certified technicians should work on the unit. Before working inside a laser printer, you should make sure that voltage is properly discharged.
Impact printers are very basic printers. Impact printers have print heads that strike the inked ribbon, causing characters to be imprinted on the paper. Dot matrix and daisy wheel are examples of impact printers.
The following are some advantages of an impact printer:
Uses inexpensive consumables
Uses continuous feed paper
Has carbon-copy printing ability
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The following are some disadvantages of an impact printer:
Noisy
Low-resolution graphics
Limited color capability
Slow printing, normally in the range of 32 to 76 characters per second (cps)
Types of Impact Printers
In the daisy wheel printer, the wheel contains the letters, numbers, and special characters. The wheel is rotated until the required character is in place, and an electromechanical hammer pushes the character into the ink ribbon. The character then strikes the paper, imprinting the character on the paper.
The dot matrix printer is similar to the daisy wheel printer, except that instead of a wheel containing the characters, a print head contains pins that are surrounded by electromagnets. When energized, the pins push forward onto the ink ribbon, creating a character on the paper.
The number of pins on a print head, 9 or 24, indicates the quality of the print. The highest quality of print that is produced by the dot matrix printer is referred to as near letter quality (NLQ).
Most dot matrix printers use continuous feed paper. The paper has perforations between each sheet and perforated strips on the side used to feed the paper and to prevent skewing or shifting. Sheet feeders that print one page at a time are available in some of the higher-quality office printers. A large roller, called the platen, applies pressure to keep the paper from slipping. If a multiple-copy paper is used, the platen gap can be adjusted to the thickness of the paper.
Inkjet printers produce high-quality prints. Inkjet printers are easy to use and inexpensive compared to laser printers. The print quality of an inkjet printer is measured in dots per inch (dpi). Higher dpi numbers provide greater image details. Figure 1 shows an all-in-one device that contains an inkjet printer. Figure 2 shows ink jet printer components.
Inkjet printers use ink-filled cartridges that spray ink onto a page through tiny holes. The tiny holes are called nozzles. The ink is sprayed in a pattern on the page.
There are two types of inkjet nozzles:
Thermal – A pulse of electrical current is applied to heating chambers around the nozzles. The heat creates a bubble of steam in the chamber. The steam forces ink out through the nozzle and onto the paper.
Piezoelectric – Piezoelectric crystals are located in the ink reservoir at the back of each nozzle. A charge is applied to the crystal, causing it to vibrate. This vibration of the crystal controls the flow of ink onto the paper.
Inkjet printers use plain paper to make economical prints. Special-purpose paper can be used to create high-quality prints of photographs. When the inkjet print is complete and the paper leaves the printer, the ink is often wet. You should avoid touching printouts for 10 to 15 seconds to prevent the images from smearing.
These are some advantages of an inkjet printer:
Low cost
High resolution
Quick to warm up
These are some disadvantages of an inkjet printer:
Nozzles are prone to clogging.
Ink cartridges are expensive.
Ink is wet after printing.
Solid-ink printers use solid sticks of ink rather than toner or ink cartridges. Solid-ink printers produce high-quality images. The ink sticks are nontoxic and can be handled safely.
Solid-ink printers melt ink sticks and spray the ink through nozzles. The ink is sprayed onto a drum. The drum transfers the ink to paper.
These are some advantages of solid-ink printers:
Produces vibrant color prints
Easy to use
Can use many different paper types
These are some disadvantages of solid-ink printers:
Printers are expensive.
Ink is expensive.
They are slow to warm up.
Two other printing technologies that you might work with are thermal and dye-sublimation.
Thermal Printers
Some retail cash registers or older fax machines might contain thermal printers, as shown in Figure 1. The thermal paper used in thermal printers is chemically treated and has a waxy quality. Thermal paper becomes black when heated. Most thermal printer print heads are the width of the paper. Areas of the print head are heated as required to make the pattern on the paper. The paper is supplied in the form of a roll.
A thermal printer has the following advantage:
Longer life because there are few moving parts
A thermal printer has the following disadvantages:
Paper is expensive.
Paper has a short shelf life.
Images are poor quality.
Paper must be stored at room temperature.
Dye-Sublimation Printers
Dye-sublimation printers produce photo-quality images for graphic printing. See Figure 2 for an example of a dye-sublimation printer. This type of printer uses solid sheets of ink that change directly from solid to gas in a process called sublimating. The print head passes over a sheet of cyan, magenta, yellow, and a clear overcoat (CMYO). There is a pass for each color.
Dye-sublimation printers have the following advantages:
Printers produce high-quality images.
Overcoat layer reduces smearing and increases moisture resistance.
Dye-sublimation printers have the following disadvantages:
Media can be expensive.
Printers are better for color than for grayscale (black and white).
In photography, both dye-sublimation printers and small color ink-jet printers provide quality prints.
When you purchase a printer, the installation and configuration information is usually supplied by the manufacturer. An installation CD that includes drivers, manuals, and diagnostic software is included with the printer. The same tools might also be available as downloads from the manufacturer's website.
After completing this section, you will meet these objectives:
Describe how to set up a printer.
Explain how to power and connect the device using a local or network port.
Describe how to install and update the device driver, firmware, and RAM.
Identify configuration options and default settings.
Describe how to optimize printer performance.
Describe how to print a test page.
Describe how to share a printer.
Although all types of printers are somewhat different to connect and configure, there are procedures that should be applied to all printers. After the printer has been unpacked and placed in position, connect it to the computer, network, or print server and plug it into an electrical outlet. Remove all packing materials, such as plastic inserts and tape, from the toner or ink cartridge. Install the toner or ink cartridge in the printer. Insert the paper, labels, or envelopes into the paper tray and attach the paper tray to the printer.
Now that the printer has been unpacked and placed in position, you must connect it to the computer, network, or print server and plug it into an electrical outlet.
A printer can be connected and used as a local or network printer. A local printer is connected directly to a computer port, such as a USB, parallel, or serial port. The local computer manages and sends the print jobs to the printer. Local printers can be shared over the network with other users. A network printer is connected to a network using a wireless or an Ethernet connection. The network printer allows multiple users to send documents to the printer over the network.
After determining if the printer will be a local or a network printer, connect the appropriate data cable to the communication port on the back of the printer. If the printer has a USB, FireWire, or parallel port, connect the corresponding cable to the printer port. Connect the other end of the data cable to the corresponding port on the back of the computer. If you are installing a network printer, connect the network cable to the network port.
After the data cable has been properly connected, attach the power cable to the printer. Connect the other end of the power cable to an available electrical outlet.
Warning: Never plug a printer into a UPS. The power surge that occurs when the printer is turned on damages the UPS unit.
After you have connected the power and data cables to the printer, the operating system might discover the printer and attempt to install a driver. If you have a driver disc from the manufacturer, use this driver. The driver that is included with the printer is usually more current than the drivers used by the operating system. Figure 1 shows the Add Printer wizard, which can also be used to install the new printer.
Printer Driver
Printer drivers are software programs that enable the computer and the printer to communicate with each other. Drivers also provide an interface for the user to configure printer options. Every printer model has a unique driver. Printer manufacturers frequently update drivers to increase the performance of the printer, to add options, or to fix problems. You can download new printer drivers from the manufacturer's website.
Step 1: Find Out If a Newer Driver Is Available
Go to the printer manufacturer's website. Most manufacturers' websites have a link from the main page to a page that offers drivers and support. Make sure the driver is compatible with the computer that you are updating.
Step 2: Download the Driver
Download the printer driver files to your computer. Most driver files come in a compressed or "zipped" format. Download the file to a folder and uncompress or "unzip" the contents. Save instructions or documentation to a separate folder on your computer.
Step 3: Install the Downloaded Driver
Install the downloaded driver automatically or manually. Most printer drivers have a setup file that automatically searches the system for older drivers and replaces them with the new one. If no setup file is available, follow the directions that are supplied by the manufacturer.
Step 4: Test the New Printer Driver
Run multiple tests to make sure the printer works properly. Use a variety of applications to print different types of documents. Change and test each printer option.
Firmware
Firmware is a set of instructions stored on the printer. The firmware controls how the printer operates. The procedure to upgrade firmware is very similar to the procedure for installing printer drivers.
Printer Memory
Adding printer memory to a printer can improve printing speed and allow the printer to handle more complex print jobs. All printers have at least some amount of memory inside. Generally, the more memory a printer has, the more efficiently it operates. Figure 2 is a generic list of steps to follow to upgrade printer memory.
Consult the printer documentation for memory requirements:
Memory specifications – Some printer manufacturers use standard types of memory and other manufacturers use proprietary memory. Check the documentation for the type of memory, the speed of the memory, and the capacity of memory.
Memory population and availability – Some printers have multiple memory slots. To find out how many memory slots are used and how many are available, you might need to open a compartment on the printer to check memory population.
Each printer might have different configurations and default options. Check the printer documentation for information about configurations and default settings.
Here are some common configurations that are available for printers:
Paper type – standard, draft, gloss, or photo
Print quality – draft, normal, photo, or automatic
Color printing – multiple colors used
Black-and-white printing – only black ink used
Grayscale printing – color image printed using only black ink in different shades
Paper size – standard paper sizes or envelopes and business cards
Paper orientation – landscape or portrait
Print layout – normal, banner, booklet, or poster
Duplex – normal or two-sided printing
With printers, most optimization is completed through the software supplied with the drivers.
In the software, there are tools available to optimize performance:
Print spool settings – Cancel or pause current print jobs in the printer queue
Color calibration – Adjust settings to match the colors on the screen to the colors on the printed sheet
Paper orientation – Select landscape or portrait image layout
After installing a printer, you should print a test page to verify that the printer is operating properly. The test page confirms that the driver software is installed and working correctly, and that the printer and computer are communicating.
Print a Test Page
To manually print a test page in Windows XP, use the following path:
Start > Printers and Faxes to display the Printers and Faxes menu.
To manually print a test page in Windows Vista, use the following path:
Start > Printers to display the Printers and Faxes menu.
In the Printers and Faxes menu, right-click the desired printer and follow this path:
Properties > General Tab > Print Test Page
A dialog box opens, asking if the page printed correctly. If the page did not print, built-in help files assist you in troubleshooting the problem.
Print from an Application
You can also test a printer by printing a test page from an application such as Notepad or WordPad. To access Notepad in Windows XP, use the following path:
Start > All Programs > Accessories > Notepad
To access Notepad in Windows Vista, use the following path:
Start > All Programs > Accessories > Notepad
In the blank document that opens, type some text. Print the document using the following path:
File > Print
Test a Printer
You can also print from the command line to test the printer. Printing from the command line is limited to ASCII files only, such as .txt and .bat files. To send a file to the printer from the command line in Windows XP, use this path:
Start > Run
To send a file to the printer from the command line in Windows Vista, use this path:
Start > Start Search
In the Run box, type cmd and then click OK.
At the command line prompt, enter the following command:
Print thefile.txt
Test the Printer from the Printer Panel
Most printers have a front panel with controls to allow you to generate test pages. This method of printing enables you to verify the printer operation separately from the network or computer. Consult the printer manufacturer's website or documentation to learn how to print a test page from the front panel of the printer.
Printer sharing enables multiple users or clients to access a printer that they are not directly connected to. Figure 1 shows several computers with different operating systems, all connected to the same shared printer. This arrangement reduces the expense on a network, because fewer printers are required.
Witpowv64 – iptpdfmtosk
WtfaafsdiowXP – FAT32, NTFS
Setting up printer sharing is simple with Windows XP and Windows Vista. The following steps enable a computer to share a printer:
In Windows XP, click Start > Printers and Faxes. In Windows Vista, click Start > Control Panel > Printers.
Right-click the printer and choose Properties.
Select the Share tab.
Click the Share this printer radio button, as shown in Figure 2.
Keep or change the share name.
Click Apply.
All of the computers that use the shared printer must have the correct drivers installed. Drivers for other operating systems can be installed on the print server.
To connect to the printer from another computer on the network in Windows XP, choose Start > Printers and Faxes > Add Printer. In Windows Vista, choose Start > Control Panel > Printers > Add Printer. The Add Printer Wizard appears. Follow the steps using the wizard.
As a computer technician, you might be required to purchase, repair, or maintain a scanner. The customer might request you to perform the following tasks:
Select a scanner.
Install and configure a scanner.
Troubleshoot a scanner.
Figure 1 shows some of the different types of scanners.
After completing this section, you will meet the following objectives:
Describe scanner types, resolution, and interfaces.
Describe all-in-one devices.
Describe flatbed scanners.
Describe handheld scanners.
Describe drum scanners.
Compare costs of different types of scanners.
Scanners convert printed data or images into an electronic data format that a computer can store or process as required. After an image has been scanned, it can be saved, modified, and even e-mailed. Although most scanners perform the same operation, different types of scanners are available, as shown in Figure 1. Click on each type of scanner to learn more information.
As with printers, the features, quality, and speed of the different types of scanners vary. Scanners typically create an RGB image that can be converted into common image formats such as JPEG, TIFF, BMP, and PNG. An RGB image has three channels: red, green, and blue. RGB channels generally follow the color receptors of the human eye and are used in computer displays and image scanners.
Some scanners have the ability to create text documents using optical character recognition (OCR) software. OCR software converts a scanned printed page into text that can be edited with a word processor. The resolution of a scanner is measured in dots per inch (dpi). Like printers, the higher the dpi, the better the quality of the image.
To allow communication of data, the scanner and computer must have compatible interfaces. The interfaces and cables used for printers are typically the same as the interfaces and cables used for scanners, as shown in Figure 2.
An all-in-one device combines the functionality of multiple devices into one physical piece of hardware. The devices may include media card readers and hard drives for storage. All-in-one devices generally include these functions:
Scanner
Printer
Copier
Fax
All-in-one devices are typically used in home-office environments or where space is limited. These devices are often used with a computer but can operate alone to copy and fax documents.
Flatbed scanners are often used to scan books and photographs for archiving. An electronic image is acquired by placing the book or photograph face down on the glass. The scanner head, consisting of an array of image sensors, lies beneath the glass and moves along the item, capturing the image.
Sheet feeders can be used with flatbed scanners to scan multiple images. A sheet feeder is a device that can be attached to some flatbed scanners to hold multiple sheets and feed them into the scanner, one at a time. This feature allows for faster scanning; however, the image quality is usually not as good as a flatbed scanner that does not use a sheet feeder.
A handheld scanner is small and portable. It is difficult to smoothly scan an image using a handheld scanner. To scan an item, carefully pass the scanner head across the item that you want to scan. As with a flatbed scanner, digital images are made from the images collected by the handheld scanner.
When you want to scan an item larger than the head of the handheld scanner, you must make more than one pass to capture the full image. It may be difficult to recreate the original image digitally when it is scanned in more than one pass. The images must be put back together to form a single image of the item that was scanned.
Drum scanners produce a high-quality transfer of an image. Drum scanners are usually used commercially but are being replaced by lower-priced, high-quality flatbed scanners. Many drum scanners are still in use for high-end reproductions, such as archiving photographs in museums.
To scan an image using a drum scanner, you attach the image to a revolving drum or load it into a supporting canister. The drum is rotated at high speed across optical scanners. The optical scanners move slowly across the drum surface until the entire image is captured. The captured image is then reproduced by the computer as a digital image file.
When you purchase a scanner, the installation and configuration information is usually supplied by the manufacturer. An installation CD that includes drivers, manuals, and diagnostic software is included with the scanner. The same tools might also be available as downloads from the manufacturer's website.
After completing this section, you will meet the following objectives:
Explain how to power and connect a scanner.
Describe how to install and update the device driver.
Identify configuration options and default settings.
Like printers, scanners can connect to a computer using the USB, FireWire, network, or parallel port interface. Some scanners can connect using a SCSI interface.
Scanners that are built into an all-in-one device are plugged directly into an AC wall outlet. Other types of scanners acquire power through the USB or FireWire connector.
After unpacking the scanner, connect the appropriate power and data cables. Use the scanner documentation as your guide, or check the manufacturer's website for instructions.
After you have connected and started the scanner, the computer operating system might be able to discover the scanner through the PnP process. If the scanner is discovered, the operating system might automatically install a driver.
After you set up a scanner, install the driver software that the manufacturer includes with the scanner. This driver is usually more current than the drivers on your computer. It might also provide more functionality than the basic driver from Windows.
As with a printer, you might want to install drivers from the manufacturer's website to gain additional functionality, diagnostic tools, and troubleshooting utilities. Download software from the manufacturer's website and follow any directions provided to install the software and utilities for your scanner. Some scanning software automatically downloads and installs updated software, drivers, or firmware. Follow the directions provided by the update utility to install these files.
Scanners have configuration options and default settings that differ between model types and manufacturers.
A scanner might come with a basic graphic editing software package for editing photographs and other images. Editing software packages might include OCR software that allows text in a scanned image to be manipulated as text.
These are some of the configurations that might be available on a scanner:
Color, grayscale, or black-and-white scanning
One-touch scanning into your choice of software
Quality and resolution choices
Sheet feeders
Color calibration between devices is important so that you see true representations of color. To calibrate a scanner, scan a graphic that contains specific colors. A calibration application installed on the computer compares the output of the scanner against the known colors of the sample graphic on the display. The software adjusts the color of the scanner accordingly. When your scanner, monitor, and printer treat the same colors in the same way, the image you print matches the image you scan.
Printers and scanners have many moving parts that can wear out over time or through extended use. They must be maintained regularly to operate correctly.
Moving parts can be affected by dust and other air particles. Clean printers and scanners regularly to avoid downtime, loss of productivity, and high repair costs.
After completing this section, you will meet the following objectives:
Describe printer maintenance.
Describe scanner maintenance.
Printers have many moving parts and require a higher level of maintenance than most other electronic devices. Impurities are produced by the printer and collect on the internal components. Over time, if the impurities are not removed, the printer can malfunction. The maintenance schedule for a printer can be found in the manual or on the manufacturer's website.
CAUTION: Be sure to unplug the printer from the electrical source before beginning any type of maintenance.
Most printers come with printer monitoring and diagnostic software from the manufacturer that can help you maintain the printer. Observe the guidelines from the manufacturer for cleaning the following printer and scanner components:
Printer roller surfaces
Printer and scanner paper-handling mechanisms
The type and quality of paper and ink used can affect the life of the printer:
Paper selection – High-quality paper can help to ensure that the printer operates efficiently and for a long time. Many types of printer paper are available, including inkjet and laser. The printer manufacturer might recommend the type of paper to use for best results. Some papers, especially photo paper and transparencies, have a right and wrong side. Load the paper according to the manufacturer's instructions.
Ink selection – The manufacturer recommends the brand and type of ink to use. If the wrong type of ink is installed, the printer might not work or the print quality might deteriorate. You should avoid refilling the ink cartridges because the ink can leak.
The scanner surface should be kept clean. If the glass becomes dirty, consult the manufacturer's user manual for cleaning recommendations. To prevent liquid from leaking into the scanner case, do not spray glass cleaner directly on the device. Dampen a cloth with the cleaner, and then apply the cleaner gently to the glass.
If the inside of the glass becomes dirty, check the manual for instructions on how to open the unit or remove the glass from the scanner. If possible, thoroughly clean both sides of the glass, and replace the glass as it was originally set in the scanner. When the scanner is not in use, keep the lid closed. Put handheld scanners in a safe place. Also, never lay anything heavy on a scanner because you can damage the casing or internal parts.
With printer and scanner problems, a technician must be able to determine if the problem exists with the device, cable connection, or the computer that it is attached to. Follow the steps outlined in this section to accurately identify, repair, and document the problem.
After completing this section, you will meet these objectives:
Review the troubleshooting process.
Identify common problems and solutions.
Printer problems can result from a combination of hardware, software, and network issues. Computer technicians must be able to analyze the problem and determine the cause of the error to repair the printer. This process is called troubleshooting.
The first step in the troubleshooting process is to identify the problem. Figure 1 is a list of open-ended and closed-ended questions to ask the customer.
After you have talked to the customer, you can establish a theory of probable causes. Figure 2 is a list of some common probable causes for printer problems.
After you have developed some theories about what is wrong, test your theories to determine the cause of the problem. Figure 3 is a list of quick procedures that can determine the exact cause of the problem or even correct the problem. If a quick procedure does correct the problem, you can go to step 5 to verify full system functionality. If a quick procedure does not correct the problem, you might need to research the problem further to establish the exact cause.
After you have determined the exact cause of the problem, establish a plan of action to resolve the problem and implement the solution. Figure 4 shows sources of information to gather additional information to resolve an issue.
After you have corrected the problem, verify full functionality and, if applicable, implement preventive measures. Figure 5 is a list of the steps to verify the solution.
In the final step of the troubleshooting process, you must document your findings, actions, and outcomes. Figure 6 is a list of the tasks required to document the problem and the solution.
Printer or scanner problems can be attributed to hardware, software, networks, or some combination of the three. You will resolve some types of printer and scanner problems more often than others. Figure 1 is a chart of common printer and scanner problems and solutions.
In this chapter, various types of printers and scanners were discussed. You learned that there are many different types and sizes of printers and scanners, each with different capabilities, speeds, and uses. You also learned that both printers and scanners can be connected directly to computers, as well as shared across a network. The chapter also introduced the different types of cables and interfaces available to connect a printer or scanner. The following concepts from this chapter are important to remember:
Some printers and scanners have low output and are adequate for home use, whereas other printers and scanners have high output and are designed for commercial use.
Printers can have different speeds and quality of print.
Older printers and scanners use parallel cables and ports. Newer printers and scanners typically use USB or FireWire cables and connectors.
Larger printers and scanners might also have an NIC port to connect to a network.
Newer printers and scanners are PnP. The computer automatically installs the necessary drivers.
If the device drivers are not automatically installed by the computer, you must supply the drivers on a CD or download them from the manufacturer's website.
Most optimization is done through software drivers and utilities.
After you have set up the printer or scanner, you can share the device with other users on the network. This arrangement is cost-efficient because there is no need for every user to have a printer or scanner.
A good preventive maintenance program extends the life of the printer and scanner and keeps them performing well.
Troubleshooting printer and scanner problems requires the technician to identify, repair, and document the problem.
Troubleshooting steps include: identify the problem, establish a theory of probable causes, determine an exact cause, implement a solution, verify solution and full system functionality, and document findings.
Chapter 8
Networks are systems that are formed by links. Websites that allow individuals to link to each other’s pages are called social networking sites. A set of related ideas can be called a conceptual network. The connections you have with all your friends can be called your personal network.
People use the following networks every day:
Mail delivery system
Telephone system
Public transportation system
Corporate computer network
The Internet
Computers can be linked by networks to share data and resources. A network can be as simple as two computers connected by a single cable or as complex as hundreds of computers connected to devices that control the flow of information. Converged data networks can include general purpose computers, such as PCs and servers, as well as devices with more specific functions, including printers, phones, televisions, and game consoles.
All data, voice, video, and converged networks share information and use various methods to direct how this information flows. The information on the network goes from one place to another, sometimes via different paths, to arrive at the appropriate destination.
The public transportation system is similar to a data network. The cars, trucks, and other vehicles are like the messages that travel within the network. Each driver defines a starting point (source) and an ending point (destination). Within this system, there are rules such as stop signs and traffic lights that control the flow from the source to the destination.
After completing this section, you will meet these objectives:
Define computer networks.
Explain the benefits of networking.
A computer data network is a collection of hosts connected by networking devices. A host is any device that sends and receives information on the network. Peripherals are devices that are connected to hosts. Some devices can serve either as hosts or peripherals. For example, a printer connected to your laptop that is on a network is acting as a peripheral. If the printer is connected directly to a networking device, such as a hub, switch, or router, it is acting as a host.
Computer networks are used globally in businesses, homes, schools, and government agencies. Many of the networks are connected to each other through the Internet.
Many different types of devices can connect to a network:
Desktop computers
Laptop computers
Printers
Scanners
PDAs
Smartphones
File and print servers
A network can share many different types of resources:
Services, such as printing or scanning
Storage space on removable devices, such as hard drives or optical drives
Applications, such as databases
You can use networks to access information stored on other computers, print documents using shared printers, and synchronize the calendar between your computer and your Smartphone.
Network devices link together using a variety of connections:
Copper cabling – Uses electrical signals to transmit data between devices
Fiber-optic cabling – Uses glass or plastic wire, also called fiber, to carry information as light pulses
Wireless connection – Uses radio signals, infrared technology, or satellite transmissions
The benefits of networking computers and other devices include lower costs and increased productivity. With networks, resources can be shared, which results in less duplication and corruption of data.
Fewer Peripherals Needed
Figure 1 shows that many devices can be connected on a network. Each computer on the network does not need to have its own printer, scanner, or backup device. Multiple printers can be set up in a central location and shared among the network users. All network users send print jobs to a central print server that manages the print requests. The print server can distribute print jobs over multiple printers or queue jobs that require a specific printer.
Increased Communication Capabilities
Networks provide several different collaboration tools that can be used to communicate between network users. Online collaboration tools include e-mail, forums and chats, voice and video, and instant messaging. With these tools, users can communicate with friends, family, and colleagues.
Avoid File Duplication and Corruption
A server manages network resources. Servers store data and share it with users on a network. Confidential or sensitive data can be protected and shared with the users who have permission to access that data. Document tracking software can be used to prevent users from overwriting files or changing files that others are accessing at the same time.
Lower Cost Licensing
Application licensing can be expensive for individual computers. Many software vendors offer site licenses for networks, which can dramatically reduce the cost of software. The site license allows a group of people or an entire organization to use the application for a single fee.
Centralized Administration
Centralized administration reduces the number of people needed to manage the devices and data on the network, reducing time and cost to the company. Individual network users do not need to manage their own data and devices. One administrator can control the data, devices, and permissions of users on the network. Backing up data is easier because the data is stored in a central location.
Conserve Resources
Data processing can be distributed across many computers to prevent one computer from becoming overloaded with processing tasks.
Data networks continue to evolve in complexity, use, and design. To communicate about networks, different types of networks are given different descriptive names. A computer network is identified by the following specific characteristics:
The area it serves
How data is stored
How resources are managed
How the network is organized
Type of networking devices used
Type of media used to connect the devices
After completing this section, you will meet these objectives:
Describe a LAN.
Describe a WAN.
Describe a WLAN.
Explain peer-to-peer networks.
Explain client/server networks.
A LAN is a group of interconnected devices that is under the same administrative control. In the past, LANs were considered to be small networks that existed in a single physical location. Although LANs can be as small as a single local network installed in a home or small office, over time, the definition of LANs has evolved to include interconnected local networks consisting of many hundreds of devices, installed in multiple buildings and locations.
The important thing to remember is that all of the local networks within a LAN are under one administrative control group that governs the security and access control policies that are in force on the network. In this context, the word Local refers to local consistent control rather than being physically close to each other. Devices in a LAN might be physically close, but this is not a requirement.
A WAN is a network that connects LANs in geographically separated locations. The most common example of a WAN is the Internet. The Internet is a large WAN that is composed of millions of interconnected LANs. Telecommunications service providers are used to interconnect these LANs at different locations.
In a traditional LAN, devices are connected together using copper cabling. In some environments, installing copper cabling might not be practical, desirable, or even possible. In these situations, wireless devices are used to transmit and receive data using radio waves. These networks are called wireless LANs, or WLANs. As with LANs, on a WLAN you can share resources, such as files and printers, and access the Internet.
In a WLAN, wireless devices connect to access points within a specified area, as shown in Figure 1. Access points are typically connected to the network using copper cabling. Instead of providing copper cabling to every network host, only the wireless access point is connected to the network with copper cabling. The range (radius of coverage) for typical WLAN systems varies from under 30m (98.4 ft.) indoors to much greater distances outdoors, depending on the technology used.
In a peer-to-peer network, there are no dedicated servers or hierarchy among the computers. In this type of network, each device has equivalent capabilities and responsibilities. Individual users are responsible for their own resources and can decide which data and devices to share. Because individual users are responsible for the resources on their own computers, the network has no central point of control or administration.
Peer-to-peer networks work best in environments with ten or fewer computers. Because individual users are in control of their own computers, there is no need to hire a dedicated network administrator.
Peer-to-peer networks have several disadvantages:
There is no centralized network administration, which makes it difficult to determine who controls resources on the network.
There is no centralized security. Each computer must use separate security measures for data protection.
The network becomes more complex and difficult to manage as the number of computers on the network increases.
There might be no centralized data storage. Separate data backups must be maintained. This responsibility falls on the individual users.
Peer-to-peer networks still exist inside larger networks today. Even on a large client network, users can still share resources directly with other users without using a network server. In your home, if you have more than one computer, you can set up a peer-to-peer network. You can share files with other computers, send messages between computers, and print documents to a shared printer.
In a client/server network, the client requests information or services from the server. The server provides the requested information or service to the client. Servers on a client/server network commonly perform some of the processing work for client machines, for example, sorting through a database before delivering only the records requested by the client.
One example of a client/server network is a corporate environment in which employees use a company e-mail server to send, receive, and store e-mail. The e-mail client on an employee computer issues a request to the e-mail server for any unread e-mail. The server responds by sending the requested e-mail to the client.
In a client/server model, network administrators maintain the servers. The network administrator implements data backups and security measures. The network administrator also controls user access to the network resources. All of the data on the network is stored on a centralized file server. A centralized print server manages shared printers on the network. Each user must provide an authorized username and password to gain access to network resources that each person is permitted to use.
A workgroup is a collection of workstations and servers on a LAN that are designed to communicate and exchange data with one another. Each workstation controls the user accounts, security information, and access to data and resources for that computer.
A domain is a group of computers and electronic devices with a common set of rules and procedures administered as a unit. A domain does not refer to a single location or specific type of network configuration. The computers in a domain are a logical grouping of connected computers that can be located in different locations in the world. A specialized server called a domain controller manages all security-related aspects of users and network resources, centralizing security and administration.
For data protection, an administrator performs a routine backup of all the files on the servers. If a computer crashes, or data is lost, the administrator can easily recover the data from a recent backup.
As a computer technician, you will be required to configure and troubleshoot computers on a network. To effectively configure a computer on the network, you should understand IP addressing, protocols, and other network concepts.
After completing this section, you will meet these objectives:
Explain bandwidth and data transmission.
Describe IP addressing.
Define DHCP.
Describe Internet protocols and applications.
Define ICMP.
Bandwidth is the amount of data that can be transmitted within a fixed time period. When data is sent over a computer network, it is broken up into small chunks called packets. Each packet contains headers. A header is information added to each packet that contains the source and destination of the packet. A header also contains information that describes how to put all of the packets back together again at the destination. The size of the bandwidth determines the amount of information that can be transmitted.
Bandwidth is measured in bits per second and is usually denoted by any of the following units of measure:
bps – bits per second
kbps – kilobits per second
Mbps – megabits per second
NOTE: 1 byte is equal to 8 bits, and is abbreviated with a capital letter B. 1 MBps is approximately 8 Mbps.
Figure 1 shows how bandwidth on a network can be compared to a highway. In the highway example, the cars and trucks represent the data. The number of lanes on the highway represents the amount of cars that could travel on the highway at the same time. An eight-lane highway can handle four times the number of cars that a two-lane highway can hold.
The amount of time it takes data to travel from source to destination is called latency. Like a car traveling across town that encounters stop lights or detours, data is delayed by network devices and cable length. Network devices add latency when processing and forwarding data. When surfing the Web or downloading a file, latency does not normally cause problems. Time critical applications, such as Internet telephone calls, video, and gaming, can be significantly affected by latency.
The data that is transmitted over the network can flow using one of three modes: simplex, half-duplex, or full-duplex.
Simplex
Simplex, also called unidirectional, is a single, one-way transmission. An example of simplex transmission is the signal that is sent from a TV station to your home TV.
Half-Duplex
When data flows in one direction at a time, it is known as half-duplex. With half-duplex, the channel of communications allows alternating transmission in two directions, but not in both directions simultaneously. Two-way radios, such as police or emergency communications mobile radios, work with half-duplex transmissions. When you press the button on the microphone to transmit, you cannot hear the person on the other end. If people at both ends try to talk at the same time, neither transmission gets through.
Full-Duplex
When data flows in both directions at the same time, it is known as full-duplex. Although the data flows in both directions, the bandwidth is measured in only one direction. A network cable with 100 Mbps in full-duplex mode has a bandwidth of 100 Mbps.
A telephone conversation is an example of full-duplex communication. Both people can talk and be heard at the same time.
Full-duplex networking technology increases network performance because data can be sent and received at the same time. Broadband technology allows multiple signals to travel on the same wire simultaneously. Broadband technologies, such as digital subscriber line (DSL) and cable, operate in full-duplex mode. With a DSL connection, for example, users can download data to the computer and talk on the telephone at the same time.
An IP address is a number that is used to identify a device on the network. Each device on a network must have a unique IP address to communicate with other network devices. As noted earlier, a host is a device that sends or receives information on the network. Network devices are devices that move data across the network, including hubs, switches, and routers. On a LAN, each host and network device must have an IP address within the same network to be able to communicate with each other.
A person's name and fingerprints usually do not change. They provide a label or address for the physical aspect of the person – the body. A person's mailing address, on the other hand, relates to where the person lives or picks up mail. This address can change. On a host, the Media Access Control (MAC) address (explained below) is assigned to the host NIC and is known as the physical address. The physical address remains the same regardless of where the host is placed on the network in the same way that fingerprints remain with the person regardless of where the person goes.
The IP address is similar to the mailing address of a person. It is known as a logical address because it is logically assigned based on the host location. The IP address, or network address, is based on the local network and is assigned to each host by a network administrator. This process is similar to the local government assigning a street address based on the logical description of the city or village and neighborhood.
An IP address consists of a series of 32 binary bits (ones and zeros). It is very difficult for humans to read a binary IP address. For this reason, the 32 bits are grouped into four 8-bit bytes called octets. An IP address, even in this grouped format, is hard for humans to read, write, and remember; therefore, each octet is presented as its decimal value, separated by a decimal point or period. This format is referred to as dotted-decimal notation. When a host is configured with an IP address, it is entered as a dotted decimal number, such as 192.168.1.5. Imagine if you had to enter the 32-bit binary equivalent of this: 11000000101010000000000100000101. If just one bit were mistyped, the address would be different and the host might not be able to communicate on the network.
The logical 32-bit IP address is hierarchical and is composed of two parts. The first part identifies the network, and the second part identifies a host on that network. Both parts are required in an IP address. As an example, if a host has IP address 192.168.18.57, the first three octets, 192.168.18, identify the network portion of the address, and the last octet, 57 identifies the host. This is known as hierarchical addressing, because the network portion indicates the network on which each unique host address is located. Routers only need to know how to reach each network and not the location of each individual host.
IP addresses are divided into the following five classes:
Class A – Large networks, implemented by large companies and some countries
Class B – Medium-sized networks, implemented by universities
Class C – Small networks, implemented by ISPs for customer subscriptions
Class D – Special use for multicasting
Class E – Used for experimental testing
Subnet Mask
The subnet mask indicates the network portion of an IP address. Like the IP address, the subnet mask is a dotted decimal number. Usually all hosts within a LAN use the same subnet mask. Figure 1 shows the default subnet masks for usable IP addresses that are mapped to the first three classes of IP addresses:
255.0.0.0 – Class A, which indicates that the first octet of the IP address is the network portion
255.255.0.0 – Class B, which indicates that the first two octets of the IP address is the network portion
255.255.255.0 – Class C, which indicates that the first three octets of the IP address is the network portion
If an organization owns one Class B network but needs to provide IP addresses for four LANs, the organization must subdivide the Class B address into four smaller parts. Subnetting is a logical division of a network. It provides the means to divide a network, and the subnet mask specifies how it is subdivided. An experienced network administrator typically performs subnetting. After the subnetting scheme has been created, the proper IP addresses and subnet masks can be configured on the hosts in the four LANs. These skills are taught in the Cisco Networking Academy courses related to CCNA-level networking skills.
Manual Configuration
In a network with a small number of hosts, it is easy to manually configure each device with the proper IP address. A network administrator who understands IP addressing should assign the addresses and should know how to choose a valid address for a particular network. The IP address that is entered is unique for each host within the same network or subnet.
To manually enter an IP address on a host, go to the TCP/IP settings in the Properties window for the NIC. The NIC enables a computer to connect to a network using a MAC address. Whereas the IP address is a logical address that is defined by the network administrator, a MAC address is "burned-in" or permanently programmed into the NIC when it is manufactured. The IP address of a NIC can be changed, but the MAC address never changes.
The main difference between an IP address and a MAC address is that the MAC address delivers frames on the LAN, while an IP address transports frames outside the LAN. A frame is a data packet that, along with address information, is added to the beginning and end of the packet before transmission over the network. After a frame is delivered to the destination LAN, the MAC address delivers the frame to the end host on that LAN.
If more than a few computers comprise the LAN, manually configuring IP addresses for every host on the network can be time-consuming and prone to errors. In this case, the use of a Dynamic Host Configuration Protocol (DHCP) server would automatically assign IP addresses and greatly simplify the addressing process.
DHCP is a software utility used to dynamically assign IP addresses to network devices. This dynamic process eliminates the need for manually assigning IP addresses. A DHCP server can be set up and the hosts can be configured to automatically obtain an IP address. When a computer is set to obtain an IP address automatically, all of the other IP addressing configuration boxes are dimmed, as shown in Figure 1.
The server maintains a list of IP addresses to assign and manages the process so that every device on the network receives a unique IP address. Each address is held for a predetermined amount of time. When the time expires, the DHCP server can use this address for any computer that joins the network.
This is the IP address configuration information that a DHCP server can assign to hosts:
IP address
Subnet mask
Default gateway
Optional values, such as a Domain Name System (DNS) server address
The DHCP server receives a request from a host. The server then selects IP address information from a set of predefined addresses that are stored in a database. When the IP address information is selected, the DHCP server offers these values to the requesting host on the network. If the host accepts the offer, the DHCP server leases the IP address for a specific period of time.
Using a DHCP server simplifies the administration of a network because the software keeps track of IP addresses. Automatically configuring TCP/IP also reduces the possibility of assigning duplicate or invalid IP addresses. Before a computer on the network can take advantage of the DHCP server services, the computer must be able to identify the server on the local network. A computer can be configured to accept an IP address from a DHCP server by clicking the "Obtain an IP address automatically" option in the NIC configuration window, as shown in Figure 2. The DHCP settings are configured the same when using either a wired or wireless NIC.
If your computer cannot communicate with the DHCP server to obtain an IP address, the Windows operating system automatically assigns a private IP address. If your computer is assigned an IP address in the range of 169.254.0.0 to 169.254.255.255, your computer can only communicate with other computers in the same range. An example of when these private addresses would be useful is in a classroom lab where you want to prevent access outside of your network. This operating system feature is called Automatic Private IP Addressing (APIPA). APIPA continually requests an IP address at five-minute intervals from a DHCP server for your computer. To access a DNS server, a computer uses the IP address configured in the DNS settings of the NIC in the computer.
NAT
Since private addresses are not allowed on the Internet, a process is needed for translating private IP addresses into public IP addresses to allow local clients to communicate over the Internet. The process used to convert private IP addresses to public IP addresses is called Network Address Translation (NAT). By using NAT, a router is able to translate many internal IP addresses to the same public address.
A protocol is a set of rules. Internet protocols are sets of rules governing communication within and between computers on a network. Protocol specifications define the format of the messages that are exchanged. A letter sent through the postal system also uses protocols. Part of the protocol specifies the position on the envelope that the delivery address needs to be written. If the delivery address is written in the wrong place, the letter cannot be delivered.
Timing is crucial to network operation. Protocols require messages to arrive within certain time intervals so that computers do not wait indefinitely for messages that might have been lost. Therefore, systems maintain one or more timers during transmission of data. Protocols also initiate alternative actions if the network does not meet the timing rules. Many protocols consist of a suite of other protocols that are stacked in layers. These layers depend on the operation of the other layers in the suite to function properly.
These are the main functions of protocols:
Identifying errors
Compressing the data
Deciding how data is to be sent
Addressing data
Deciding how to announce sent and received data
Although there are many other protocols, Figure 1 summarizes some of the more common protocols used on networks and the Internet.
To understand how networks and the Internet work, you must be familiar with the commonly used protocols. These protocols are used to browse the web, send and receive e-mail, and transfer data files. You will encounter other protocols as your experience in IT grows, but they are not used as often as the common protocols described here.
In Figure 2, click the protocol names to learn more about each one.
The more you understand about each of these protocols, the more you will understand how networks and the Internet work.
Internet Control Message Protocol (ICMP) is used by devices on a network to send control and error messages to computers and servers. There are several different uses for ICMP, such as announcing network errors, announcing network congestion, and troubleshooting.
Packet Internet Groper (Ping) is commonly used to test connections between computers. Ping is a simple but highly useful command line utility used to determine whether a specific IP address is accessible. The command line options that can be used with the ping command are shown in Figure 1.
You can ping the IP address to test IP connectivity. Ping works by sending an ICMP echo request to a destination computer or other network device. The receiving device then sends back an ICMP echo reply message to confirm connectivity. Four ICMP echo requests (pings) are sent to the destination computer. If it is reachable, the destination computer responds with four ICMP echo replies. The percentage of successful replies can help you to determine the reliability and accessibility of the destination computer.
You can also use ping to find the IP address of a host when the name is known. If you ping the name of a website, for example, cisco.com, as shown in Figure 2, the IP address of the server displays.
Other ICMP messages are used to report undelivered packets, data on an IP network that includes source and destination IP addresses, and whether a device is too busy to handle the packet. Data, in the form of a packet, arrives at a router, which is a networking device that forwards data packets across networks toward their destinations. If the router does not know where to send the packet, the router deletes it. The router then sends an ICMP message back to the sending computer informing it that the data was deleted. When a router becomes very busy, it might send a different ICMP message to the sending computer indicating that it should slow down due to congestion on the network.
Many devices can be used in a network to provide connectivity. The device you use depends on how many devices you are connecting, the type of connections that they use, and the speed at which the devices operate. These are the most common devices on a network:
Computers
Hubs
Switches
Routers
Wireless access points
The physical components of a network are needed to move data between these devices. The characteristics of the media determine where and how the components are used. These are the most common media used on networks:
Twisted-pair
Fiber-optic cabling
Radio waves
After completing this section, you will meet these objectives:
Identify names, purposes, and characteristics of network devices.
Identify names, purposes, and characteristics of common network cables.
To make data transmission more extensible and efficient than a simple peer-to-peer network, network designers use specialized network devices, such as hubs, switches, routers, and wireless access points, to send data between devices.
Hubs
Hubs, shown in Figure 1, are devices that extend the range of a network by receiving data on one port, and then regenerating the data and sending it out to all other ports. This process means that all traffic from a device connected to the hub is sent to all the other devices connected to the hub every time the hub transmits data. This causes a great amount of network traffic. Hubs are also called concentrators, because they serve as a central connection point for a LAN.
Bridges and Switches
Files are broken up into small pieces of data, called packets, before they are transmitted over a network. This process allows for error checking and easier retransmission if the packet is lost or corrupted. Address information is added to the beginning and to the end of packets before they are transmitted. The packet, along with the address information, is called a frame.
LANs are often divided into sections called segments, similar to the way a company is divided into departments. The boundaries of segments can be defined using a bridge. A bridge is a device used to filter network traffic between LAN segments. Bridges keep a record of all the devices on each segment to which the bridge is connected. When the bridge receives a frame, the destination address is examined by the bridge to determine if the frame is to be sent to a different segment or dropped. The bridge also helps to improve the flow of data by keeping frames confined to only the segment to which the frame belongs.
Switches, shown in Figure 2, are sometimes called multiport bridges. A typical bridge has two ports, linking two segments of the same network. A switch has several ports, depending on how many network segments are to be linked. A switch is a more sophisticated device than a bridge. A switch maintains a table of the MAC addresses for computers that are connected to each port. When a frame arrives at a port, the switch compares the address information in the frame to its MAC address table. The switch then determines which port to use to forward the frame.
Routers
Whereas a switch connects segments of a network, routers, shown in Figure 3, are devices that connect entire networks to each other. Switches use MAC addresses to forward a frame within a single network. Routers use IP addresses to forward frames to other networks. A router can be a computer with special network software installed, or a router can be a device built by network equipment manufacturers. Routers contain tables of IP addresses along with optimal destination routes to other networks.
Wireless Access Points
Wireless access points, shown in Figure 4, provide network access to wireless devices such as laptops and PDAs. The wireless access point uses radio waves to communicate with radios in computers, PDAs, and other wireless access points. An access point has a limited range of coverage. Large networks require several access points to provide adequate wireless coverage.
Multipurpose Devices
There are network devices that perform more than one function. It is more convenient to purchase and configure one device that serves all of your needs than to purchase a separate device for each function. This is especially true for the home user. In your home, you would purchase a multipurpose device instead of a switch, a router, and a wireless access point. The Linksys 300N, shown in Figure 5, is an example of a multipurpose device.
networks. A wide variety of networking cables are available. Coaxial and twisted-pair cables use copper to transmit data. Fiber-optic cables use glass or plastic to transmit data. These cables differ in bandwidth, size, and cost. You need to know what type of cable to use in different situations to install the correct cables for the job. You also need to be able to troubleshoot and repair problems that you encounter.
Twisted-Pair
Twisted-pair is a type of copper cabling that is used for telephone communications and most Ethernet networks. A pair of wires forms a circuit that can transmit data. The pair is twisted to provide protection against crosstalk, which is the noise generated by adjacent pairs of wires in the cable. Pairs of copper wires are encased in color-coded plastic insulation and twisted together. An outer jacket protects the bundles of twisted pairs.
When electricity flows through a copper wire, a magnetic field is created around the wire. A circuit has two wires, and in a circuit, the two wires have oppositely-charged magnetic fields. When the two wires of the circuit are next to each other, the magnetic fields cancel each other out. This is called the cancellation effect. Without the cancellation effect, your network communications become slow due to the interference caused by the magnetic fields.
There are two basic types of twisted-pair cables:
Unshielded twisted-pair (UTP) – Cable that has two or four pairs of wires. This type of cable relies solely on the cancellation effect produced by the twisted-wire pairs that limits signal degradation caused by electromagnetic interface (EMI) and radio frequency interference (RFI). UTP is the most commonly used cabling in networks. UTP cables have a range of 100 m (328 ft).
Shielded twisted-pair (STP) – Each pair of wires is wrapped in metallic foil to better shield the wires from noise. Four pairs of wires are then wrapped in an overall metallic braid or foil. STP reduces electrical noise from within the cable. It also reduces EMI and RFI from outside the cable.
Although STP prevents interference better than UTP, STP is more expensive because of extra shielding, and more difficult to install because of the thickness. In addition, the metallic shielding must be grounded at both ends. If improperly grounded, the shield acts like an antenna picking up unwanted signals. STP is primarily used outside North America.
Category Rating
UTP comes in several categories that are based on two factors:
Number of wires in the cable
Number of twists in those wires
Category 3 is the wiring used for telephone systems and for Ethernet LAN at 10 Mbps. Category 3 has four pairs of wires. Category 3 telephone cable is usually terminated into an RJ-11 connector.
Category 5 and Category 5e have four pairs of wires with a transmission rate of 100 Mbps. Category 5 and 5e are the most common network cables used. Category 5e has more twists per foot than Category 5 wiring. These extra twists further prevent interference from outside sources and the other wires within the cable.
Some Category 6 cables use a plastic divider to separate the pairs of wires, which prevents interference. The pairs also have more twists than Category 5e cable. A twisted pair cable is shown in Figure 1. Category 5, 5e, and 6 cables terminate into an RJ-45 connector. An RJ-11 telephone connector has six pins and an RJ-45 connector has eight pins, as shown in Figure 2.
Coaxial Cable
Coaxial cable is a copper-cored cable surrounded by a heavy shielding. Coaxial cable is used to connect computers in a network. There are several types of coaxial cable:
Thicknet or 10BASE5 – Coax cable used in networks and operated at 10 Mbps with a maximum length of 500 m (1640.4 ft)
Thinnet 10BASE2 – Coax cable used in networks and operated at 10 Mbps with a maximum length of 185 m (607 ft)
RG-59 – Most commonly used for cable television in the U.S.
RG-6 – Higher quality cable than RG-59, with more bandwidth and less susceptibility to interference
A coaxial cable is shown in Figure 3.
Fiber-Optic Cable
An optical fiber is a glass or plastic conductor that transmits information using light. Fiber-optic cable, shown in Figure 4, has one or more optical fibers enclosed in a sheath or jacket. Because it is made of glass, fiber-optic cable is not affected by EMI or RFI. All signals are converted to light pulses to enter the cable, and converted back into electrical signals when they leave it. This means that fiber-optic cable can deliver signals that are clearer, can go farther, and have greater bandwidth than cable made of copper or other metals.
Fiber-optic cable can reach distances of several miles or kilometers before the signal needs to be regenerated. Fiber-optic cable is usually more expensive to use than copper cable, and the connectors are more costly and harder to assemble. Common connectors for fiber-optic networks are SC, ST, and LC. These three types of fiber-optic connectors are half-duplex, which allows data to flow in only one direction. Therefore, two cables are needed.
These are the two types of glass fiber-optic cable:
Multimode – Cable that has a thicker core than single-mode cable. It is easier to make, can use simpler light sources (LEDs), and works well over distances of a few kilometers or less.
Single-mode – Cable that has a very thin core. It is harder to make, uses lasers as a light source, and can transmit signals dozens of kilometers with ease.
Most of the computers that you work on will be part of a network. Topologies and architectures are building blocks for designing a computer network. While you might not build a computer network, you need to understand how they are designed to work on computers that are part of a network.
There are two types of LAN topologies: physical and logical. A physical topology, shown in Figure 1, is the physical layout of the components on the network. A logical topology, shown in Figure 2, determines how the hosts communicate across a medium, such as a cable or the airwaves. Topologies are commonly represented as network diagrams.
A LAN architecture is built around a topology. A LAN architecture comprises all the components that make up the structure of a communications system. These components include the hardware, software, protocols, and sequence of operations.
After completing this section, you will meet these objectives:
Describe LAN topologies.
Describe LAN architectures.
A physical topology defines the way in which computers, printers, and other devices are connected to a network. A logical topology describes how the hosts access the medium and communicate on the network. The type of topology determines the capabilities of the network, such as ease of setup, speed, and cable lengths.
Physical Topologies
Figure 1 shows the common LAN physical topologies:
Bus
Ring
Star
Hierarchical or extended star
Mesh
Bus Topology
In the bus topology, each computer connects to a common cable. The cable connects one computer to the next, like a bus line going through a city. The cable has a small cap installed at the end, called a terminator. The terminator prevents signals from bouncing back and causing network errors.
Ring Topology
In a ring topology, hosts are connected in a physical ring or circle. Because the ring topology has no beginning or end, the cable does not need to be terminated. A specially-formatted frame, called a token, travels around the ring, stopping at each host. If a host wants to transmit data, the host adds the data and the destination address to the frame. The frame then continues around the ring until the frame stops at the host with the destination address. The destination host takes the data out of the frame.
Star Topology
The star topology has a central connection point, which is normally a device such as a hub, switch, or router. Each host on a network has a cable segment that attaches the host directly to the central connection point. The advantage of a star topology is that it is easy to troubleshoot. Each host is connected to the central device with its own wire. If there is a problem with that cable, only that host is affected. The rest of the network remains operational.
Hierarchical or Extended Star Topology
A hierarchical or extended star topology is a star network with an additional networking device connected to the main networking device. Typically, a network cable connects to one hub, and then several other hubs connect to the first hub. Larger networks, such as those of corporations or universities, use the hierarchical star topology.
Mesh Topology
The mesh topology connects all devices to each other. When every device is connected to every other device, a failure of any cable does not affect the network. The mesh topology is used in WANs that interconnect LANs.
Logical Topologies
The two most common types of logical topologies are broadcast and token passing.
In a broadcast topology, each host addresses either data to a particular host or to all hosts connected on a network. There is no order that the hosts must follow to use the network – it is first come, first served for transmitting data on the network.
Token passing controls network access by passing an electronic token sequentially to each host. When a host receives the token, it can send data on the network. If the host has no data to send, it passes the token to the next host, and the process repeats itself.
LAN architecture describes both the physical and logical topologies used in a network. Figure 1 shows the three most common LAN architectures.
Ethernet
The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network use the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method. In CSMA/CD, hosts access the network using the first come, first served broadcast topology method to transmit data.
Ethernet uses a logical bus or broadcast topology and either a bus or star physical topology. As networks expand, most Ethernet networks are implemented using an extended star or hierarchical star topology. Standard transfer rates are 10 Mbps and 100 Mbps, but new standards outline Gigabit Ethernet, which is capable of attaining speeds up to 1000 Mbps (1 Gbps).
Token Ring
IBM originally developed Token Ring as a reliable network architecture based on the token-passing access control method. Token Ring is often integrated with IBM mainframe systems. Token Ring is used with computers and mainframes.
Token Ring is an example of an architecture in which the physical topology is different from its logical topology. The Token Ring topology is referred to as a star-wired ring because the outer appearance of the network design is a star. The computers connect to a central hub, called a multistation access unit (MSAU). Inside the device, however, the wiring forms a circular data path, creating a logical ring. The logical ring is created by the token traveling out of an MSAU port to a computer. If the computer does not have any data to send, the token is sent back to the MSAU port and then out the next port to the next computer. This process continues for all computers and therefore resembles a physical ring.
FDDI
Fiber distributed data interface (FDDI) is a type of Token Ring network. The implementation and topology of FDDI differs from the IBM Token Ring LAN architecture. FDDI is often used to connect several buildings in an office complex or on a university campus.
FDDI runs on fiber-optic cable. FDDI combines high-speed performance with the advantages of the token-passing ring topology. FDDI runs at 100 Mbps on a dual-ring topology. The outer ring is called the primary ring, and the inner ring is called the secondary ring.
Normally, traffic flows only on the primary ring. If the primary ring fails, the data automatically flows onto the secondary ring in the opposite direction.
An FDDI dual ring supports a maximum of 500 computers per ring. The total distance of each length of the cable ring is 100 km (62 mi). A repeater, which is a device that regenerates signals, is required every 2 km (1.2 mi). In recent years, many Token Ring networks have been replaced by faster Ethernet networks.
Several worldwide standards organizations are responsible for setting networking standards. Standards are used by manufacturers as a basis for developing technology, especially communications and networking technologies. Standardizing technology ensures that the devices you use will be compatible with other devices using the same technology. The standards groups create, examine, and update standards. These standards are applied to the development of technology to meet the demands for higher bandwidth, efficient communication, and reliable service.
Click each of the standards in Figure 1 to learn more information.
Ethernet protocols describe the rules that control how communication occurs on an Ethernet network. To ensure that all Ethernet devices are compatible with each other, the IEEE developed standards for manufacturers and programmers to follow when developing Ethernet devices.
After completing this section, you will meet these objectives:
Explain cabled Ethernet standards.
Explain wireless Ethernet standards.
IEEE 802.3
The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network implement the CSMA/CD access control method.
In CSMA/CD, all end stations "listen" to the network wire for clearance to send data. This process is similar to waiting to hear a dial tone on a phone before dialing a number. When the end station detects that no other host is transmitting, the end station attempts to send data. If no other station sends any data at the same time, this transmission arrives at the destination computer with no problems. If another end station observed the same clear signal and transmitted at the same time, a collision occurs on the network media.
The first station that detects the collision, or the doubling of voltage, sends out a jam signal that tells all stations to stop transmitting and to run a backoff algorithm. A backoff algorithm calculates random times in which the end station will start to try network transmission again. This random time is typically in one or two milliseconds (ms), or thousandths of a second. This sequence occurs every time there is a collision on the network and can reduce Ethernet transmission by up to 40 percent.
Ethernet Technologies
The IEEE 802.3 standard defines several physical implementations that support Ethernet. Some of the common implementations are described here.
Ethernet
10BASE-T is an Ethernet technology that uses a star topology. 10BASE-T is a popular Ethernet architecture whose features are indicated in its name:
The ten (10) represents a speed of 10 Mbps.
BASE represents baseband transmission. In baseband transmission, the entire bandwidth of a cable is used for one type of signal.
The T represents twisted-pair copper cabling.
10BASE-T
There are many advantages to using 10BASE-T:
Installation of cable is inexpensive compared to fiber-optic installation.
Cables are thin, flexible, and easier to install than coaxial cabling.
Equipment and cables are easy to upgrade.
There are also disadvantages to using 10BASE-T:
The maximum length for a 10BASE-T segment is only 100 m (328 ft).
Cables are susceptible to EMI.
Fast Ethernet
The high bandwidth demands of many modern applications, such as live video conferencing and streaming audio, have created a need for higher data-transfer speeds. Many networks require more bandwidth than 10 Mbps Ethernet.
100BASE-TX is much faster than 10BASE-T and has a theoretical bandwidth of 100 Mbps.
100BASE-TX
There are many advantages to using 100BASE-TX:
At 100 Mbps, transfer rates of 100BASE-TX are ten times that of 10BASE-T.
100BASE-X uses twisted-pair cabling, which is inexpensive and easy to install.
There are also disadvantages to using 100BASE-TX:
The maximum length for a 100BASE-TX segment is only 100 m (328 ft).
Cables are susceptible to EMI.
1000BASE -T is commonly known as Gigabit Ethernet. Gigabit Ethernet is a LAN architecture.
1000BASE-T
There are many advantages to using 1000BASE-T:
The 1000BASE-T architecture supports data transfer rates of 1 Gbps. At 1 Gbps, it is ten times faster than Fast Ethernet, and 100 times faster than Ethernet. This increased speed makes it possible to implement bandwidth-intensive applications, such as live video.
The 1000BASE-T architecture has interoperability with 10BASE-T and 100BASE-TX.
There are also disadvantages to using 1000BASE-T:
The maximum length for a 1000BASE-T segment is only 100 m (328 ft).
It is susceptible to interference.
Gigabit NICs and switches are expensive.
Additional equipment is required.
10BASE-FL, 100BASE-FX, 1000BASE-SX, and LX are fiber-optic Ethernet technologies.
IEEE 802.11 is the standard that specifies connectivity for wireless networks. IEEE 802.11, or Wi-Fi, refers to a collective group of standards – 802.11a, 802.11b, 802.11g, and 802.11n. These protocols specify the frequencies, speeds, and other capabilities of the different Wi-Fi standards.
802.11a
Devices conforming to the 802.11a standard allow WLANs to achieve data rates as high as 54 Mbps. IEEE 802.11a devices operate in the 5 GHz radio frequency range and within a maximum range of 45.7 m (150 ft).
802.11b
802.11b operates in the 2.4 GHz frequency range with a maximum theoretical data rate of 11 Mbps. These devices operate within a maximum range of 91 m (300 ft).
802.11g
IEEE 802.11g provides the same theoretical maximum speed as 802.11a, which is 54 Mbps, but operates in the same 2.4 GHz spectrum as 802.11b. Unlike 802.11a, 802.11g is backward-compatible with 802.11b. 802.11g also has a maximum range of 91 m (300 ft).
802.11n
802.11n is a newer wireless standard that has a theoretical bandwidth of 540 Mbps and operates in either the 2.4 GHz or 5 GHz frequency range with a maximum range of 250 m (984 ft).
An architectural model is a common frame of reference for explaining Internet communications and developing communication protocols. It separates the functions of protocols into manageable layers. Each layer performs a specific function in the process of communicating over a network.
The TCP/IP model was created by researchers in the U.S. Department of Defense (DoD). The TCP/IP model is a tool used to help explain the TCP/IP suite of protocols, which is the dominant standard for transporting data across networks. This model has four layers, as shown in Figure 1.
In the early 1980s, the International Standards Organization (ISO) developed the Open Systems Interconnect (OSI) model, which was defined in ISO standard 7498-1, to standardize the way devices communicate on a network. This model has seven layers, as shown in Figure 1. This model was a major step forward toward ensuring that there would be interoperability between network devices.
After completing this section, you will meet these objectives:
Define the TCP/IP model.
Define the OSI model.
Compare OSI and TCP/IP.
The TCP/IP reference model provides a common frame of reference for the development of the protocols used on the Internet. It consists of layers that perform functions necessary to prepare data for transmission over a network. The chart in Figure 1 shows the four layers of the TCP/IP model.
A message begins at the top layer, the Application Layer, and moves down the TCP/IP layers to the bottom layer, the Network Access Layer. Header information is added to the message as it moves down through each layer and is then transmitted. After reaching the destination, the message travels back up through each layer of the TCP/IP model. The header information that was added to the message is stripped away as the message moves up through the layers toward its destination.
Application Layer Protocols
Application Layer protocols provide network services to user applications such as web browsers and e-mail programs. Explore some of the more common Internet protocols in Figure 2, to learn more about the protocols that operate in the Application Layer.
Transport Layer Protocols
Transport Layer protocols provide end-to-end management of the data. One of the functions of these protocols is to divide the data into manageable segments for easier transport across the network. Explore each of the protocols in Figure 3, to learn more about the protocols that operate in the Transport Layer.
Internet Layer Protocols
Internet Layer protocols operate in the third layer from the top in the TCP/IP model. These protocols provide connectivity between hosts in the network. Explore each of the protocols in Figure 4, to learn more about the protocols that operate in the Internet Layer.
Network Access Layer Protocols
Network Access Layer protocols describe the standards that hosts use to access the physical media. The IEEE 802.3 Ethernet standards and technologies, such as CSMA/CD and 10BASE-T, are defined in this layer.
The OSI model is an industry-standard framework that is used to divide network communications into seven distinct layers. Although other models exist, most network vendors today build their products using this framework.
A system that implements protocol behavior consisting of a series of these layers is known as a protocol stack. Protocol stacks can be implemented either in hardware or software, or a combination of both. Typically, only the lower layers are implemented in hardware, and the higher layers are implemented in software.
Each layer is responsible for part of the processing to prepare data for transmission on the network. The chart in Figure 1 shows what each layer of the OSI model does.
In the OSI model, when data is transferred, it is said to virtually travel down the OSI model layers of the sending computer, and up the OSI model layers of the receiving computer.
When a user wants to send data, such as an e-mail, the encapsulation process starts at the Application Layer. The Application Layer is responsible for providing network access to applications. Information flows through the top three layers and is considered to be data when it gets down to the Transport Layer.
At the Transport Layer, the data is broken down into more manageable segments, or Transport Layer protocol data units (PDUs), for orderly transport across the network. A PDU describes data as it moves from one layer of the OSI model to another. The Transport Layer PDU also contains information such as port numbers, sequence numbers, and acknowledgement numbers, which is used for reliable data transport.
At the Network Layer, each segment from the Transport Layer becomes a packet. The packet contains logical addressing and other Layer 3 control information.
At the Data Link Layer, each packet from the Network Layer becomes a frame. The frame contains physical address and error correction information.
At the Physical Layer, the frame becomes bits. These bits are transmitted one at a time across the network medium.
At the receiving computer, the de-encapsulation process reverses the process of encapsulation. The bits arrive at the Physical Layer of the OSI model of the receiving computer. The process of virtually traveling up the OSI model of the receiving computer brings the data to the Application Layer, where an e-mail program displays the e-mail.
NOTE: Mnemonics can help you remember the seven layers of the OSI. Some examples include: "All People Seem To Need Data Processing" and "Please Do Not Throw Sausage Pizza Away".
The OSI model and the TCP/IP model are both reference models used to describe the data communication process. The TCP/IP model is used specifically for the TCP/IP suite of protocols, and the OSI model is used for the development of standard communication for equipment and applications from different vendors.
The TCP/IP model performs the same process as the OSI model, but uses four layers instead of seven. The chart in Figure 1 shows how the layers of the two models compare.
A NIC is required to connect to the Internet. The NIC may come preinstalled, or you might have to purchase one on your own. In rare cases, you might need to update the driver. You can use the driver disc that comes with the motherboard or adapter card, or you can supply a driver that you downloaded from the manufacturer.
After the NIC and the driver have been installed, you can connect the computer to the network.
In addition to installing a NIC, you might also need to install a modem to connect to the Internet.
After completing this section, you will meet these objectives:
Install or update a NIC driver.
Attach the computer to an existing network.
Describe the installation of a modem.
Sometimes a manufacturer publishes new driver software for a NIC. A new driver might enhance the functionality of the NIC, or it might be needed for operating system compatibility.
When installing a new driver, disable virus protection software to ensure that the driver installs correctly. Some virus scanners detect a driver update as a possible virus attack. Install only one driver at a time; otherwise, some updating processes might conflict.
A best practice is to close all applications that are running so that they are not using any files associated with the driver update. Before updating a driver, you should visit the website of the manufacturer. In many cases, you can download a self-extracting executable driver file that automatically installs or updates the driver. Alternatively, you can click the Update Driver button in the toolbar of the Device Manager.
The "+" next to the Network adapters category allows you to expand the category and show the network adapters installed in your system. To view and change the properties of the adapter, or update the driver, expand the category and double-click the specific adapter. In the adapter properties window, select the Driver tab.
Note: Sometimes the driver installation process prompts you to reboot the computer.
Checking wireless adapter properties for Windows XP
Click the network icon in the system tray > Properties > Configure > Advanced, as shown in Figure 1.
Checking wireless adapter properties for Windows Vista
Click the network icon in the system tray > Network and Sharing Center > Manage wireless networks > Adapter properties > if prompted for permission click Continue > Configure > Advanced, as shown in Figure 2.
Uninstall a NIC Driver
If a new NIC driver does not perform as expected after it has been installed, the driver can be uninstalled, or rolled back, to the previous driver. Double-click the adapter in the Device Manager. In the Adapter Properties window, select the Driver tab and click Roll Back Driver. If no driver was installed before the update, this option is not available. In that case, you must find a driver for the device and install it manually if the operating system could not find a suitable driver for the NIC.
Now that the NIC drivers are installed, you are ready to connect to the network. Plug a network cable, also called an Ethernet patch or straight-through cable, into the network port on the computer. Plug the other end into the network device or wall jack.
After connecting the network cable, look at the LEDs, or link lights, next to the Ethernet port on the NIC to see if there is any activity. Figure 1 shows the link lights on a NIC. If there is no activity, this might indicate a faulty cable, a faulty hub port, or even a faulty NIC. You might have to replace one or more of these devices to correct the problem.
After you have confirmed that the computer is connected to the network and the link lights on the NIC indicate a working connection, the computer needs an IP address. Most networks are set up so that the computer receives an IP address automatically from a local DHCP server. If the computer does not have an IP address, you must enter a unique IP address in the TCP/IP properties of the NIC.
Every NIC must be configured with the following information:
Protocols – The same protocol must be implemented between any two computers that communicate on the same network.
IP address – This address is configurable and must be unique to each device. The IP address can be manually configured or automatically assigned by DHCP.
MAC address – Each device has a unique MAC address. The MAC address is assigned by the manufacturer and cannot be changed.
After the computer is connected to the network, test connectivity with the ping command. Use the ipconfig command, shown in Figure 2, to find out what your IP address is. Ping your own IP address to make sure that your NIC is working properly, as shown in Figure 3. After you have determined that your NIC is working, ping your default gateway or another computer on your network. A default gateway allows a host to communicate outside of your network. If you can ping other devices on your own network and your default gateway, you have connectivity and the NIC is working. If any of these pings fail, you need to troubleshoot the network connection, the NIC, and IP address settings.
Telnet, as well as ping and tracert, can be used to verify connectivity. Telnet is a protocol that provides remote access to servers and networking devices. Telnet specifies how to create and terminate a session to a remote computer or device. It also provides the syntax and order of the commands that can be issued during a session. It can be used to make configuration changes to a remote device, such as a router or switch. With the correct permissions, users can start and stop processes, and even shut down the remote device.
To support Telnet client connections, the connected device runs a service called Telnet, as shown in Figure 4. Most operating systems include a Telnet client. On a Microsoft Windows PC, Telnet can be run from the command prompt. Telnet supports user authentication, but it does not support the transport of encrypted data. All data exchanged during a Telnet session is transported as plain text across the network. The data can be intercepted and easily understood, including the username and password used to authenticate the device.
A modem is an electronic device that transfers data between one computer and another using analog signals over a telephone line. Examples of modems are shown in Figure 1. The modem converts digital data to analog signals for transmission. The modem at the receiving end reconverts the analog signals back to digital data to be interpreted by the computer. The process of converting analog signals to digital and back again is called modulation/demodulation. Modem-based transmission is very accurate, despite the fact that telephone lines can be noisy due to clicks, static, and other problems.
An internal modem plugs into an expansion slot on the motherboard. To configure a modem, jumpers might have to be set to select the IRQ and I/O addresses. No configuration is needed for a plug-and-play modem, which can only be installed on a motherboard that supports plug-and-play. A modem using a serial port that is not yet in use must be configured. Additionally, the software drivers that come with the modem must be installed for the modem to work properly. Drivers for modems are installed the same way drivers are installed for NICs.
External modems connect to a computer through the serial and USB ports.
When computers use the public telephone system to communicate, it is called Dialup Networking (DUN). Modems communicate with each other using audio tone signals. This means that modems are able to duplicate the dialing characteristics of a telephone. DUN creates a Point-to-Point Protocol (PPP) connection between two computers over a phone line.
After the line connection has been established, a "handshaking sequence" takes place between the two modems and the computers. The handshaking sequence is a series of short communications that occur between the two systems. This is done to establish the readiness of the two modems and computers to engage in data exchange. Dialup modems send data over the serial telephone line in the form of an analog signal. Because the analog signals change gradually and continuously, they can be drawn as waves. In this system, the digital signals are represented by 1s and 0s. The digital signals must be converted to a waveform to travel across telephone lines. They are converted back to the digital form, 1s and 0s, by the receiving modem so that the receiving computer can process the data.
AT Commands
All modems require software to control the communication session. Most modem software uses the Hayes-compatible command set. The Hayes command set is based on a group of instructions that always begin with a set of attention characters (AT), followed by the command characters. These are known as AT commands. The AT command set is shown in Figure 2.
The AT commands are modem control commands. The AT command set is used to issue dial, hang up, reset, and other instructions to the modem. Most user manuals that come with a modem contain a complete listing of the AT command set.
The standard Hayes-compatible code to dial is ATDxxxxxxx. There are usually no spaces in an AT string. If a space is inserted, most modems ignore it. The "x" signifies the number dialed. There are seven digits for a local call and 11 digits for a long-distance call. A "W" indicates that the modem waits for an outside line, if necessary, to establish a tone before proceeding. Sometimes, a "T" is added to signify tone dialing, or a "P" is added to signify pulse dialing.
There are many ways to connect to the Internet. Phone, cable, satellite, and private telecommunications companies offer Internet connections for businesses and home use.
In the 1990s, the Internet was typically used for data transfer. Transmission speeds were slow compared to the high-speed connections that are available today. Most Internet connections were analog modems that used the "plain old telephone service" (POTS) to send and receive data. In recent years, many businesses and home users have switched to high-speed Internet connections. The additional bandwidth allows for transmission of voice and video as well as data.
You should understand how users connect to the Internet and the advantages and disadvantages of different connection types.
After completing this section, you will meet these objectives:
Describe telephone technologies.
Define power line communication.
Define broadband.
Define VoIP.
Several WAN solutions are available for connecting between sites or to the Internet. WAN connection services provide different speeds and levels of service. Before committing to any type of Internet connection, research all available services to determine the best solution to match the needs of your customer.
Analog Telephone
This technology uses standard voice telephone lines. This type of service uses a modem to place a telephone call to another modem at a remote site, such as an Internet service provider. There are two major disadvantages of using the phone line with an analog modem. The first is that the telephone line cannot be used for voice calls while the modem is in use. The second is the limited bandwidth provided by analog phone service. The maximum bandwidth using an analog modem is 56 Kbps, but in reality, it is usually much lower than that. An analog modem is not a good solution for the demands of busy networks.
Integrated Services Digital Network (ISDN)
The next advancement in WAN service is ISDN. ISDN is a standard for sending voice, video, and data over normal telephone wires. ISDN technology uses the telephone wires as an analog telephone service. However, ISDN uses digital technology to carry the data. Because it uses digital technology, ISDN provides higher quality voice and higher speed data transfer than traditional analog telephone service.
ISDN digital connections offer three services: Basic Rate Interface (BRI), Primary Rate Interface (PRI), and Broadband ISDN (BISDN). ISDN uses two different types of communications channels. The "B" channel carries the information, which might be data, voice, or video. The "D" channel is usually used for controlling and signaling, but can be used for data.
Click the names of the types of ISDN in Figure 1 to learn more.
Digital Subscriber Line (DSL)
DSL is an always-on technology. “Always-on” means that there is no need to dial up each time to connect to the Internet. DSL uses the existing copper telephone lines to provide high-speed digital data communication between end users and telephone companies. Unlike ISDN, where the digital data communications replaces the analog voice communications, DSL shares the telephone wire with analog signals.
The telephone company limits the bandwidth of the analog voice on the lines. This limit allows the DSL to place digital data on the phone wire in the unused portion of the bandwidth. This sharing of the phone wire allows voice calls to be placed while DSL is connecting to the Internet.
There are two major considerations when selecting DSL. DSL has distance limitations. The phone lines used with DSL were designed to carry analog information. Therefore, the length that the digital signal can be sent is limited and cannot pass through any form of multiplexer used with analog phone lines. The other consideration is that the voice information and the data carried by DSL must be separated at the customer site. A device called a splitter separates the connection to the phones and the connection to the local network devices.
Asymmetric Digital Subscriber Line (ADSL)
ADSL is currently the most commonly used DSL technology. ADSL has different bandwidth capabilities in each direction. ADSL has a fast downstream speed – typically 1.5 Mbps. Downstream is the process of transferring data from the server to the end user. This is beneficial to users who are downloading large amounts of data. The high-speed upload rate of ADSL is slower. ADSL does not perform well when hosting a web server or FTP server, both of which involve upload-intensive Internet activities.
Click the types of DSL in Figure 2 to learn more.
Power line communication (PLC) is a communication method that uses power distribution wires (local electric grid) to send and receive data.
PLC is known by other names:
Power Line Networking (PLN)
Mains Communication
Power Line Telecoms (PLT)
With PLC, an electric company can superimpose an analog signal over the standard 50 or 60 Hz AC that travels in power lines. The analog signal can carry voice and data signals.
PLC might be available in areas where other high-speed connections are not. PLC is faster than an analog modem and might cost much less than other high-speed connection types. As this technology matures, it will become more common to find and might increase in speed.
You can use PLC to network computers within your home instead of installing network cabling or wireless technology. PLC connections can be used anywhere there is an electrical outlet. You can control lighting and appliances using PLC without installing control wiring.
Broadband is a technique used to transmit and receive multiple signals using multiple frequencies over one cable. For example, the cable used to bring cable television to your home can carry computer network transmissions at the same time. Because the two transmission types use different frequencies, they do not interfere with each other.
Broadband is a signaling method that uses a wide range of frequencies that can be further divided into channels. In networking, the term broadband describes communication methods that transmit two or more signals at the same time. Sending two or more signals simultaneously increases the rate of transmission. Some common broadband network connections include cable, DSL, ISDN, and satellite. Figure 1 shows equipment used to connect to or transmit broadband signals.
Bluetooth
Bluetooth is a wireless technology that enables devices to communicate over short distances. A Bluetooth device can connect up to seven other Bluetooth devices to create a Wireless Personal Area Network (WPAN). This technical specification is described by the IEEE 802.15.1 standard. Bluetooth devices are capable of handling voice and data. Refer to Figure 2 for common Bluetooth characteristics.
Bluetooth devices are divided into three classifications:
Class 1 has a range of approximately 100 m (330 ft)
Class 2 has a range of approximately 10 m (33 ft)
Class 3 has a range of approximately 1 m (3 ft)
Bluetooth devices operate in the 2.4 to 2.485 GHz radio frequency range, which is in the Industrial, Scientific, and Medical (ISM) band. The Bluetooth standard incorporates Adaptive Frequency Hopping (AFH). AFH allows signals to "hop" around using different frequencies within the Bluetooth range, thereby reducing the chance of interference when multiple Bluetooth devices are present.
Cellular
Cellular technology enables the transfer of voice, video, and data. With a cellular WAN adapter installed, a laptop user can access the Internet over the cellular network. Refer to Figure 3 for a comparison of different cellular WAN characteristics.
Although slower than DSL and cable connections, cellular WANs are still fast enough to be classified as a high-speed connection. Cellular networks use one or more of the following technologies:
Global System for Mobile communications (GSM) – Standard used by the worldwide cellular network
General Packet Radio Service (GPRS) – Data service for users of GSM
Quad-band – Allows a cellular phone to operate on all four GSM frequencies: 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz
Short Message Service (SMS) – Data service used to send and receive text messages
Multimedia Messaging Service (MMS) – Data service used to send and receive text messages and can include multimedia content
Enhanced Data Rates for GSM Evolution (EDGE) – Provides increased data rates and improved data reliability
Evolution-Data Optimized (EV-DO) – Provides fast download rates
High Speed Downlink Packet Access (HSDPA) – Provides enhanced G3 access speed
Cable
A cable modem connects your computer to the cable company using the same coaxial cable that connects to your cable television (CATV). You can plug your computer directly into the cable modem, or you can connect a router, switch, hub, or multipurpose network device so that multiple computers can share the connection to the Internet.
DSL
With DSL, the voice and data signals are carried on different frequencies on the copper telephone wires. A filter is used to prevent DSL signals from interfering with phone signals. Plug the filter into a phone jack, and plug the phone into the filter.
The DSL modem does not require a filter. The DSL modem is not affected by the frequencies of the telephone. Like a cable modem, a DSL modem can connect directly to your computer, or it can be connected to a networking device to share the Internet connection with multiple computers.
ISDN
ISDN is another example of broadband. ISDN uses multiple channels and can carry different types of services; therefore, it is considered a type of broadband. ISDN can carry voice, video, and data.
Satellite
Broadband satellite is an alternative for customers who cannot get cable or DSL connections. A satellite connection does not require a phone line or cable, but uses a satellite dish for two-way communication. Download speeds are typically up to 500 Kbps; uploads are closer to 56 Kbps. It takes time for the signal from the satellite dish to relay to your ISP through the satellite orbiting the Earth.
People who live in rural areas often use satellite broadband because they need a faster connection than dialup, and no other broadband connection is available.
Fiber Broadband
Fiber broadband provides faster connection speeds and bandwidth than cable modems, DSL, or ISDN. Fiber broadband can deliver a multitude of digital information such as telephone, video, data, and advanced features like video conferencing. A single fiber pair can carry millions of phone calls, as compared to a single copper pair, which can carry six phone calls.
VoIP is a method to carry telephone calls over the data networks and Internet. VoIP converts the analog signals of our voices into digital information that is transported in IP packets.
VoIP can also use an existing IP network to provide access to the Public Switched Telephone Network (PSTN). When using VoIP to connect to the PSTN, you might be dependent on an Internet connection. This can be a disadvantage if the Internet connection experiences an interruption in service. When a service interruption occurs, the user cannot make phone calls.
A Virtual Private Network (VPN) is a private network that uses a public network, like the Internet, to connect remote sites or users together. A VPN uses dedicated secure connections routed through the Internet from the company private network to the remote user. When connected to the company private network, users become part of that network and have access to all services and resources as if they were physically connected to the LAN.
Remote-access users must install the VPN client on their computers to form a secure connection with the company private network. The VPN client software encrypts data before sending it over the Internet to the VPN gateway at the company private network. VPN gateways establish, manage, and control VPN connections, also known as VPN tunnels. A basic VPN connection is shown in the figure.
There are common preventive maintenance techniques that should continually be performed for a network to operate properly. In an organization, if there is one malfunctioning computer, generally only one user is affected. But if the network is malfunctioning, many or all users are unable to work.
One of the biggest problems with network devices, especially in the server room, is heat. Network devices, such as computers, hubs, and switches, do not perform well when overheated. Often, excess heat is generated by accumulated dust and dirty air filters. When dust gathers in and on network devices, it impedes the proper flow of cool air and sometimes even clogs fans. It is important to keep network rooms clean and change air filters often. It is also a good idea to have replacement filters available for prompt maintenance.
Preventive maintenance involves checking the various components of a network for wear. Check the condition of network cables because they are often moved, unplugged, and kicked. Many network problems can be traced to a faulty cable. You should replace any cables that have exposed wires, are badly twisted, or are bent.
Label your cables. This practice saves troubleshooting time later. Refer to wiring diagrams, and always follow your company's cable labeling guidelines.
Counterfeiting and the IT Industry
A critical aspect of preventive maintenance that is sometimes overlooked is the issue of counterfeiting. Counterfeit products are often called fakes. They can be hardware, software, and documentation that bear a trademark or logo without the trademark owner’s knowledge or consent. These include products that do not originate from authorized manufacturers or are produced without the approval of a trademark owner.
Counterfeit products are often made with cheaper materials and with little or no quality control, and can cause problems in your network. These products might also have invalid warranty and software licenses, no support entitlement, or incorrect initial settings. In addition, counterfeit equipment often fails health and safety compliance testing. The counterfeit product might be cheaper to buy initially, but might be more expensive to maintain. A counterfeit product can create risk to a network and can even be a potential health and safety hazard.
To minimize the risk of purchasing counterfeit products, it is recommended that customers purchase only from the manufacturer's authorized partners, or directly from the manufacturer. When products are not purchased through authorized channels, the manufacturer cannot guarantee the source, quality or authenticity of those products. When the equipment you are buying is mission critical, quality and authenticity should always be your most important consideration.
Network issues can be simple or complex. To assess how complicated the problem is, you should determine how many computers on the network are experiencing the problem.
If there is a problem with one computer on the network, start the troubleshooting process at that computer. If there is a problem with all computers on the network, start the troubleshooting process in the network room where all computers are connected. As a technician, you should develop a logical and consistent method for diagnosing network problems by eliminating one problem at a time.
Follow the steps outlined in this section to accurately identify, repair, and document the problem. The troubleshooting process is shown in Figure 1.
Counterfeiting is a serious issue in troubleshooting as well as in preventive maintenance. Network problems could be related to counterfeit components. To help ensure that you are getting authentic products, Figure 2 shows the points to consider when placing orders or requesting quotes.
Counterfeit products not only pose network, health and safety risks, but the trafficking in counterfeit networking equipment is also a crime that carries serious penalties. In 2008, a former owner of a computer company was sentenced to 30 months in prison and ordered to pay a large sum in restitution as a result of his conviction for trafficking in counterfeit computer components. This type of case serves as an important reminder to customers about the risk of purchasing outside the manufacturer’s authorized sales and distribution channels.
The cosmetic differences between an authentic networking product and a counterfeit can be extremely subtle. There are also performance differentiators between authentic products and counterfeits. Many manufacturers have teams that are staffed with engineers well-versed in these differentiators.
After completing this section, you will meet these objectives:
Review the troubleshooting process.
Identify common network problems and solutions.
Network problems can result from a combination of hardware, software, and connectivity issues. Computer technicians must be able to analyze the problem and determine the cause of the error to repair the network issue. This process is called troubleshooting.
The first step in the troubleshooting process is to identify the problem. Figure 1 is a list of open-ended and closed-ended questions to ask the customer.
After you have talked to the customer, you can establish a theory of probable causes. Figure 2 is a list of some common probable causes for network problems.
After you have developed some theories about what is wrong, test your theories to determine the cause of the problem. Figure 3 is a list of quick procedures that can determine the exact cause of the problem or even correct the problem. If a quick procedure does correct the problem, you can go to step 5 to verify full system functionality. If a quick procedure does not correct the problem, you might need to research the problem further to establish the exact cause.
After you have determined the exact cause of the problem, establish a plan of action to resolve the problem and implement the solution. Figure 4 shows sources of information to gather additional information to resolve an issue.
After you have corrected the problem, verify full functionality and, if applicable, implement preventive measures. Figure 5 is a list of the steps to verify the solution.
In the final step of the troubleshooting process, you must document your findings, actions and outcomes. Figure 6 is a list of the tasks required to document the problem and the solution.
Network problems can be attributed to hardware, software, connectivity issues, or some combination of the three. You will resolve some types of network problems more often than others. Figure 1 is a chart of common network problems and solutions.
This chapter introduced you to the fundamentals of networking, the benefits of having a network, and the ways to connect computers to a network. The different aspects of troubleshooting a network were discussed with examples of how to analyze and implement simple solutions. The following concepts from this chapter are important to remember:
A computer network is composed of two or more computers that share data and resources.
A LAN refers to a group of interconnected computers that are under the same administrative control.
A WAN is a network that connects LANs in geographically separated locations.
In a peer-to-peer network, devices are connected directly to each other. A peer-to-peer network is easy to install, and no additional equipment or dedicated administrator is required. Users control their own resources, and a network works best with a small number of computers. A client/server network uses a dedicated system that functions as the server. The server responds to requests made by users or clients connected to the network.
A LAN uses a direct connection from one computer to another. It is suitable for a small area, such as in a home, building, or school. A WAN uses point-to-point or point-to-multipoint, serial communications lines to communicate over greater distances. A WLAN uses wireless technology to connect devices together.
The network topology defines the way in which computers, printers, and other devices are connected. Physical topology describes the layout of the wire and devices, as well as the paths used by data transmissions. Logical topology is the path that signals travel from one point to another. Topologies include bus, star, ring, and mesh.
Networking devices are used to connect computers and peripheral devices so that they can communicate. These include hubs, bridges, switches, routers, and multipurpose devices. The type of device implemented depends on the type of network.
Networking media can be defined as the means by which signals, or data, are sent from one computer to another. Signals can be transmitted either by cable or wireless means. The media types discussed were coaxial, twisted-pair, fiber-optic cabling, and radio frequencies.
Ethernet architecture is now the most popular type of LAN architecture. Architecture refers to the overall structure of a computer or communications system. It determines the capabilities and limitations of the system. The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network implement the CSMA/CD access control method.
The OSI reference model is an industry-standard framework that is used to divide the functions of networking into seven distinct layers. These layers include Application, Presentation, Session, Transport, Network, Data Link, and Physical. It is important to understand the purpose of each layer.
The TCP/IP suite of protocols has become the dominant standard for the Internet. TCP/IP represents a set of public standards that specify how packets of information are exchanged between computers over one or more networks.
A NIC is a device that plugs into a motherboard and provides ports for the network cable connections. It is the computer interface with the LAN.
A modem is an electronic device that is used for computer communications through telephone lines. It allows data transfer between one computer and another. The modem converts byte-oriented data to serial bit streams. All modems require software to control the communication session. The set of commands that most modem software uses is known as the Hayes-compatible command set.
The three transmission methods to sending signals over data channels are simplex, half-duplex, and full-duplex. Full-duplex networking technology increases performance because data can be sent and received at the same time. DSL, two-way cable modem, and other broadband technologies operate in full-duplex mode.
Network devices and media, such as computer components, must be maintained. It is important to clean equipment regularly and use a proactive approach to prevent problems. Repair or replace broken equipment to prevent downtime.
When troubleshooting network problems, listen to what your customer tells you so that you can formulate open-ended and closed-ended questions that will help you determine where to begin fixing the problem. Verify obvious issues and try quick solutions before escalating the troubleshooting process.
Chapter 9
Technicians need to understand computer and network security. Failure to implement proper security procedures can have an impact on users, computers, and the general public. Private information, company secrets, financial data, computer equipment, and items of national security are placed at risk if proper security procedures are not followed.
After completing this chapter, you will meet these objectives:
Explain why security is important.
Describe security threats.
Identify security procedures.
Identify common preventive maintenance techniques for security.
Troubleshoot security.
Computer and network security help to keep data and equipment functioning and provide access only to appropriate people. Everyone in an organization should give high priority to security because everyone can be affected by a lapse in security.
Theft, loss, network intrusion, and physical damage are some of the ways a network or computer can be harmed. Damage or loss of equipment can mean a loss of productivity. Repairing and replacing equipment can cost the company time and money. Unauthorized use of a network can expose confidential information and reduce network resources.
An attack that intentionally degrades the performance of a computer or network can also harm the production of an organization. Poorly implemented security measures to wireless network devices demonstrate that physical connectivity is not necessary for unauthorized access by intruders.
The primary responsibilities of a technician include data and network security. A customer or an organization might depend on you to ensure that their data and computer equipment are secure. You might perform tasks that are more sensitive than those assigned to the average employee. You might repair, adjust, and install equipment. You will need to know how to configure settings to keep the network secure but still keep it available to those who need to access it. You must ensure that software patches and updates are applied, anti-virus software is installed, and anti-spyware software is used. You can also be asked to instruct users how to maintain good security practices with
computer equipment.
To successfully protect computers and the network, a technician must understand both types of threats to computer security:
Physical – Events or attacks that steal, damage, or destroy equipment, such as servers, switches, and wiring
Data – Events or attacks that remove, corrupt, deny access, allow access, or steal information
Threats to security can come from the inside or outside of an organization, and the level of potential damage can vary greatly:
Internal – Employees have access to data, equipment, and the network
Malicious threats are when an employee intends to cause damage.
Accidental threats are when the user damages data or equipment unintentionally.
External – Users outside of an organization that do not have authorized access to the network or resources
Unstructured – Attackers use available resources, such as passwords or scripts, to gain access and run programs designed to vandalize.
Structured – Attackers use code to access operating systems and software.
Physical loss or damage to equipment can be expensive, and data loss can be detrimental to your business and reputation. Threats against data are constantly changing as attackers find new ways to gain entry and commit their crimes.
After completing this section, you will meet these objectives:
Define viruses, worms, and Trojans.
Explain web security.
Define adware, spyware, and grayware.
Explain Denial of Service (DoS).
Describe spam and popup windows.
Explain social engineering.
Explain TCP/IP attacks.
Explain hardware deconstruction and recycling.
Computer viruses are deliberately created and sent out by attackers. A virus is attached to small pieces of computer code, software, or documents. The virus executes when the software is run on a computer. If the virus is spread to other computers, those computers could continue to spread the virus.
A virus is a program written with malicious intent and sent out by attackers. The virus is transferred to another computer through e-mail, file transfers, and instant messaging. The virus hides by attaching itself to a file on the computer. When the file is accessed, the virus executes and infects the computer. A virus has the potential to corrupt or even delete files on your computer, use your e-mail to spread itself to other computers, or even erase your entire hard drive.
Some viruses can be exceptionally dangerous. The most damaging type of virus is used to record keystrokes. These viruses can be used by attackers to harvest sensitive information, such as passwords and credit card numbers. Viruses might even alter or destroy information on a computer. Stealth viruses can infect a computer and lay dormant until summoned by the attacker.
A worm is a self-replicating program that is harmful to networks. A worm uses the network to duplicate its code to the hosts on a network, often without any user intervention. It is different from a virus because a worm does not need to attach to a program to infect a host. Even if the worm does not damage data or applications on the hosts it infects, it is harmful to networks because it consumes bandwidth.
A Trojan is technically a worm. The Trojan does not need to be attached to other software. Instead, a Trojan threat is hidden in software that appears to do one thing, and yet behind the scenes it does another. Trojans are often disguised as useful software. The Trojan program can reproduce like a virus and spread to other computers. Computer data damage and production loss could be significant. A technician might be needed to perform the repairs, and employees might lose or have to replace data. An infected computer could be sending critical data to competitors, while at the same time infecting other computers on the network.
Virus protection software, known as anti-virus software, is software designed specifically to detect, disable, and remove viruses, worms, and Trojans before they infect a computer. Anti-virus software becomes outdated quickly, however, and it is the responsibility of the technician to apply the most recent updates, patches, and virus definitions as part of a regular maintenance schedule. Many organizations establish a written security policy stating that employees are not permitted to install any software that is not provided by the company. Organizations also make employees aware of the dangers of opening e-mail attachments that may contain a virus or a worm. Web security is important because so many people visit the World Wide Web every day. Some of the features that make the web useful and entertaining can also make it harmful to a computer.
Tools that are used to make web pages more powerful and versatile, as shown in Figure 1, can also make computers more vulnerable to attacks. These are some examples of web tools:
ActiveX – Technology created by Microsoft to control interactivity on web pages. If ActiveX is on a page, an applet or small program has to be downloaded to gain access to the full functionality.
Java – Programming language that allows applets to run within a web browser. Examples of applets include a calculator or a counter.
JavaScript – Programming language developed to interact with HTML source code to allow interactive websites. Examples include a rotating banner or a popup window.
Attackers might use any of these tools to install a program on a computer. To prevent against these attacks, most browsers have settings that force the computer user to authorize the downloading or use of ActiveX, Java, or JavaScript, as shown in Figure 2.
Adware, spyware, and grayware are usually installed on a computer without the knowledge of the user. These programs collect information stored on the computer, change the computer configuration, or open extra windows on the computer without the user’s consent.
Adware is a software program that displays advertising on your computer. Adware is usually distributed with downloaded software. Most often, adware is displayed in a popup window. Adware popup windows are sometimes difficult to control and will open new windows faster than users can close them.
Grayware or malware is a file or program other then a virus that is potentially harmful. Many grayware attacks are phishing attacks that try to persuade the reader to unknowingly provide attackers with access to personal information. As you fill out an online form, the data is sent to the attacker. Grayware can be removed using spyware and adware removal tools.
Spyware, a type of grayware, is similar to adware. It is distributed without any user intervention or knowledge. Once installed, the spyware monitors activity on the computer. The spyware then sends this information to the organization responsible for launching the spyware.
Phishing is a form of social engineering where the attacker pretends to represent a legitimate outside organization, such as a bank. A potential victim is contacted via e-mail. The attacker might ask for verification of information, such as a password or username, to supposedly prevent some terrible consequence from occurring.
NOTE: There is rarely a need to give out sensitive personal or financial information online. Be suspicious. Use the postal service to share sensitive information.
DoS is a form of attack that prevents users from accessing normal services, such as e-mail and a web server, because the system is busy responding to abnormally large amounts of requests. DoS works by sending enough requests for a system resource that the requested service is overloaded and ceases to operate.
Common DoS attacks include the following:
Ping of death – A series of repeated, larger than normal pings that crash the receiving computer
E-mail bomb – A large quantity of bulk e-mail that overwhelms the e-mail server preventing users from accessing it
Distributed DoS (DDoS) is another form of attack that uses many infected computers, called zombies, to launch an attack. With DDoS, the intent is to obstruct or overwhelm access to the targeted server. Zombie computers located at different geographical locations make it difficult to trace the origin of the attack. Spam, also known as junk mail, is unsolicited e-mail, as shown in Figure 1. In most cases, spam is used as a method of advertising. However, spam can be used to send harmful links or deceptive content, as shown in Figure 2.
When used as an attack method, spam can include links to an infected website or an attachment that could infect a computer. These links or attachments can result in lots of windows designed to capture your attention and lead you to advertising sites. These windows are called popups. As shown in Figure 2, uncontrolled popup windows can quickly cover the user's screen and prevent any work from getting done.
Many anti-virus and e-mail software programs automatically detect and remove spam from an e-mail inbox. Some spam still might get through, so look for some of the more common indications:
No subject line
Incomplete return address
Computer generated e-mail
Return e-mail not sent by the user
A social engineer is a person who is able to gain access to equipment or a network by tricking people into providing the necessary access information. Often, the social engineer gains the confidence of an employee and convinces the employee to divulge username and password information.
A social engineer might pose as a technician to try to gain entry into a facility, as shown in Figure 1. When inside, the social engineer might look over shoulders to gather information, seek out papers on desks with passwords and phone extensions, or obtain a company directory with e-mail addresses.
Here are some basic precautions to help protect against social engineering:
Never give out your password.
Always ask for the ID of unknown persons.
Restrict access of unexpected visitors.
Escort all visitors.
Never post your password in your work area.
Lock your computer when you leave your desk.
Do not let anyone follow you through a door that requires an access card.
TCP/IP is the protocol suite that is used to control all of the communications on the Internet. Unfortunately, TCP/IP can also make a network vulnerable to attackers.
Some of the most common attacks:
SYN flood – Randomly opens TCP ports, tying up the network equipment or computer with a large amount of false requests, causing sessions to be denied to others
DoS – Sends abnormally large amounts of requests to a system preventing access to the services
DDoS – Uses "zombies" to make tracing the origin of the DoS attack difficult to locate
Spoofing – Gains access to resources on devices by pretending to be a trusted computer
Man-in-the-middle – Intercepts or inserts false information in traffic between two hosts
Replay – Uses network sniffers to extract usernames and passwords to be used at a later date to gain access
DNS poisoning – Changes the DNS records on a system to point to false servers where the data is recorded
Hardware destruction is the process of removing sensitive data from hardware and software before recycling or discarding. Hard drives should be fully erased to prevent the possibility of recovery using specialized software. Three methods are commonly used to either destroy or recycle data and hard drives:
Data wiping
Hard drive destruction
Hard drive recycling
Data Wiping
Data wiping, also known as secure erase, is a procedure performed to permanently delete data from a hard drive. Data wiping is often performed on hard drives containing sensitive data such as financial information. It is not enough to delete files or even format the drive. Use a third-party tool to overwrite data multiple times, rendering the data unusable. It is important to remember that data wiping is irreversible, and the data can never be recovered.
Hard Drive Destruction
Companies with sensitive data should always establish clear policies for hard drive disposal. It is important to be aware that formatting and reinstalling an operating system on a computer does not ensure that information cannot be recovered. Destroying the hard drive is the best option for companies with sensitive data. To fully ensure that data cannot be recovered from a hard drive, you should carefully shatter the platters with a hammer and safely dispose of the pieces.
Other storage media, such as CDs and floppy disks, must also be destroyed. Use a shredding machine that is designed to destroy this type of media.
Hard Drive Recycling
Hard drives that do not contain sensitive data should be reused in other computers. The drive can be reformatted, and a new operating system can be installed. If the drive is not needed, it can be sold or donated.
A security plan should be used to determine what will be done in a critical situation. Security plan policies should be constantly updated to reflect the latest threats to a network. A security plan with clear security procedures is the basis for a technician to follow. Security plans should be reviewed on a yearly basis.
Part of the process of ensuring security is to conduct tests to determine areas where security is weak. Testing should be done on a regular basis. New threats are released daily. Regular testing provides details of any possible weaknesses in the current security plan that should be addressed.
There are multiple layers of security in a network, including physical, wireless, and data. Each layer is subject to security attacks. The technician needs to understand how to implement security procedures to protect equipment and data.
After completing this section, you will meet these objectives:
Explain what is required in a basic local security policy.
Explain the tasks required to protect physical equipment.
Describe ways to protect data.
Describe wireless security techniques.
A security policy should describe how a company addresses security issues, as shown in Figure 1. Though local security policies may vary between organizations, there are questions all organizations should ask:
What assets require protection?
What are the possible threats?
What to do in the event of a security breach?
When creating a security policy, some key areas to observe are shown in Figure 2. The scope of the policy and the consequences of non-compliance should be clearly described. Security policies should be reviewed regularly and updated as necessary. You should keep a revision history to track all policy changes. Security is the responsibility of every person within the company. All employees, including non-computer users, must be trained to understand the security policy and notified of any security policy updates.
Password guidelines are an important component of a security policy. Passwords should be required to have a minimum length and include uppercase and lowercase letters combined with numbers and symbols. It is common for a security policy to require users to change their passwords on a regular basis and govern the number of password attempts before an account is temporarily locked out.
You should also define employee access to data in a security policy. The policy should protect highly sensitive data from public access, while ensuring employees can still perform their job tasks. Data can be classified from public to top secret, and can have several different levels between them. Public information can be seen by anyone and has no security requirements. Public information cannot be used maliciously to hurt a company or an individual. However, top secret information needs the most security, because the data exposure can be extremely detrimental to a government, a company, or an individual.
Physical security is as important as data security. When a computer is taken, the data is also stolen.
There are several methods of physically protecting computer equipment, as shown in Figures 1 and 2:
Control access to facilities.
Use cable locks with equipment.
Keep telecommunication rooms locked.
Fit equipment with security screws.
Use security cages around equipment.
Label and install sensors, such as Radio Frequency Identification (RFID) tags, on equipment.
Install physical alarms triggered by motion-detection sensors.
Use webcams with motion-detection and surveillance software.
For access to facilities, there are several means of protection:
Card keys that store user data, including level of access
Biometric sensors that identify physical characteristics of the user, such as fingerprints or retinas
Posted security guard
Sensors, such as RFID tags, to monitor equipment
One form of hardware security is the Trusted Platform Module (TPM). The TPM is a specialized chip installed on the motherboard of a computer to be used for hardware and software authentication. The TPM stores information specific to the host system, such as encryption keys, digital certificates, and passwords. Applications that use encryption can make use of the TPM chip to secure things like user authentication information, software license protection, and encrypted files, folders, and disks. Integrating hardware security, such as TPM with software security, results in a much safer computer system than using software security alone.
The value of physical equipment is often far less than the value of the data it contains. The loss of sensitive data to a company's competitors or to criminals can be costly. Such losses can result in a lack of confidence in the company and the dismissal of computer technicians in charge of computer security. To protect data, several methods of security protection can be implemented.
Password Protection
Password protection can prevent unauthorized access to content, as shown in Figure 1. Attackers can gain access to unprotected computer data. All computers should be password protected. Two levels of password protection are recommended:
BIOS – Prevents the operating system from booting, and prevents BIOS settings from being changed without the appropriate password
Login – Prevents unauthorized access to the local computer and the network
Network logins provide a means of logging activity on the network and either preventing or allowing access to resources. This makes it possible to determine which resources are being accessed. Usually, the system administrator defines a naming convention for the usernames when creating network logins. A common example of a username is the first initial of the person's first name and then the entire last name. You should keep the username naming convention simple so that people do not have a hard time remembering it. Usernames, like passwords, are an important piece of information and should not be revealed. Default usernames should be changed so that hackers do not know either part of the username and password combination.
When assigning passwords, the level of password control should match the level of protection required. A good security policy should be strictly enforced and include, but not be limited to, the following rules:
Passwords should expire after a specific period of time.
Passwords should contain a mixture of letters and numbers so that they cannot easily be broken.
Password standards should prevent users from writing down passwords and exposing them to public view.
Rules about password expiration and lockout should be defined. Lockout rules apply when an unsuccessful attempt has been made to access the system or when a specific change has been detected in the system configuration.
To simplify the process of administrating security, it is common to assign users to groups, and then to assign groups to resources. This allows the access capability of users on a network to be changed easily by assigning or removing the user from various groups. This is useful when setting up temporary accounts for visiting workers or consultants, giving you the ability to limit access to resources.
To prevent unauthorized users from accessing local computers and network resources, lock your workstation, laptop, or server when you are not present.
Data Encryption
Encrypting data uses codes and ciphers. Traffic between resources and computers on the network can be protected from attackers monitoring or recording transactions by implementing encryption. It might not be possible to decipher captured data in time to make any use of it.
A VPN uses encryption to protect data. A VPN connection allows remote users to safely access resources as if their computer is physically attached to the local network.
Software Firewall
Data being transported on a network is called traffic. A software firewall is a program that runs on a computer to allow or deny traffic between the computer and the network to which it is connected. Every communication using TCP/IP is associated with a port number. HTTPS, for instance, uses port 443 by default. A software firewall, as shown in Figure 2, is capable of protecting a computer from intrusion through the ports. The user can control the type of data sent to a computer by selecting which ports will be open and which will be secured. You must create exceptions to allow certain traffic or applications to connect to the computer. Firewalls can block incoming and outgoing network connections unless exceptions are defined to open and close the ports required by a program.
Data Backups
Data backup procedures should be included in a security plan. Data can be lost or damaged in circumstances such as theft, equipment failure, or a disaster such as a fire or flood. Backing up data is one of the most effective ways of protecting against data loss. Here are some considerations for data backups:
Frequency of backups – Backups can take a long time. Sometimes it is easier to make a full backup monthly or weekly, and then do frequent partial backups of any data that has changed since the last full backup. However, spreading the backups over many recordings increases the amount of time needed to restore the data.
Storage of backups – Backups should be transported to an approved offsite storage location for extra security. The current backup media is transported to the offsite location on a daily, weekly, or monthly rotation, as required by the local organization.
Security of backups – Backups can be protected with passwords. These passwords would have to be entered before the data on the backup media could be restored.
Smart Card Security
A smart card is a small plastic card, about the size of a credit card, with a small chip embedded in it. The chip is an intelligent data carrier, capable of processing, storing, and safeguarding thousands of bytes of data. Smart cards store private information such as bank account numbers, personal identification, medical records, and digital signatures. Smart cards provide authentication and encryption to keep data safe.
Biometric Security
Biometric security compares physical characteristics against stored profiles to authenticate people. A profile is a data file containing known characteristics of an individual such as a fingerprint or a handprint. In theory, biometric security is more secure than security measures such as passwords or smart cards, because passwords can be discovered and smart cards can be stolen. Common biometric devices available include fingerprint readers, handprint readers, iris scanners, and face recognition devices.
Figure 3 shows biometric devices and smart cards.
File System Security
All file systems keep track of resources, but only file systems with journals can log access by user, date, and time. A comparison of the two file systems is shown in Figure 4. The FAT32 file system, which is used in some versions of Windows, lacks both journaling and encryption capabilities. As a result, situations that require good security are usually deployed using a file system such as NTFS, which is part of Windows 2000 and Windows XP. If increased security is needed, it is possible to run certain utilities, such as CONVERT, to upgrade a FAT32 file system to NTFS. The conversion process is not reversible. It is important to clearly define your goals before making the transition.
Because traffic flows through radio waves in wireless networks, it is easy for attackers to monitor and attack data without having to physically connect to a network. Attackers gain access to a network by being within range of an unprotected wireless network. A technician needs to know how to configure access points and wireless NICs to an appropriate level of security.
When installing wireless services, you should apply wireless security techniques immediately to prevent unwanted access to the network, as shown in Figure 1. Wireless access points should be configured with basic security settings that are compatible with the existing network security. The following items are basic security settings that can be configured on a wireless router or access point:
Service Set Identifier (SSID) – The name of the wireless network. A wireless router or access point broadcasts the SSID by default so that wireless devices can detect the wireless network. Manually enter the SSID on wireless devices to connect to the wireless network when the SSID broadcast has been disabled on the wireless router or access point.
MAC Address Filtering – A technique used to deploy device-level security on a wireless LAN. Because every wireless device has a unique MAC address, wireless routers and access points can prevent wireless devices from connecting to the wireless network if the devices do not have authorized MAC addresses. Enable MAC address filtering, and list each wireless device MAC address to enforce MAC address filtering.
An attacker can access data as it travels over the radio signal. A wireless encryption system can be used to prevent unwanted capture and use of data by encoding the information that is sent. Both ends of every link must use the same encryption standard. The following items are wireless encryption and authentication technologies:
Wired Equivalent Privacy (WEP) – The first generation security standard for wireless. Attackers quickly discovered that WEP encryption was easy to break. The encryption keys used to encode the messages could be detected by monitoring programs. Once the keys were obtained, messages could be easily decoded.
Wi-Fi Protected Access (WPA) – An improved version of WEP. It was created as a temporary solution until the 802.11i (a security layer for wireless systems) was fully implemented. Now that 802.11i has been ratified, WPA2 has been released. It covers the entire 802.11i standard. WPA uses much stronger encryption than WEP encryption.
Wi-Fi Protected Access 2 (WPA2) – An improved version of WPA. This protocol was released to introduce higher levels of security than WPA. WPA2 supports robust encryption providing government grade security. WPA2 can be enabled in two versions: Personal (password authentication) and Enterprise (server authentication).
Lightweight Extensible Authentication Protocol (LEAP), also called EAP-Cisco – A wireless security protocol created by Cisco to address the weaknesses in WEP and WPA. LEAP is a good choice when using Cisco equipment in conjunction with operating systems like Windows and Linux.
Wireless Transport Layer Security (WTLS) is a security layer used in mobile devices that employ the Wireless Applications Protocol (WAP). Mobile devices do not have a great deal of spare bandwidth to devote to security protocols. WTLS was designed to provide security for WAP devices in a bandwidth-efficient manner.
Security strategies are constantly changing, as are the technologies used to secure equipment and data. New exploits are discovered daily. Attackers are constantly searching for new methods to use in an attack. Software manufacturers have to regularly create and issue new patches to fix flaws and vulnerabilities in products. If a computer is left unprotected by a technician, an attacker can easily gain access. Unprotected computers on the Internet can become infected within a few minutes.
Because of the constantly changing security threats, technicians should understand how to install patches and updates. They should also be able to recognize when new updates and patches are available. Some manufacturers release updates on the same day every month, but also send out critical updates when necessary. Other manufacturers provide automatic update services that patch the software every time the computer is turned on, or e-mail notifications when a new patch or update is released.
After completing this section, you will meet these objectives:
Explain how to update signature files for anti-virus and anti-spyware software.
Explain how to install operating system service packs and security patches.
Threats to security from viruses and worms are always present. Attackers constantly look for new ways to infiltrate computers and networks. Because new viruses are always being developed, security software must be continually updated. This process can be performed automatically, but a technician should know how to manually update any type of protection software and all customer application programs.
Click on each step in the figure for more information.
Virus, spyware, and adware detection programs look for patterns in the programming code of the software in a computer. These patterns are determined by analyzing viruses that are intercepted on the Internet and on LANs. These code patterns are called signatures. The publishers of protection software compile the signatures into virus definition tables. To update signature files for anti-virus and spyware software, first check to see if the signature files are the most recent files. This can be done by navigating to the About option of the protection software, or by launching the update tool for the protection software. If the signature files are out of date, update them manually with the Update Now option on most protection software.
You should always retrieve the signature files from the manufacturer’s website to make sure the update is authentic and not corrupted by viruses. This can put great demand on the manufacturer's website, especially when new viruses are released. To avoid creating too much traffic at a single website, some manufacturers distribute their signature files for download to multiple download sites. These download sites are called mirrors.
CAUTION: When downloading the signature files from a mirror, ensure that the mirror site is a legitimate site. Always link to the mirror site from the manufacturer's website.
Viruses and worms can be difficult to remove from a computer. Software tools are required to remove viruses and repair the computer code that the virus has modified. These software tools are provided by operating system manufacturers and security software companies. Make sure that you download these tools from a legitimate site.
Patches are code updates that manufacturers provide to prevent a newly discovered virus or worm from making a successful attack. From time to time, manufacturers combine patches and upgrades into a comprehensive update application called a service pack. Many infamous and devastating virus attacks could have been much less severe if more users had downloaded and installed the latest service pack.
The Windows operating system routinely checks the Windows Update website for high-priority updates that can help protect a computer from the latest security threat. These updates can include security updates, critical updates, and service packs. Depending on the setting you choose, Windows automatically downloads and installs any high-priority updates that your computer needs, or notifies you as these updates become available.
Updates must be installed, not just downloaded. If you use the Automatic setting, you can schedule the time and day. Otherwise, new updates are installed at 3 a.m. by default. If your computer is turned off during a scheduled update, updates are installed the next time you start your computer. You can also choose to have Windows notify you when a new update is available and install the update yourself.
Follow the steps in Figure 1 to update the operating system with a service pack or security patch.
The troubleshooting process is used to help resolve security issues. These problems range from simple, such as preventing someone from watching over your shoulder, to more complex problems, such as manually removing infected files. Use the troubleshooting steps as a guideline to help you diagnose and repair problems.
After completing this section, you will meet these objectives:
Review the troubleshooting process.
Identify common problems and solutions.
Computer technicians must be able to analyze a security threat and determine the appropriate method to protect assets and repair damage. This process is called troubleshooting.
The first step in the troubleshooting process is to identify the problem. Figure 1 is a list of open-ended and closed-ended questions to ask the customer.
After you have talked to the customer, you can establish a theory of probable causes. Figure 2 is a list of some common probable causes for security problems.
After you have developed some theories about what is wrong, test your theories to determine the cause of the problem. Figure 3 is a list of quick procedures that can determine the exact cause of the problem or even correct the problem. If a quick procedure does correct the problem, you can go to step 5 to verify full system functionality. If a quick procedure does not correct the problem, you might need to research the problem further to establish the exact cause.
After you have determined the exact cause of the problem, establish a plan of action to resolve the problem and implement the solution. Figure 4 shows sources of information to gather additional information to resolve an issue.
After you have corrected the problem, verify full functionality and, if applicable, implement preventive measures. Figure 5 is a list of the steps to verify the solution.
In the final step of the troubleshooting process, you must document your findings, actions, and outcomes. Figure 6 is a list of the tasks required to document the problem and the solution.
Computer problems can be attributed to hardware, software, connectivity issues, or some combination of the three. You will resolve some types of computer problems more often than others. Figure 1 is a chart of common security problems and solutions.
The worksheet is designed to reinforce your communication skills to verify information from the customer.
This chapter discussed computer security and why it is important to protect computer equipment, networks, and data. Threats, procedures, and preventive maintenance relating to data and physical security were described to help you keep computer equipment and data safe. Security protects computers, network equipment, and data from loss and physical danger. The following are some of the important concepts to remember from this chapter:
Security threats can come from inside or outside of an organization.
Viruses and worms are common threats that attack data.
Develop and maintain a security plan to protect both data and physical equipment from loss.
Keep operating systems and applications up to date and secure with patches and service packs.
Chapter 10
What is the relationship between communication skills and troubleshooting? As a computer technician, you will not only fix computers but will also interact with people. In fact, troubleshooting is as much about communicating with the customer as it is about knowing how to fix a computer. In this chapter, you will learn to use good communication skills as confidently as you use a screwdriver.
After completing this chapter, you will meet these objectives:
Explain the relationship between communication and troubleshooting.
Describe good communication skills and professional behavior.
Explain ethics and legal aspects of working with computer technology.
Describe the call center environment and technician responsibilities.
Think of a time when you had to call a repair person to get something fixed. Did it feel like an emergency to you? Did you appreciate it when the repair person was sympathetic and responsive? Perhaps you had a bad experience with a repair person. Are you likely to call that same person to fix a problem again?
Good communication skills enhance a technician's troubleshooting skills. Both of these skill sets take time and experience to develop well. As your hardware, software, and OS knowledge increases, your ability to quickly determine a problem and find a solution will improve. The same principle applies to developing communication skills. The more you practice good communication skills, the more effective you will become when working with customers. A knowledgeable technician who uses good communication skills will always be in demand in the job market.
To troubleshoot a computer, you need to learn the details of the problem from the customer. Most people who need a computer problem fixed are probably feeling some stress. If you establish a good rapport with the customer, the customer might relax a bit. A relaxed customer is more likely to be able to provide the information that you need to determine the source of the problem and then fix it.
Speaking directly with the customer is usually the first step in resolving the computer problem. As a technician, you also have access to several communication and research tools. All of these resources can be used to help gather information for the troubleshooting process.
important to communicate well and to represent yourself professionally. Your professionalism and good communication skills enhance your creditability with the customer.
Your body language can be seen by your customer. A customer can hear your sighs and sense that you are sneering, even over the phone. Conversely, customers can also sense that you are smiling when you are speaking with them on the phone. Many call-center technicians use a mirror at their desk to monitor their facial expressions.
Successful technicians control their own reactions and emotions from one customer call to the next. A good rule for all technicians to follow is that a new customer call means a fresh start. Never carry your frustration from one call to the next.
After completing this section, you will meet these objectives:
Determine the computer problem of the customer.
Display professional behavior with the customer.
Focus the customer on the problem during the call.
Use proper Netiquette.
Implement time and stress management techniques.
Observe Service Level Agreements (SLAs).
Follow business policies.
One of the first tasks of the technician is to determine the type of computer problem that the customer is experiencing.
Remember these three rules at the beginning of your conversation:
Know – Call your customer by name.
Relate – Use brief communication to create a one-to-one connection between you and your customer.
Understand – Determine the customer's level of knowledge about the computer to know how to effectively communicate with the customer.
To accomplish this, practice active listening skills. Allow the customer to tell the whole story. During the time that the customer is explaining the problem, occasionally interject some small word or phrase, such as "I understand", "Yes", "I see", or "Okay". This behavior lets the customer know that you are there and that you are listening.
However, a technician should not interrupt the customer to ask a question or make a statement. This is rude, disrespectful, and creates tension. Many times in a conversation, you might find yourself thinking of what to say before the other person finishes talking. When you do this, you are not really listening. Instead, try listening carefully when other people speak, and let them finish their thoughts.
After you have listened to the customer explain the whole problem, clarify what the customer has said. This helps convince the customer that you have heard and understand the situation. A good practice for clarification is to paraphrase the customer's explanation by beginning with the words "Let me see if I understand what you have told me…". This is a very effective tool that shows the customer that you have listened and that you are concerned with the issues.
After you have assured the customer that you understand the problem, you will probably have to ask some follow-up questions. Make sure that these questions are pertinent. Do not ask questions that the customer has already answered while describing the problem. Doing this only irritates the customer and shows that you were not listening.
Follow-up questions should be targeted, closed-ended questions based on the information that you have already gathered. Closed-ended questions should focus on obtaining specific information. The customer should be able to answer with a simple "yes" or "no" or with a factual response such as, "Windows XP Pro". Use all of the information that you have gathered from the customer to continue filling out the work order.
When dealing with customers, it is necessary to be professional in all aspects of your role. You must handle customers with respect and prompt attention. When on a telephone, make sure that you know how to place a customer on hold, as well as how to transfer a customer without losing the call. It is important how you conduct the call, and your job is to help the customer focus on and communicate the problem so that you can solve it.
Be positive when communicating with the customer. Tell the customer what you can do. Do not focus on what you cannot do. Be prepared to explain alternative ways that you can help them, such as e-mailing information, faxing step-by-step instructions, or using remote control software to solve the problem. Customers will quickly sense whether you are interested in helping them.
Figure 1 outlines the process to follow before you put a customer on hold. First, let the customer finish speaking. Then, explain that you have to put the customer on hold, and ask the customer for permission to do so. When the customer agrees to be put on hold, thank the customer. Tell your customer that you will be away only a few minutes and explain what you will be doing during that time.
Figure 2 outlines the process for transferring a call. Follow the same process for a call transfer as you would when placing a customer on hold. Let the customer finish talking and then explain that you have to transfer the call. When the customer agrees to be transferred, tell the customer the phone number that you are transferring the customer to. You should also tell the new technician your name, the name of the customer that you are transferring, and the related ticket number.
When dealing with customers, it is sometimes easier to explain what you should not do. Observe the following list of things that you should not do when communicating with a customer:
Avoid minimizing customer problems.
Avoid using jargon, abbreviations, acronyms, and slang.
Avoid a negative attitude or tone of voice.
Avoid arguing with customers or becoming defensive.
Avoid culturally insensitive remarks.
Avoid being judgmental, insulting, or calling the customer names.
Avoid distractions or interruptions when talking with customers.
Avoid taking personal calls when talking with customers.
Avoid talking to co-workers about unrelated subjects when talking with the customer.
Avoid unnecessary holds and abrupt holds.
Avoid transfers without explaining the purpose of the transfer and getting customer consent.
Avoid negative remarks about other technicians to the customer.
Part of your job is to focus the customer during the phone call. When you focus the customer on the problem, it allows you to control the call. This makes the best use of your time and the customer's time on troubleshooting the problem. Do not take any comments personally, and do not retaliate with any comments or criticism. If you stay calm with the customer, finding a solution to the problem will remain the focal point of the call.
Just as there are many different computer problems, there are many different types of customers, as shown in Figure 1. The list of problem-customer types below is not comprehensive and often a customer can display a combination of traits. Try to recognize which traits your customer exhibits. Recognizing these traits can help you manage the call accordingly.
Talkative Customer
A talkative customer discusses everything except the problem on the call. The customer often uses the call as an opportunity to socialize. It can be difficult to get a talkative customer to focus on the problem.
Rude Customer
A rude customer complains during the call and often makes negative comments about the product, the service, and the technician. This type of customer is sometimes abusive and uncooperative and gets aggravated very easily.
Angry Customer
An angry customer talks loudly during the call and often tries to speak when the technician is talking. Angry customers are usually frustrated that they have a problem and upset that they have to call somebody to fix it.
Knowledgeable Customer
A knowledgeable customer wants to speak with a technician that is equally experienced in computers. This type of customer usually tries to control the call and does not want to speak with a level-one technician.
Inexperienced Customer
An inexperienced customer has difficulty describing the problem. These customers are usually not able to follow directions correctly and not able to communicate the errors that they encounter.
Have you read a blog where two or three members have stopped discussing the issue and are simply insulting each other? These are called "flame wars" and they occur in blogs and e-mail threads. Have you ever wondered if they would actually say those things to each other in person? Perhaps you have received an e-mail that had no greeting or was written entirely in capital letters. How did this make you feel while you were reading it?
As a technician, you should be professional in all communications with customers. For e-mail and text communications, there is a set of personal and business etiquette rules called Netiquette.
In addition to the e-mail and text Netiquette, there are general rules that apply to all of your online interactions with customers and coworkers:
Remember that you are dealing with people.
Adhere to the same standards of behavior that you follow in real life.
Know where you are in cyberspace.
Respect other people's time and bandwidth.
Share expert knowledge.
Do not engage in "flame wars" online.
Respect other people's privacy.
Be forgiving of other people's mistakes.
The list above is not comprehensive. What other general rules about online communications can you think of?
As a technician, you are a very busy person. It is important for your own well-being to use proper time and stress management techniques.
Workstation Ergonomics
The ergonomics of your work area can help you do your job or make it more difficult. Because you spend a major portion of your day at your workstation, make sure that the desk layout works well, as shown in Figure 1. Have your headset and phone in a position that is both easy to reach and easy to use. Your chair should be adjusted to a height that is comfortable. Adjust your computer screen to a comfortable angle so that you do not have to tilt your head up or down to see it. Make sure your keyboard and mouse are also in a position that is comfortable for you. You should not have to bend your wrist to type. If possible, try to minimize external distractions such as noise.
Time Management
For time management, it is important to prioritize your activities. Make sure that you carefully follow the business policy of your company. The company policy might state that you must take "down" calls first, even though they might be harder to solve. A "down" call usually means that a server is not working and the entire office or company is waiting for the problem to be resolved to resume business.
If you have to call back a customer, make sure that you do it as close to the callback time as possible. Keep a list of callback customers and check them off one at a time as you complete these calls. Doing this ensures that you do not forget a customer.
When working with many customers, do not give favorite customers faster or better service. When reviewing the call boards, do not take only the easy customer calls. See Figure 2 for a sample customer call board. Do not take the call of another technician, unless you have permission to do so.
Stress Management
For stress management, take a moment to compose yourself between customer calls. Every call should be independent of each other, and you should not carry any frustrations from one call to the next.
You might have to do some physical activity to relieve stress. You should stand up and take a short walk. Do a few simple stretch movements or squeeze a tension ball. Take a break if you can, and try to relax. You will then be ready to answer the next customer call effectively.
Figure 3 shows ways to relax. Can you think of any other appropriate activities that might relieve stress at work?
When dealing with customers, it is important to adhere to that customer's SLA. An SLA is a contract that defines expectations between an organization and the service vendor to provide an agreed upon level of support. As an employee of the service company, your job is to honor the SLA that you have with the customer. Take a closer look at some of the standard sections found in an SLA by moving over the circles in Figure 1.
An SLA is typically a legal agreement that contains the responsibilities and liabilities of all parties involved. Some of the contents of an SLA usually include the following:
Response time guarantees (often based on type of call and level of service agreement)
Equipment and software that is supported
Where service is provided
Preventive maintenance
Diagnostics
Part availability (equivalent parts)
Cost and penalties
Time of service availability (for example, 24x7; Monday to Friday, 8 a.m. to 5 p.m. EST; and so on)
There might be exceptions to the SLA. Make sure to follow your company business rules in detail. Some of the exceptions might include the ability of the customer to upgrade the level of service, or to escalate to management for review. Escalation to management should be reserved for special situations. For example, a long-standing customer or a customer from a very large company might have a problem that falls outside the parameters stated in their SLA. In these cases, your management might choose to support the customer for customer-relation reasons.
Can you think of any other circumstances in which it might be a good idea to escalate a call to management?
As a technician, you should be aware of all business policies related to customer calls. You would not want to make a promise to a customer that you cannot keep. You should also have a good understanding of all rules governing employees.
Customer Call Rules
The following rules are examples of the specific rules a call center might have to handle customer calls:
Maximum time on call (example: 15 minutes)
Maximum call time in queue (example: three minutes)
Number of calls per day (example: minimum of 30)
Passing calls on to other technicians (example: only when absolutely necessary and not without that technician's permission)
What you can and cannot promise to the customer (see that customer's SLA for details)
When to follow SLA and when to escalate to management
Call Center Employee Rules
There are also other rules to cover general daily activities of employees:
Arrive at your workstation on time and early enough to become prepared, usually about 15 to 20 minutes before the first call.
Do not exceed the allowed number and length of breaks.
Do not take a break or go to lunch if there is a call on the board.
Do not take a break or go to lunch at the same time as other technicians (stagger breaks among technicians).
Do not leave an ongoing call to take a break, go to lunch, or go to a personal appointment.
Make sure that another technician is available if you have to leave.
Contact the customer if you are going to be late for an appointment.
If no other technician is available, check with the customer to see if you can call back later, possibly in the morning.
Do not show favoritism to certain customers.
Do not take another technician's calls without permission.
Do not talk negatively about the capabilities of another technician.
Customer Satisfaction
The following rules should be followed by all employees to ensure customer satisfaction:
Set and meet a reasonable timeline for the call or appointment and communicate this to the customer.
Communicate service expectations to the customer as early as possible.
Communicate the repair status with the customer, including explanations for any delays.
Offer different repair or replacement options to the customer, if applicable.
Give the customer proper documentation on all services provided.
Follow up with the customer at a later date to verify satisfaction.
When you are working with customers and their equipment, there are some general ethical customs and legal rules that you should observe. Often, these customs and rules overlap.
Ethical Customs
You should always have respect for your customers, as well as for their property. Property includes any information or data that might be accessible. Such information or data includes any of the following items:
E-mails
Phone lists
Records or data on the computer
Hard copies of files, information, or data left on desk
Before accessing a computer account, including the administrator account, you should get the permission of the customer. From the troubleshooting process, you might have gathered some private information, such as usernames and passwords. If you document this type of private information, you must keep it confidential. Divulging any customer information to anyone else is not only unethical, but might be illegal. Legal details of customer information are usually covered under the SLA.
Do not send unsolicited messages to a customer. Do not send unsolicited mass mailings or chain letters to customers. Never send forged or anonymous e-mails. All of these activities are considered unethical and, in certain circumstances, might be considered illegal.
Legal Rules
Several computer-related activities are not only unethical but are illegal. Be aware that this is not an exhaustive list:
Do not make any changes to system software or hardware configurations without customer permission.
Do not access a customer's or co-worker's accounts, private files, or e-mail messages without permission.
Do not install, copy, or share digital content (including software, music, text, images, and video) in violation of copyright and software agreements or applicable federal and state law.
Do not use a customer's company IT resources for commercial purposes.
Do not make a customer's IT resources available to unauthorized users.
Keep sensitive customer information confidential.
Do not knowingly use a customer's company resources for illegal activities. Criminal or illegal use includes obscenity, child pornography, threats, harassment, copyright infringement, university trademark infringement, defamation, theft, identity theft, and unauthorized access.
Do you know the copyright and trademark laws in your state or country?
A call center environment is usually very professional and fast-paced. It is a help desk system where customers call in and are placed on a callboard. Available technicians take the customer calls. A technician must supply the level of support that is outlined in the customer's SLA.
After completing this section, you will meet these objectives:
Describe the call center environment.
Describe level-one technician responsibilities.
Describe level-two technician responsibilities.
A call center might exist within a company and offer service to the employees of that company as well as to the customers of that company's products. Alternatively, a call center might be an independent business that sells computer support as a service to outside customers. In either case, a call center is a busy, fast-paced work environment, often operating 24 hours a day.
Call centers tend to have a large number of cubicles. As shown in Figure 1, each cubicle has a chair, at least one computer, a phone, and a headset. The technicians working at these cubicles have varied levels of experience in computers, and some have specialties in certain types of computers, software, or operating systems.
All of the computers in a call center have help desk software. The technicians use this software to manage many of their job functions. Figure 2 shows some of the features of help desk software.
Your call center will have its own business policies regarding call priority. Figure 3 provides a sample chart of how calls can be named, defined, and prioritized.
Call centers sometimes have different names for level-one technicians. These technicians might be known as level-one analysts, dispatchers, or incident screeners. Regardless of the title, the level-one technician's responsibilities are fairly similar from one call center to the next.
The primary responsibility of a level-one technician is to gather pertinent information from the customer. The technician has to document all information in the ticket or work order. The information that the level-one technician must obtain is shown in Figure 1.
Some problems are very simple to resolve, and a level-one technician can usually take care of these without escalating the work order to a level-two technician.
Often, a problem requires the expertise of a level-two technician. In these cases, the level-one technician must be able to translate a customer's problem description into a succinct sentence or two that is entered into the work order. This translation is important so that other technicians can quickly understand the situation without having to ask the customer the same questions again. Figure 2 shows how a customer might describe some of the most common problems and how a technician should document those problems.
As with level-one technicians, call centers sometimes have different names for level-two technicians. These technicians might be known as product specialists or technical-support personnel. The level-two technician's responsibilities are generally the same from one call center to the next.
The level-two technician is usually more knowledgeable than the level-one technician about technology, or has been working for the company for a longer period of time. When a problem cannot be resolved within ten minutes, the level-one technician prepares an escalated work order, as shown in Figure 1. The level-two technician receives the escalated work order with the description of the problem. They then call the customer back to ask any additional questions and resolve the problem.
The following list of guidelines details when to escalate a problem to a more experienced technician. These are generic guidelines. You should follow your company's business policy for problem escalation.
Escalate problems that require opening the computer case.
Escalate problems that require installation of applications, operating systems, or drivers.
Escalate problems that will take a long time to walk a customer through - like CMOS changes.
Escalate down calls. The entire network is down, and a more experienced technician might be able to resolve the issue faster.
Problems that require opening up the computer needs a level-two technician. Level-two technicians can also use remote diagnostic software to connect to the customer's computer to update drivers and software, access the operating system, check the BIOS, and gather other diagnostic information to solve the problem.
In this chapter, you learned about the relationship between communication skills and troubleshooting skills. You have learned that these two skills need to be combined to make you a successful technician. You also learned about the legal aspects and ethics of dealing with computer technology and the property of the customer.
The following concepts from this chapter are important to remember:
To be a successful technician, you must practice good communication skills with customers and co-workers. These skills are as important as technical expertise.
You should always conduct yourself in a professional manner with your customers and co-workers. Professional behavior increases customer confidence and enhances your credibility. You should also learn to recognize the classic signs of a difficult customer and learn what to do and what not to do when you are on a call with this customer.
There are a few techniques that you can use to keep a difficult customer focused on the problem during a call. Primarily, you must remain calm and ask pertinent questions in an appropriate fashion. These techniques keep you in control of the call.
There is a right way and a wrong way to put a customer on hold, or transfer a customer to another technician. Learn and use the right way every time. Doing either of these operations incorrectly can cause serious damage to your company's relationship with its customers.
Netiquette is a list of rules to use whenever you communicate through e-mail, text messaging, instant messaging, or blogs. This is another area where doing things the wrong way can cause damage to your company's relationship with its customers.
You must understand and comply with your customer's SLA. If the problem falls outside the parameters of the SLA, you need to find positive ways of telling the customer what you can do to help, and not what you cannot do. In special circumstances, you might decide to escalate the work order to management.
In addition to the SLA, you must follow the business policies of the company. These policies include how your company prioritizes calls, how and when to escalate a call to management, and when you are allowed to take breaks and lunch.
A computer technician's job is stressful. You rarely meet a customer who is having a good day. You can alleviate some of the stress by setting up your workstation in the most ergonomically beneficial way possible. You should practice time and stress management techniques every day.
There are ethical and legal aspects of working in computer technology. You should be aware of your company's policies and practices. In addition, you might need to familiarize yourself with your state or country's trademark and copyright laws.
The call center is a fast-paced environment. Level-one technicians and level-two technicians each have specific responsibilities. These responsibilities might vary slightly from one call center to another.