Chapter 2 - Computer Hardware

Pointing stick

A mouse-substitute input device that looks like the tip of an eraser embedded in the keyboard of a notebook computer. 89

Ink jet printer

A non-impact printer that creates characters or graphics by spraying liquid ink onto paper or other media. 92

Home computer system

A personal computer designed for use with mainstream computer applications such as Web browsing, e-mail, music downloads, and productivity software. 60

USB flash drive

A portable solid state storage device nicknamed "pen drive" or "keychain drive" that plugs directly into a computer's USB port. 84

PostScript

A printer language, developed by Adobe Systems, which uses a special set of commands to control page layout, fonts, and graphics. 94

Dot matrix printer

A printer that creates characters and graphics by striking an inked ribbon with small wires called "pins," generating a fine pattern of dots. 92

Duplex printer

A printer that prints on both sides of the paper in a single pass. 93

Laser printer

A printer that uses laser-based technology, similar to that used by photocopiers, to produce text and graphics. 92

Floppy disk

A removable magnetic storage medium, typically 3.5" in size, with a capacity of 1.44 MB. 80

Netbook

A scaled-down version of a standard clamshell-style notebook computer. Sometimes called a minilaptop. 59

Benchmarks

A set of tests used to measure computer hardware or software performance. 69

ROM BIOS

A small set of basic input/output system instructions stored in ROM. 73

Notebook computer

A small, lightweight, portable computer that usually runs on batteries. Sometimes called a laptop. 59

Tablet computer

A small, portable computer with a touch-sensitive screen that can be used as a writing or drawing pad. 59

Expansion port

A socket into which the user plugs a cable from a peripheral device, allowing data to pass between the computer and the peripheral device. 95

Expansion slot

A socket or "slot" on a PC motherboard designed to hold a circuit board called an expansion card. 95

Power surge

A spike in electrical voltage that has the potential to damage electronic equipment such as computers. 99

Printer Control Language

A standard for formatting codes embedded within a document that specify how a printer should format each page. 94

Magnetic storage

A technology for recording data onto disks or tape by magnetizing particles of an oxide-based surface coating. 78

Pipelining

A technology that allows a processor to begin executing an instruction before completing the previous instruction. 69

Solid state storage

A technology that records data and stores it in a microscopic grid of cells on a non-volatile, erasable, low-power chip. 84

Optical storage

A technology that records data as light and dark spots on a CD, DVD, or other optical media. 81

Volatile

A term that describes data (usually in RAM), which can exist only with a constant supply of power. 72

Microprocessor clock

A timing signal that sets the pace for executing instructions in a microprocessor. 67

Trackpad

A touch-sensitive surface on which you slide your fingers to move the on-screen pointer. 89

Nanosecond

A unit of time representing one billionth of a second. 73

Data bus

An electronic pathway or circuit that connects the electronic components (such as the processor and RAM) on a computer's motherboard. 94

Black screen of death

An error condition in which a PC "freezes" and displays a black screen (blue screen prior to Windows Vista); usually turning the computer off and turning it on again clears the error. 103

Mouse

An input device that allows the user to manipulate objects on the screen by clicking, dragging, and dropping. 88

Joystick

An input device that looks like a small version of a car's stick shift. Popular with gamers, moving the stick moves objects on the screen. 89

Trackball

An input device that looks like an upside down mouse. The user rolls the ball to move the on-screen pointer. 89

Pointing device

An input device, such as a mouse, trackball, pointing stick, or trackpad, that allows users to manipulate an on-screen pointer and other screen-based graphical controls. 88

Non-volatile

Any electronic component that does not require a constant supply of power to hold data. 84

Portable computer

Any type of computer, such as a notebook computer, that runs on batteries and is designed to be carried from one location to another; also called a mobile computer. 59

Drive bays

Areas within a computer system unit that can accommodate additional storage devices. 86

Level 1 cache (L1 cache)

Cache memory built into a microprocessor chip. L1 cache typically can be read in one clock cycle. 68

Level 2 cache (L2 cache)

Cache memory that is located in a chip separate from the microprocessor chip. 68

Solid state drive

Data storage device that utilizes erasable, rewritable circuitry. 84

OLED

Display technology that uses organic light emitting diodes imprinted on a thin, plastic backing. 90

Capacitors

Electronic circuit components that store an electrical charge; in RAM, a charged capacitor represents an "on" bit, and a discharged one represents an "off" bit. 72

Overclocking

Forcing a computer component, such as a microprocessor, to run at a higher speed than intended by the manufacturer. 70

Response rate

In relation to display technology, response rate is the time it takes for one pixel to change from black to white then back to black. 90

Mod

In the context of personal computers, a customized or "modified" system unit typically jazzed up with lights, chrome, and decals. 65

Lands

Non-pitted surface areas on a CD that represent digital data. (See also pits.) 81

Serial processing

Processing of data one instruction at a time, completing one instruction before beginning another. 69

Cache

Special high-speed memory that gives the CPU rapid access to data that would otherwise be accessed from disk. Also called RAM cache or cache memory. 68

Pits

Spots on a CD that are "burned" onto an optical storage medium to represent digital data. 81

Read-only technology

Storage media that can only be read from, but not recorded on. 82

Plug and Play

The ability of a computer to automatically recognize and adjust the system configuration for a newly added device. 97

Random access

The ability of a storage device (such as a disk drive) to go directly to a specific storage location without having to search sequentially from a beginning location. 77

Data transfer rate

The amount of data that a storage device can move from a storage medium to computer memory in one time unit, such as one second. 77

Viewing angle width

The angle at which you can clearly see the screen image from the side. 90

System unit

The case or box that contains the computer's power supply, storage devices, main circuit board, processor, and memory. 57

Storage density

The closeness of the particles on a disk surface. As density increases, the particles are packed more tightly together and are usually smaller. 77

Hard disk platter

The component of a hard disk drive on which data is stored. It is a flat, rigid disk made of aluminum or glass and coated with a magnetic oxide. 78

Form factor

The configuration of a computer's system unit; examples include tower, mini-tower, pizza box, and cube. 58

Resolution

The density of the grid used to display or print text and graphics; the greater the horizontal and vertical density, the higher the resolution. 91

Recordable technology

The devices and standards that allow computers to write data permanently on CDs and DVDs, but does not allow that data to be changed once it has been recorded. 82

Rewritable technology

The devices and standards that allow users to write data on a storage medium and then change that data. 82

Access time

The estimated time for a storage device to locate data on a disk, usually measured in milliseconds. 77

Read-write head

The mechanism in a disk drive that magnetizes particles on the storage disk surface to write data, or senses the bits that are present to read data. 78

Word size

The number of bits that a CPU can manipulate at one time, which is dependent on the size of the registers in the CPU, and the number of data lines in the bus. 68

Color depth

The number of bits that determines the range of possible colors that can be assigned to each pixel. For example, an 8-bit color depth can create 256 colors. 91

Storage medium

The physical material used to store computer data, such as a floppy disk, a hard disk, or a CD-ROM. 76

Expansion bus

The segment of the data bus that transports data between RAM and peripheral devices. 94

Parallel processing

The simultaneous use of more than one processor to execute a program. 69

Dual-channel architecture

The use of two channels to quickly transport data between RAM and the processor. 73

DVD-R

see DVD+R 83

BD-ROM

(Blu-ray ROM) A Blu-ray disc that cannot be modified; usually used to distribute movies.

BD-R

(Blu-ray disc recordable) A Blu-ray disc that can be recorded on one time. 83

BD-RE

(Blu-ray disc rerecordable) A Blu-ray disc that can be recorded on multiple times.

CD-DA

(Compact Disc Digital Audio) The format for commercial music CDs, typically recorded by the manufacturer. 82

CD-RW

(Compact Disc ReWritable) CD-RW is a type of optical disc technology that allows the user to write data onto a CD, then change that data much like on a floppy or hard disk. 83

CD-ROM

(Compact Disc Read-Only Memory) The read-only data format that is stamped onto a CD, usually by the manufacturer. 83

CD-R

(Compact Disc Recordable) CD-R is a type of optical disc technology that allows the user to record data once on a disc. 83

CD

(Compact Disc) An optical storage medium used to store digital information. CD-ROMs are read only. CD-Rs and CD-RWs can be used to record data. 81

CISC

(Complex Instruction Set Computer) A general-purpose microprocessor chip designed to handle a wider array of instructions than a RISC chip. 69

DVD+RW

(Digital Versatile Disc ReWritable) A DVD technology that allows recording and changing data on DVDs. 83

DVD+R

(Digital Versatile Disc Recordable) A DVD data format that, similar to CD-R, allows recording data but not changing data on a DVD. 83

DVD

(Digital Video Disc or Digital Versatile Disc) An optical storage medium similar in appearance and technology to a CD but with higher storage capacity. 81

EEPROM

(Electrically Erasable Programmable Read-Only Memory) A type of non-volatile storage typically used in personal computers to store boot and BIOS data. 74

Front side bus

(FSB) The data bus that carries signals between the CPU and RAM, disks, or expansion slots. 68

LCD

(Liquid Crystal Display) Technology used for flat panel computer screens typically found on notebook computers. 90

RAM

(Random Access Memory) Computer memory circuitry that holds data, program instructions, and the operating system while the computer is on. 71

ROM

(Read-Only Memory) Refers to one or more integrated circuits that contain permanent instructions that the computer uses during the boot process. 73

RISC

(Reduced Instruction Set Computer) A microprocessor designed for rapid and efficient processing of a small set of simple instructions. 69

Pixels

(Short for picture element) The smallest unit in a graphic image. Computer display devices use a matrix of pixels to display text and graphics. 90

SVGA

(Super Video Graphics Array) Typically refers to 800 x 600 resolution. 91

SXGA

(Super eXtended Graphics Array) A screen resolution of 1280 x 1024. 91

UXGA

(Ultra eXtended Graphics Array) A screen resolution of 1600 x 1200. 91

UPS

(Uninterruptible Power Supply) A battery-backed device designed to provide power to a computer during blackouts, brownouts, or other electrical disruptions. 100

USB

(Universal Serial Bus) A high-speed bus commonly used for connecting peripheral devices to computers. 96

VGA

(Video Graphics Array) A screen resolution of 640 x 480. 91

WQXGA

(Wide Quad eXtended Graphics Array) 2560 x 1600 resolution. 91

WUXGA

(Widescreen Ultra eXtended Graphics Array) A display resolution of 1920 X 1200 pixels. 91

Dot pitch

(dp) The diagonal distance between colored dots on a display screen. Measured in millimeters, dot pitch helps to determine the quality of an image displayed on a monitor. 90

XGA

(eXtended Graphics Array) Usually refers to 1024 x 768 resolution. 91

DVD-Video

82,452

DVD-ROM

A DVD disc that contains data that has been permanently stamped on the disk surface. 83

DVD-RW

A DVD technology similar to DVD+RW that allows recording and changing data on DVDs. 83

Double layer DVD

A DVD that essentially stacks data in two different layers on the disk surface to store 8.5 GB, twice the capacity of a standard DVD. 81

Sequential access

A characteristic of data storage, usually on computer tape, that requires a device to read or write data one record after another, starting at the beginning of the medium. 77

Hard disk controller

A circuit board in a hard drive that positions the disk and read-write heads to locate data. 79

Graphics card

A circuit board inserted into a computer to handle the display of text, graphics, animation, and videos. Also called a video card or graphics board. 91

Expansion card

A circuit board that is plugged into a slot on a computer motherboard to add extra functions, devices, or ports. 95

Head crash

A collision between the read-write head and the surface of the hard disk platter, resulting in damage to some of the data on the disk. 80

Peripheral device

A component or equipment, such as a printer, that expands a computer's input, output, or storage capabilities. 56

Hard disk drive

A computer storage device that contains a large-capacity rigid storage surface sealed inside a drive case. Typically used as the primary storage device in personal computers. 78

Linux platform

A computer that is running the Linux operating system. 64

Desktop computer

A computer that is small enough to fit on a desk and built around a single microprocessor chip. 58

Virtual memory

A computer's use of hard disk storage to simulate RAM. 72

Card reader

A device that can be used to read and record data on solid stage storage devices, such as flash memory cards. 84

Surge strip

A device that filters out electrical spikes that could damage computer equipment. 100

USB hub

A device that provides several auxiliary USB ports. 96

Touch screen

A display device that accepts input from being touched with a stylus or fingertip. 89

PC platform

A family of personal computers that use Windows software and contain Intel-compatible microprocessors. 64

Mac platform

A family or category of Macintosh-compatible personal computers designed and manufactured by Apple Computer. 64

Blu-ray

A high-capacity storage technology that stores up to 25 GB per layer on Blu-ray discs (BDs). 81

Gigahertz (GHz)

A measure of frequency equivalent to one billion cycles per second. 67

Megahertz (MHz)

A measure of frequency equivalent to one million cycles per second. 67

Duty cycle

A measurement of how many pages a printer is able to produce per day or month. 93

Storage device

A mechanical apparatus that records data to and retrieves data from a storage medium. 76

Safe Mode

A menu option that appears when Windows is unable to complete the boot sequence. By entering Safe Mode, a user can gracefully shut down the computer, then try to reboot it. 105

Graphics processing unit (GPU)

A microprocessor dedicated to rendering and displaying graphics on personal computers, workstations, and videogame consoles. 91

Multi-core processor

A microprocessor that contains circuitry for more than one processing unit. 69