Study Guide

JJ

adapter card

-0-

AGP

a

case

JJ

expansion slot

i

floppy disk drive

h

hard drive

k

modem

n

monitor

c

motherboard

m

optical drive

r

PCI

b

power supply

o

printer

e

RAM

d

ROM

CPU

J-

chipset

JJ

The computer is built around an integrated circuit called the processor (also known as microprocessor and central processing unit [CPU]). It is considered the "brain" of the computer because all the instructions it performs are mathematical calculations and logical comparisons. The processor is the central component of the computer. It is plugged into a large circuit board called the motherboard (sometimes referred to as system board).

Vocabulary Exercise: Completion

Fill in the blanks with the appropriate terms about processors. Pentium II and older Pentium III processors plug into a Slot 1. Later Pentium III processors connect using a 370-pin connector.

Early Pentium 4 processors use a 423-pin connector. Newer Pentium 4 processors use a 478-pin connector.

Socket T, also known as a LGA775, is Intel's socket used by today's modern Intel processors.

Socket A is used for AMD processors ranging from the AMD Athlon K7 to the AMD Athlon XP 3200+, and AMD budget processors. It uses a 462-pin connector.

Socket AM2, produced by AMD, has 940 contacts

MMX technology consists of 57 instructions that improve the performance of multimedia tasks.

Hyper-Threading Technology, used in newer Intel processors, allows the processor to act like two processors (logical processors) so that it can utilize the processor resources more efficiently and improve performance. Hyper-Threading can be enabled or disabled in the system BIOS program.

To keep a processor cool, it must use a heat sink (with thermal paste or tape) and fan or some other cooling system.

Some motherboards with dual processor sockets require having a special terminator or voltage regulator module (VRM) in the empty processor slot or socket when both processors are not installed.

Motherboards

The motherboard allows the processor to branch out and communicate with all the computer components. It can be considered the nervous system of the PC.

Motherboards are often described by their form factors (physical dimensions, sizes, and layout). Older motherboards are based on the Baby AT. Newer form factors include ATX (including mini-ATX, Micro-ATX, and Flex-ATX), NXL, and BTX. Different from the Baby AT form factor, the ATX motherboards have the expansion slots parallel to the short side of the board, which allows more space for other components. The processor and RAM are next to the power supply so that heat generated by the CPU and RAM are immediately drawn out of the casing to reduce the amount of heat trapped inside the casing. In addition, the processor and memory modules can be replaced or upgraded without removing any of the expansion cards.

The BTX form factor is designed to balance size, performance, features, and cost. To improve heat dissipation and acoustics, the board has been redesigned to improve airflow through the system;

moving the processor to the "front" of the case allows it to be right next to the intake fan, giving it the coolest air of any component in the system. The airflow is also channeled over the chipset, graphics card, and memory chips.

Read-only memory (ROM) chips contain instructions and data that the processor accesses directly. Unlike the contents of the RAM, the contents of the ROM are permanent. They cannot be changed or erased by normal means and are maintained when power is off.

ROM chips (including flash memory) are used within the PC to provide instructions and data to the processor. The chips and software (programs and data) that have been written onto these chips are called firmware.

The ROM chip contains the basic input/output system (BIOS) that provides instructions and data to the processor. BIOS is the built-in software that determines what a computer can do without accessing programs from a disk. Therefore, you can think of these ROM chips as the instincts of the computer. They contain all the code required to control the boot process, and they control many hardware devices, including the keyboard, display, screen, disk drives, serial communications, and others.

The system BIOS, which is located on the motherboard, directs the boot up and allows basic control of the majority of the hardware. The BIOS chips are typically made from flash memory, which is computer memory that can be electrically erased and reprogrammed, typically by a flash program. Updating the system ROM BIOS (also known as flashing the BIOS) can correct a wide range of problems and will allow the system to work with components that did not exist at the time the motherboard was manufactured.

The motherboard configuration is stored in the complementary metal-oxide-semiconductor (CMOS) memory. Like normal RAM, if the CMOS memory loses power, the content of the CMOS memory is lost. Therefore, the CMOS memory and a real-time clock (to keep track of the date and time) are powered by a CMOS battery.

One essential, yet inexpensive, part of the PC is the motherboard chipset. A chipset consists of the chips and other components on the motherboard that allow different PC components, including the processor, to communicate with each other. It consists of the bus controllers, peripheral controllers, memory controllers, cache controllers, clocks, and timers. The chipset used in a motherboard design greatly influences the performance and limitations of the PC. It defines how much RAM a motherboard can use and what type of RAM chips it will accommodate, as well as cache size, processor types and speed, and the types of expansion slots.

Most of Intel's earlier chipsets and many non-Intel chipsets are broken into a multi-tiered architecture incorporating North and South Bridge components.

Intel's newer chipsets are based on the Intel Hub Architecture (IHA). Like the older chipsets, IHA has two parts: the graphics and AGP memory controller hub (GMCH) and the I/O controller hub (ICH). The GMCH communicates with the processor over the system bus and acts as a controller for memory and AGP. It sometimes comes with integrated video. Unlike the North Bridge, the GMCH does not come with a PCI controller. ICH provides a connection to a PCI bus, ATA disk interface, a USB controller, and the firmware hub. The firmware hub stores system and video BIOS and includes a hardware-based random number generator.

When working within a PC, you must be able to identify the different parts of the motherboard, including the processor, expansion slots, drive connectors, and power connectors. You should also be able to look at the layout to determine its form factor.

Concept Questions

Answer the following questions about motherboards: Describe what the North Bridge component holds.

The North Bridge holds the high-speed components, including the memory controller, AGP controller, and PCI controller.

Describe what the South Bridge component holds.

The South Bridge handles most other forms of I/O (low-speed components) including the PCI peripherals, the ISA bus, floppy drives, hard drives, USB, keyboard and IO devices (parallel port, and serial port and PS/2 ports).

Identify the following in Figure 1-1:

■ Expansion slots

■ Memory sockets

■ Drive connectors

■ Power connector

Figure 1-1 Motherboard Components

Ports

Figure 1-1 Motherboard Components

Ports

RAM is the computer's short-term memory. Program instructions and data are stored on the RAM chips, which the processor accesses directly. The more RAM you have, the more instructions and data you can load. The amount of RAM greatly affects the performance of the PC. However, if power is discontinued to the RAM, as when you shut off your PC, the contents of the RAM disappear. This is why disks are used for long-term storage.

Vocabulary Exercise: Completion

Fill in the blanks with the appropriate terms about RAM. RAM stands for random-access memory. Insufficient RAM can cause the computer to run slower.

RAM chips are volatile, meaning that they immediately lose their data when the computer is shut off.

PC100 SDRAM operates at 100 MHz and requires 10 ns DRAM chips, but requires 8 ns DRAM chips that are capable of running at 125 MHz.

PC133 SDRAM operates at 133 MHz and requires 7.5 ns DRAM chips.

The DDR in DDR DRAM is short for double data rate. DDR chips that run at 400 MHz are known as PC3200. DDR chips that run at 677 MHz are known as PC5300.

SIMM is short for single in-line memory module.

DIMM is short for dual in-line memory module.

RIMM is short for rambus in-line memory module.

72-pin SIMMs are 32 bits wide and can be installed singularly.

DIMM supports 64-bit pathways, whereas RIMM is the only memory module that is 16-bits wide. DIMMs are available in 168-pin and 184-pin sticks.

DDR DIMMS use 184-pin connectors, whereas DDR2 DIMMS use 240-pin connectors. RIMM is available in 184-pin version.

VRAM and SGRAM is a specialized memory used on video cards.

Ports

A port is an interface on a computer to which you can connect a device. Most ports are located at the back of the computer. Some ports are physically part of the motherboard or are connected directly to the motherboard, whereas other ports are physically part of or connected directly to expansion cards. To identify the capabilities of the system and to identify an expansion card, you will need to identify the port by sight.

PC 99 is a specification for PCs jointly developed by Microsoft and Intel in 1998. Its aim was to encourage the standardization of PC hardware to aid Windows compatibility. The PC 99 specification set out the color code for the various standard types of plugs and connectors used on PCs. Because many of the connectors look very similar, particular to a novice PC user, the color scheme made it far easier for people to connect peripherals to the correct ports on a PC. This color code was gradually adopted by almost all PC, motherboard, and peripheral manufacturers.

Serial ports and parallel ports are traditional ports found on PCs, and newer ports that offer more functionality include USB and IEEE 1394 (FireWire). As a PC technician, you need to know the characteristics of these ports.

Identify Ports and Connectors

In the following table, identify the port, the type of connector, and its purpose.

Game Port Female DB-9 Used to connect joysticks to the computer.

It can also be identified as a MIDI port.

PS/2 Mouse Port or PS/2 Keyboard Port mini-DIN 6

Used to connect a mouse.

VGA Port Female DB-15 Used to connect VGA and Super

VGA monitors to the computer.

S-Video Port mini-DIN 4 Used for an analog video signal that connects to TVs, VCRs and video cameras.

SCSI Port 50-pin Used to connect SCSI printers,

Centronics CD ROMs, scanners, and hard drives.

SCSI Port VHDCI Used to connect external SCSI

connector printers, CD-ROMs, scanners, and hard drives.

Mian

DVI Interface DVI-I socket Used to connect digital display devices.

Ethernet Port RJ-45 Typically used to connect to an

Connector Ethernet network cable.

Phone Jack RJ-11 Used to connect to the telephone

Modem Port Connector and the telephone cable.

Universal Type A Used to connect PC peripherals,

Serial Bus USB port including mice, keyboards,

(USB) Port printers, modems, and external disk drives.

Identify the colors typically used for the following ports:

■ Keyboard: Purple

■ Parallel Port: Pink

■ Digital Monitor: White

Identify the following as serial port or parallel port:

■ Also known as IEEE 1284: Parallel Port

■ Also known as RS-232: Serial Port

■ Connects external peripheral devices such as modems and mice: Serial Port

■ Maximum length of cable is 10 feet (3 m): Parallel Port

■ Maximum length of cable is 50 feet (15.2 m): Serial Port

■ Transmits data, multiple bits at a time: Parallel Port

■ Transmits data, one bit at a time: Serial Port

■ Used primarily to connect printers: Parallel Port Identify the following as USB 1.1, USB 2.0, or IEEE 1394:

■ Also known as FireWire: IEEE 1394

■ The maximum data transfer rate speed is 12 Mbps: USB 1.1

■ The maximum data transfer rate speed of is 480 Mbps: USB 2.0

■ Has a data transfer rate of 400 Mbps and supports up to 63 devices: IEEE 1394

■ Supports up to 127 devices: USB 1.1/USB 2.0

Expansion Slots and Boards

The expansion slot, also known as the input/output (I/O) bus, extends the reach of the processor so it can communicate with peripheral devices. Expansion slots are so named because they allow the system to be expanded by the insertion of circuit boards, called expansion cards (also known as daughter boards). They are essential to the computer because a basic system cannot satisfy everyone's needs, and they allow the system to use new technology as it becomes available. Expansion slots consist of connectors and metal traces that carry signals from the expansion card to the rest of the computer, specifically the RAM and processor. These connections are used for power, data, addressing, and control lines.

Throughout the years, several types of expansion slots have been developed. The original IBM PC used the 8-bit PC slot, and the IBM AT used the 16-bit ISA slot. Today's desktop computers include PCI slots and their derivatives (AGP, PCI-X, and PCI Express). As a PC technician, you will need to know the commonly used expansion slots and their characteristics.

Vocabulary Exercise: Completion

Fill in the blanks with the appropriate terms about expansion slots.

PCI is short for Peripheral Component Interconnect. PCI runs at either 33 MHz or 66 MHz.

AGP is short for Accelerated Graphics Port. AGP is made exclusively for video cards.

The original specification for AGP (AGPxl) has a clock speed of 66 MHz and has a maximum bandwidth of 266 Mbps.

AGPx2 has a clock speed of 133 MHz and has a maximum bandwidth of 533 Mbps.

AGPx4 has a clock speed of 266 MHz and has a maximum bandwidth of 1.07 Gbps.

AGPx8 has a clock speed of 533 MHz and has a maximum bandwidth of 2.1 Gbps.

PCI Express is a much faster interface to replace PCI, PCI-X, and AGP interfaces for computer expansion cards and graphics cards.

Whereas PCI, PCI-X, and AGP are based on a parallel interface, PCI Express is based on a serial interface.

Cases

The case of the PC is a metal or plastic box designed to hold and protect the motherboard, the drives, and the power supplies. Like motherboards and processors, cases come in many configurations, which are characterized by the orientation of the box, the number of drives and expansion slots it can hold, and the size of the expansion cards it can take. The computer case should be durable, easy to service, and have enough room for expansion.

Concept Questions

Answer the following question about cases:

List and describe the factors in choosing the computer case:

■ Model type: Desktop (lays flat) versus tower (stands up).

■ Size: Case should have enough space for installed components.

■ Available space: Desktop cases allow space conservation in tight spaces whereas tower can be located under desk.

■ Amount of devices: More devices need more power, which also requires a larger power supply.

■ Power supply: Must match the power rating and connection type.

■ Environment conditions: If you work in a dusty environment, you need to choose a case that reduces the amount of dust that enters the system.

Power Supplies

Electricity is the blood of the computer and comes through the power supply. The power supply converts AC into clean DC power. Like cases and motherboards, power supplies come in many sizes and shapes. The most common are the Baby AT power supplies and ATX power supplies.

Power supplies are rated in what unit? Watts

In the United States, what voltage does the power supply run on? 120 volts

Hard Drive

Disks are half-electronic, half-mechanical devices that store magnetic fields on rotating platters. The magnetic fields represent the data. They are considered long-term storage devices because they do not "forget" their information when power is disconnected. They are also considered the primary mass storage system because they hold all the programs and data files that are fed into RAM. Hard drives are sometimes referred to as fixed disks because they are usually not removed from the PC easily, like a floppy disk or optical disk. This term does not describe all hard drives because there are external hard drives (disks that rest outside of the case) and removable hard drives.

Hard drives communicate with the rest of the computer by means of a cable connected to a controller card or interface, which is either an expansion card or built in to the motherboard. All hard drives consist of the following components: rotating platters, read/write heads, and head actuators.

Today, the common hard drive types include integrated drive electronics (usually referred to as IDE) and small computer system interface (usually referred to as SCSI; pronounced "skuzzy"). IDE hard drives follow the AT attachment (ATA) specification, which has been expanded throughout the years. The SCSI interface, typically found on high-end computers and servers, supports multiple devices in and out of the computer.

Concept Questions

Answer the following question about hard drives: Define the following hard drive terms:

■ Disk platters: Magnetic circular disks made of aluminum, glass, or ceramic material that rotate around a spindle.

■ Read/write heads: Component that reads the data from a platter or writes the data to a platter.

■ Head actuators: The component that moves the read/write heads back and forth.

■ Spindle: The component that the disk platters rotate around.

Vocabulary Exercise: Completion

Fill in the blanks with the appropriate terms about hard drives.

The most popular hard drive interface is IDE. There are two main types of IDE interfaces. They are parallel ATA and serial ATA. Of the two main types of IDE interfaces, serial ATA is faster than parallel ATA. The parallel ATA interface uses a 40-pin ribbon cable. The serial ATA interface uses a two-cable connector (a 7-pin data connector and a 15-pin power connector).

The transfer rate of parallel ATA is up to 133 Mbps. The transfer rate of serial ATA begin at 150 Mbps. The SCSI interface is used for high-end computers.

The older SCSI-1 interfaces supported up to seven SCSI devices (eight if you include the host adapter), whereas newer SCSI interfaces, including Wide SCSI, support up to 15 devices (16 if you include the host adapter).

Different from the IDE interface, the two ends of the SCSI chain must be terminated. Each SCSI device, including the adapter/controller card, is numbered with a SCSI ID number from 0 to 7 or 0 to 15. Narrow SCSI cables use 50-pin connectors, whereas wide SCSI uses 68-pin connectors. Ultra SCSI interfaces can have a maximum cable length of 12 meters. Although traditional SCSI interfaces used a single-ended (SE) signaling method, most SCSI devices use the low voltage differential (LVD) signaling method.

Video Systems

The video system includes the monitor and the video card/adapter. The monitor is a device similar to a television, which is the computer's main output device.

Video Graphics Array (VGA) is an analog computer display standard that has been technologically outdated in the PC market for some time. However, VGA (with a resolution of 640x480 and 16 colors) was the most recent graphical standard that the majority of manufacturers conformed to, making it the lowest common denominator that all PC graphics hardware supports before a device-specific driver is loaded into the computer. For example, the Microsoft Windows splash screen appears while the machine is still operating in VGA mode, which is the reason that this screen always appears in reduced resolution and color depth. Today, computers use a higher resolution and more colors.

The number of pixels (colored dots) that can be displayed on the screen at one time is called the resolution of the screen. The resolution consists of two numbers, the number of pixels going from left to right and the number of pixels going from top to bottom. When you use a higher resolution, you will need additional video memory for the video system to store the additional pixels and more processing by the computer.

Color depth, or bit depth, is the amount of information that determines the color of a pixel. The more colors each pixel can show, the more colors the screen can show and the more shades of the same color, which can produce a more realistic, detailed picture. However, the higher number of bits required to give each pixel a higher color depth requires more video memory for the video system to store the pixel's information and more processing by the computer.

Vocabulary Exercise: Matching

Match the definition on the left with a term on the right.

Definitions a. Distance between the dots.

b. How often per second the image is rebuilt, measured in hertz.

c. High-definition multimedia interface.

d. Made primarily for consumer market: CAMCORDERS, VCRs, DVD.

e. Analog signal that offers excellent quality.

f. An analog computer display standard that offers a resolution of 640x480 and 16 colors.

g. The number of pixels that can be displayed on the screen at one time, usually expressed as the number of dots going across and down the screen.

h. The dots used in a display to generate text, lines, and pictures.

i. The amount of information that determines the color of a pixel.

j. Older type of monitor that tends to be heavy and bulky.

k. A thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector.

l. Connector/interface that usually passes digital video signals.

Terms g resolution

CRT dot pitch HDMI _ LCD _ refresh rate _ pixel _ RGB _ S-video color depth VGA DVI

Concept Questions

Answer the following question about video systems. Complete the following table:

Study Questions

Choose the best answer for each of the questions that follow.

1. Which of the following SCSI interfaces allow up to 16 devices, including the adapter, to be connected on a single shared cable? (Choose all that apply.)

A. Ultra Wide SCSI

B. Fast SCSI

C. Ultra SCSI

D. Fast Wide SCSI

E. Ultra2 Wide SCSI

F. Ultra 2 SCSI

2. The part that moves the read/write heads back and forth within a hard drive or optical drive is called what?

A. Stepper motor

B. Spindle

C. Head actuator

D. Magnetic coupler

3. When you purchase a power supply, the output power supply is measured in which units?

A. Ohms

B. Watts

C. Hertz

D. Mbps

E. Amps

4. Which of the following must be installed in pairs?

A. 72-pin SIMMs

B. 168-pin DIMMs

C. 184-pin DIMMs

D. 184-pin RIMMs

5. You have a 3-row, 15-pin female connector on an expansion card. What kind of expansion card is it?

A. EGA display adapter

B. Serial port adapter

C. VGA display adapter

D. Game port adapter

E. Modem adapter

6. What is the SCSI ID number commonly assigned to the boot device in a PC?

B. 15

7. When you upgrade the BIOS, you are_.

A. Replacing the BIOS

B. Flashing the BIOS

C. Replacing the CMOS chip

D. Resetting the CMOS settings

8. Which of the following has 184 pins and is 16 bits wide?

A. SIMMs

B. DIMMs

C. RIMMs

D. SODIMMs

9. Which two of the following describe the number of pins normally associated with dual in-line memory modules (DIMMs)?

A. 30

B. 72

C. 144

D. 168

E. 184

10. Which of the following is 64 bits wide? (Select all that apply.)

A. 72-pin SIMM

B. 168-pin DIMM

C. 184-pin DIMM

D. 184-pin RIM

11. The size of the monitor is measured in_.

A. Inches diagonally across the screen

B. Square inches of the screen

C. Dots going across and dots going down

D. Pounds

12. Which of the following produces an image that has a resolution of 640x480 and 16 colors?

A. EGA

B. VGA

C. Super VGA

D. Ultra Super VGA

13. If the display adapter is set to 8-bit color, how many colors can it show at one time?

A. 256 colors

B. 65,536 colors

C. 16 million colors

D. 4 billion colors

14. Which is the latest type of printer interface?

A. Serial

B. DVI

C. USB

D. Parallel