Computing Hardware Glossary

Alan Wood

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This is a glossary of terms used in PC hardware, with a few terms from software.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Address - A number specifying which of something - which memory location, which machine on a network, a position on a graphics screen etc.
Address Bus - A set of wires used to send an address to the memory; the memory uses this address to decide which data item (i.e. which memory location) is to be read (and sent to the processor) or written (copied from the processor); the memory send or receives the data for the memory via the data bus.
ADSL - (Asymmetric Digital Subscriber Line) A WAN connection for higher-speed connections between networks. Used over telephone wiring, often to connect home PCs to the Internet.
AGP - (Advanced Graphics Processor, or Accelerated Graphics Port) A connection for higher-speed graphics cards, faster that PCI slots. Usually as a slot for an AGP Expansion Card, but maybe on board. Gives transfer rates of 266Mbps up to 1Gbit per second. AGP slots & cards use a dual-row edge connector.
ALU - Arithmetic Logic Unit - a device in the processor which does numeric calculations
AMD - (Advanced Micro Devices) manufacturer of integrated circuits, such as the Athlon and Duron PC processors. See Slot A
AMR - (Audio/Modem Riser) an Intel specification, packaging the analog I/O audio functions of modem circuitry together with a codec chip on a small board, plugging onto a motherboard.
Analogue - Operating using continuously variable quantities- such as voltages, which may take on any value, not just discrete quantized levels. As opposed to Digital.
Application Program - The programs that do the computing tasks for the user - e.g. word processors and web browsers.
ATX - A specification for the size, power supply and connections of a motherboard; dimensions are 12x9.6 inches.
AUI - (Attachment Unit Interface) - a specification for connection between a computer and a network transceiver. [picture]
Back Side Bus - In a PC, the bus connection between the processor and the Level-1 cache memory. See also FSB.
Baud - A measure of data transfer rate, across a communications link. Not necessarily the same as "bit rate".
Berg - the connector for powering floppy disk drives. [picture]
Binary - A number system working in Base 2, and so using only the digits one (1) and zero (0). See Digital, Bit and Hexadecimal.
BIOS - (Basic Input-Output System) - software stored in ROM on the motherboard, which provides the self-test programs and the interface between the operating system and the motherboard hardware
Bit - A single, binary digit, capable of representing one of only two values - which might be true/false, on/off, black/white, 0/1, or any other two-valued item. See also binary number lecture notes.
Bit Rate - A Measurement of the speed of a digitial data transfer, such as a network connection; usually measured in bps.
Bitmap - An area of memory used to represent all the individual pixels of a graphics screen
Block - The smallest division of data on a disk drive, specified by track/sector/surface
BMP - A windows picture-file format; mostly no compression, but very recent programs can also use simple, lossless compression in this format.
Board - another name for a PCB, a card.
Boot Disk - A disk you can start the computer up from; a floppy disk or CD can allow you to start up a computer whose operating system is faulty, to fix problems or load a new OS.
bps - abbreviation for Bits per Second. A measure of data transfer speed, used in networking, e.g. for modem speed. Usually as kilobits per second (kbps - 1000 bits per second) and Megabits per second (Mbps - million bits per second); see Metric Prefixes.
Burn - To write a CD on a CD-R or CD-RW recorder (or "burner").
Bus - A collection of wires used to carry digital signals in parallel. See also Expansion Slots.
byte - 8 bits of data. The basic measurement of the amount of data. See also kiloByte and MegaByte.
Cable Select - A setting on an IDE disk drive for using just one drive per cable.
Cache - A high-speed type of memory between the processor and the main memory, used to speed up access to main memory. In a PC, there are two kinds: the Level-1 is on the processor, Level-2 is on the Motherboard
Card - slang term for a PCB.
CD - (Compact Disk) - 4-inch mylar disk designed to store digital audio
CD-R - (Compact Disk Recordable) - CD-ROMs which can be written (recorded) on a PC, but not erased or reused once recorded, on a CD-R or CD-RW drive.
CD-RW - (Compact Disk ReWritable) - CD-ROMs which can be recorded, and re-recorded, on a PC on a CD-RW drive.
CDROM - (Compact Disk Read-Only Memory) - Compact disks used to store computer information, or the CD-ROM drive used to read them.
Celeron - A "low budget" version of the Intel Pentium processor
Centronics - A connector for the parallel interface found on many computers for connecting printers (etc), named after the printer manufacturer that invented the interface, although Epson further developed the PC version. [Picture]
Chip - Slang term for Integrated Circuit
Chipset - In a PC, the electronics that connect the processor to the memory, the disk interfaces and the Expansion Slots; see Northbridge and Southbridge.
Case - the box the computer is built into. Available in various formats, e.g. tower, desktop etc.
Clock - In a computer, the signal that controls the speed of the processor (or graphics card, sound card etc); the clock speed of the computer is measured in MegaHertz or GigaHertz. See also real-time clock.
CMOS Memory - (Complementary Metal-Oxide Semiconductor) - memory that is kept alive (i.e. made non-volatile by the motherboard battery, to run the real-time clock and remember the BIOS settings.
CMYK - Cyan, Magenta, Yellow, Black; colours used in colour printing inks to make all colours, and representing colours on the computer using these colours; compare with RGB.
CODEC - (COder/DECoder or COmpressor/DECompressor) either a chip or some software used for encoding & decoding digital sound or video. May be part of the Analog-Digital conversion, or just for coding/compressing data for transmission/reception
Cooler - Slang term for a heat sink or cooling fan.
CPU - Central Processing Unit - a Processor
Crash - a sudden computer failure; usually through a software fault. A "system crash" causes the whole machine to stop working; a "program crash" may just cause a program to stop, leaving the computer running otherwise.
Creative Labs - Most popular manufacturer of sound cards (SoundBlaster); also make modems and video cards.
CRT - Cathode-Ray Tube; the type of screen used in most TV and computer monitors, usually a large glass "vacuum tube", with electron guns at the back.
Crystal - An electronic component made from a quartz crystal, used to control the clock on the motherboard, and on video, sound and network cards.
Cursor - The pointer on screen.
Cylinder - A radial division of data on a disk drive, where the head stays at the same radius around the whole of all of the surfaces - that is, a cylinder is all the tracks, on all the surfaces, at the same radius. See track, sector and block.
D-Connector - A D-shaped connector plug & socket used for connecting Centronics printers, VGA monitors and RS232 devices. [picture]
Data Bus - A set of wires used to send data between the processor and memory. See address bus and bus.
Data - The computing term for Information. See also binary number lecture notes.
DDR - (Double Data Rate) - A form of memory where the reading and writing can occur on both edges of the FSB clock, making the memory up to twice as fast. {also Dial-on-Demand Routing - a networking technique}
Digital - operating using (discrete) numbers, as opposed to Analogue. In electronics and computing, this (almost always) means working in Binary - using two discrete voltage (or current, or charge, or switch position) levels to represent ones and zeros, and combining many of these to make larger numbers.
DIMM - Dual-Inline Memory Module; a memory board using a double-sided edge connector
DIN - (Deutches Industrial Norm) A standards body in Germany; DIN-type connectors are used to connect old-style keyboards, and miniature DINs connect PS/2 devices.
DIP Switch - (Dual-Inline Switch) - A small block of switches for setting binary values, sometimes used on a motherboard to set speeds and voltages.
Display - the device showing the computer output visually; usually a Monitor.
DMA - (Direct Memory Access) - input or output of data directly between a device and the memory, without going through the processor.
dots-per-inch - A measure of resolution, particularly for printers and scanners; measures how many pixels can be printed (or scanned) in one inch of the image.
dpi - abbreviation for dots-per-inch
DRAM - Dynamic Random Access Memory; RAM that must be frequently refreshed to make it remember its contents. See also SDRAM, Static.
drive - A device that carries a data storage medium, such as a disk or tape.
DVD - (Digital Versatile Disk) - a development of Compact Disks, holding up to 4.5 Gigabytes; usually used for storing video.
DVD-R - (Digital Versatile Disk - Recordable) - DVDs used for storing read-only computer data, recordable on a computer using a DVD-R or DVD-RW drive.
DVD-ROM - (Digital Versatile Disk - Read Only Memory) - DVDs used for storing read-only computer data
DVD-RW - (Digital Versatile Disk - ReWritable) - DVDs used for storing read-only computer data, recordable and erasable/rewritable on a computer using a DVD-RW drive.
DVI - (Digital Video Interface) a standard connection between digital video cards and displays. [picture]
Dynamic - Changing; in computer memory, dynamic RAM will only keeps it's data if it is read or written frequently, a process called "refreshing"; compare with static.
Edge Connector - a connector used on PCBs, made by extending the tracks to "fingers" on the edge of the board; often gold plated.
EDO - (Extended Data Out) - A form of memory where the reading and writing can overlap, making the memory faster.
EEPROM - Electrically-Erasable Programmable Read-Only Memory - a ROM which can be reprogrammed through applying voltages to special "programming" pins. See Flash.
EIDE - (Enhanced IDE) An extension of the IDE disk-drive connection standard; has replaced the original IDE.
EISA (- Extended ISA) An extension of the ISA standard, using an extra edge connector.
Embedded System - A computer "hidden" inside another piece of equipment, such as a mobile phone or engine management system.
Ethernet - The most common computer networking (LAN) system; see IEEE 802.3. Developed by Bob Metcalfe at Xerox, then at 3-Com; originally released as a standard by DEC, Intel and Xerox.
Evil Empire - Microsoft Corporation. (Formerly the Evil Empire was IBM)
Expansion Card - A PCB added to a computer; may be a vital part of the computer, such as the video display controller, or an "add-on" such as sound or modem. See PCI, AGP, ISA.
Expansion Slot - A space in a computer to add extra hardware - e.g. a an Expansion Card such as a Modem or NIC. See PCI, AGP, ISA.
Fan - in a computer, small fans are used to cool the power supply, and sometimes other components like the CPU or disks, and sometimes also the graphics card.
FAT 16 - File system used by DOS and Windows 95; can also be used by 98, NT and 2000, and on floppy disks.
FAT 32 - File system used by Windows 98, Me and XP.
FDD - Floppy Disk Drive
File System - The way the computer organises the data on the disk drives, defining how the sectors, blocks and tracks are numbered and indexed, and how filenames and folders are named and arranged. See FAT and NTFS.
FireWire - A serial interface giving high-speed (400Mbits per sec) connections for external disk drives, cameras, video etc. Also know as the IEEE 1394 standard.
Flash - (i) to reprogram an EEPROM;
(ii) a type of random-access memory used in digital cameras, MP3 players and memory keys. Available in various formats, including "compact flash" or "smartmedia" cards. Non-volatile - does not lose its contents when there is no power.
Flat Cable - Another name for ribbon cable.
Format - In a disk drive, write the pattern of sectors and tracks, with the numbering and file-allocation table (FAT) to initialise the disk.
Frequency - How often something happens; see Hertz, MegaHertz, clock, refresh.
Front Side Bus - See FSB.
FSB - (Front-Side Bus) - In a PC, the connection between the chipset and the main memory. The FSB speed controls the speed of the memory; typically 133MHz.
GB - GB: see Gigabyte; Gb - see Gigabit.
Gbps - Giga-bits per second - a measure of data transfer speed, 1Gbps = one billion (10⁹) bits per second (see also Metric Prefixes)
Gbyte - see Gigabyte.
GHz - GigaHertz; a unit for measuring of frequency; 1GHz = one billion (10⁹) times per second (see also Metric Units and Clock).
gif - (Graphics Interchange Format) - a file format for storing pictures, invented by Compuserve. Lossless compression; limited to 256 colours.
Gigabit - a billion (10⁹) bits. A large measure of data in networking.
Gigabyte - 1024 Megabytes, or about a billion (actually, 2³⁰ = 1,073,741,824) bytes - a measure of the amount of data or memory; see also Terabyte.
Graphics Card - Common name for the Video Controller in a PC.
Hardware - The bits of the computer you can see and hit with a hammer!
HDD - Hard Disk Drive.
Head - In a disk or tape drive, the component that reads and writes the data.
Heat Sink - a metal component used to carry away heat from an electronic component; there will usually be heat sinks on the processor and on the power-supply components, and sometimes on other parts like disks and graphics processors.
Hertz - the unit of frequency, usually abbreviated to Hz; 1Hz = once per second, or one cycle per second. (see also Metric Units, clock, refresh, kiloHertz, MegaHertz)
Hex - Abbreviation for Hexadecimal.
Hexadecimal - A base-16 numbering system, using the numbers 0-9, and the letters A-F representing numbers 10-16. Since 2⁴=16, each 4 binary bits can be written as a hex digit. See also Binary)
Hz - abbreviation for Hertz.
IC - abbreviation for Integrated Circuit.
IDE - (Integrated Device Electronics) - the most common method for connecting internal PC disk drives; each IDE interface can normally connect to two disk drives, a master and a slave drive. Normally connected using flat cables. See also cable select, SCSI Interface.
IEC Connector - (International Electrotechnical Commission) - the three-pin connector used to connect mains leads to equipment, such as the computer power supply.
IEEE - (Institute of Electrical & Electronic Engineers) - a body which (among other things) sets standards for electronics
IEEE 1394 - The FireWire standard.
IEEE 488 - A standard for interfacing measuring instruments to computers
IEEE 802.3 - A standard for 10Mbps or faster networking (developed from Ethernet); variants of this are the most common networking standard. Most of the PCs in the University use 100Mbps IEEE802.3 networking.
IEEE 802.5 - A standard for IBM token ring networking.
IEEE 802.11 - A set of standards for wireless networking; 802.11a at 54Mbps; 802.11b (WiFi) at 11Mbps and 802.11g at 54Mbps.
Inch - An American and former Imperial unit of length, equal to 25.4mm. Used a lot in computer hardware, for historical reasons.
Intel - A manufacturer of integrated circuits, such as the Pentium and Celeron PC processors
Interface - A connection between two (or more) devices; see IDE, parallel, USB, SCSI.
Interlace - "interleaving" - drawing only every second line of a video display, so that it takes half the time to scan down the screen, reducing flicker; of course it then takes two scans to draw the whole screen.
Integrated Circuit - (IC) - a silicon chip; a complex electronic circuit built onto a small slice of silicon, and packaged into a small box with "pins" to connect it.
IP Address - Internet Protocol Address. The network address of a computer on the Internet. Set in software; compare with MAC Address.
I/O - Input/Output - refers to getting signals and/or data in and out of the computer (or part of the computer, or software).
IRQ - (Interrupt Request) a signal going between a peripheral device and the processor to "ask for attention"; a PC has 16 hardware interrupts.
ISA - (Industry Standard Architecture) - An old style of expansion slot used to add Expansion Cards on a PC Motherboard. Also called AT slots. Developed for the original IBM AT computer. See also EISA, PCI.
ISDN - (Integrated Digital Services Network) - A type of WAN connection, which can be used to connect home PCs to a network.
jpeg - see JPG.
jpg - (Joint Photographics experts Group; also JPEG) - a file format for storing photographs; lossy compression
Jumper - a pair of pins for setting binary values onto hardware devices, such as master/slave switching on IDE disk drives.
kb - see kilobyte.
kbps - kilo-bits per second - a measure of data transfer speed, 1kbps = one thousand (10³) bits per second (see also Metric Prefixes)
kbyte - see kilobyte.
kHz - kiloHertz; a unit for measuring of frequency; 1kHz = one thousand times per second (see also Metric Units)
kilobyte - 1024 (2¹⁰) bytes - a measure of the amount of data or memory. See also binary number lecture notes.
kiloHertz - See kHz.
LAN - (Local Area Network) - a computer network under the control of one organisation and covering a small area, such as a single building.
Li-Ion - Lithium Ion - a type of rechargable battery used in laptop computers and other portable equipment. Better than NiMH, and much better than NiCd batteries.
Linux - A free PC operating system based on Unix; there are many versions, for example Red Hat fedora, SuSE, Mandrake. "Paid for" versions with technical support are also available.
Lithium - an element; a name used to describe LiIon rechargable batteries, and some small, long-life "watch-type" batteries.
Local Area Network - See LAN.
MAC Address - (Media Access Controller Address) The hardware network address on an Ethernet network, encoded into a ROM chip on the NIC. See IP Address.
Main Board - Another term for the motherboard.
Main Memory - The main, processing memory of a computer, as opposed to the cache memory, the ROM, or the video memory
Master - in an IDE interface, the disk which will be searched first - so on a "primary" interface, the one which will be drive C: on a windows PC.
Mb - MB = Megabyte; Mb = Megabit.
Mbps - Mega-Bits per second - a measure of data transfer speed, 1Mbps = one million (10⁶) bits per second (see also Metric Prefixes)
Mbyte - see Megabyte.
MDC - (Mobile Daughter Card) is equivalent to AMR but for use in mobile computers.
Me - A version of Windows, released around 2000; stands for "Millennium Edition".
Megabit - a million bits. Used as a measure of network capacity (see bps).
Megabyte - 1024 kilobytes, or about a million (actually, 2²⁰ = 1,048,576) bytes - a measure of the amount of data or memory.
MegaHertz - See MHz.
Memory - The store the computer uses to keep programs and data whilst the computer is working on them. See RAM, ROM, Flash.
Memory Key - A small (keyring sized) device - usually plugging into the USB, and made from Flash memory - which emulates a disk drive - allowing transfer of files between computers. Also known as a "key drive" or "pen drive".
MHz - Megahertz; a unit for measuring of frequency; 1MHz = one million (10⁶) times per second (see also Metric Units and Clock)
Microcontroller - A microprocessor which includes most of the requirements of a whole computer, such as memory and I/O Devices. Used for embedded systems such as machine controllers.
Microprocessor - A processor on a single chip or IC.
microsecond - one millionth of a second (10^-6s, abbreviated to µs). See also millisecond, nanosecond, Metric Units.
MIDI - (Musical Instrument Digital Interface) A way of writing music as computer code, similar to sheet music. Includes definitions of how hard a note is played, which note and for how long. Can be played through a MIDI-interfaced musical instrument, or a synthesiser on a sound card.
millisecond - one thousandth of a second (10^-3s, abbreviated ms, or 1000µs). See also nanosecond, microsecond, Metric Units.
MODEM - (MODulator/DEModulator) A device for connecting a computer to a communications line (usually a telephone line); used for connecting PCs to the Internet. (Also connecting FAX machines to other FAX machines across the telephone system.) Speed is measured in bps.
Molex - the connector for power to hard disk & CD drives. Named after a manufacturer of many sorts of connector. [picture]
Monitor - A (separate, not built-in) computer display screen; see Refresh, CRT, TFT.
Motherboard - The main circuit board (PCB) in a PC, which the processor, memory and Expansion Cards plug into. Also usually carries the chipset and interfaces for the printer, USB devices, keyboard etc.
MP3 - MPEG-II level 3 file format; a video file format often used to compress music recordings for distribution over the Internet or playing on an MP3 player. See MPG.
MP3 Player - A portable device, like a cassette Walkman, for playing MP3 audio files. Often uses Flash Memory.
mpeg - see MPG.
mpg - (Motion Picture experts Group; also MPEG) - a file format for movies; lossy compression
ms - abbreviation for millisecond.
nanosecond - one billionth of a second (10^-9s, abbreviated to ns). See also millisecond, microsecond, Metric Units.
Network - A computer network connects computers together - for communication and resource sharing. See NIC, MODEM, IEEE 802.3 and ethernet.
NIC - (Network Interface Card) - the electronics to connect a PC to a network, usually an IEEE 802.3 network, and usually on an expansion card.
NiCad - Same as NiCd.
NiCd - Nickel-Cadmium - a type of rechargable battery used in laptops and other portable equipment. See also LiIon.
NiMH - Nickel-Metal Hydride - a type of rechargable battery used in laptops and other portable equipment. Better than NiCd, not as good as LiIon.
Northbridge - In a PC, the chip that interfaces between the PCI Slots & memory and the processor; with the Southbridge, forms the chipset.
ns - abbreviation of nanosecond.
NTFS - A file system used by Windows NT, 2000 and XP. More reliable than the FAT filesystems.
Object Code - Binary instructions; computer software in the form of binary numbers that the computer can understand, as opposed to source code.
OEM - (Original Equipment Manufacturer) - parts packaged for sale to a manufacturer - without "fancy" packing, extra software, instructions, cables etc. Compare with retail.
Operating System - The software system that runs the computer, and provides the "user interface", organises the memory and file system, and runs the application programs; examples are Unix, Linux, Windows - all of which come in various versions.
OS - Abbreviation for Operating System.
Parallel - many bits at a time; compare to Serial. The Centronics port found on many computers is a parallel interface.
Parity - an error-checking method used in memory; adds an extra bit used to flag if there are an even or odd number of ones in each byte. Special "parity-checked" memory boards and motherboard features are needed for this.
PCB - Printed Circuit Board - a board with electronic circuit components fixed to it and wires "printed" onto it. See Motherboard and Expansion card. Also called a "card".
PCI - (Peripheral Component Interconnect) Expansion slots used to add Expansion Cards on a PC Motherboard.
Pen Drive - See Memory Key.
Pentium - An Intel PC processor, developed after the 80486, through the Pentium, Pentium-II, Pentium-III and Pentium-4 {and other variants}.
pixel - From "PIcture ELement" or "PIcture cELl" - a single dot on a computer graphics display or printout.
Platter - name for a single hard disk element; a hard disk drive often has several platters, having two sides (surfaces) each.
plug-and-play - (PnP) A system which detects hardware devices connected to the computer, and finds and sets up the software for each device; this means devices can be connected to a computer and automatically work without the user needing to do any "installation".
PnP - abbreviation for "plug-and-play". {Also PNP is a type of transistor}
POST Codes - "beep codes" - patterns of long and short beeps indicating failure of the POST.
POST - Power-On Self Test - the tests done at startup to check the computer hardware is working
Power-PC - The processor used in recent Macintosh computers.
Power Supply - the proper name for the PSU.
Processor - The "brain" of the computer: the device that actually runs the program instructions, storing data in the memory, sending data to the outputs and getting data from the inputs. See Celeron, Pentium, AMD and Power-PC.
Program - A set of computer instructions for a particular task; one piece of software.
PS/2 - an interface commonly used to connect keyboards and mice; uses miniature DIN connectors.
PSU - (Power Supply Unit) - the device that converts the high-voltage AC electricity from the wall socket into low-voltage DC currents for the computer components. Usually a rectangular metal box in the corner of the case.
Quartz - Silicon Dioxide (SiO₂); see crystal.
RAM - Random Access Memory; memory which can be read and written - i.e. modified. Usually "volatile". See also SIMM, DIMM, dynamic and ROM.
RAMBus - A faster type of RAM.
Real-Time Clock - the device, usually run by a battery on the motherboard, which holds the date and time-of-day. Not the same as the processor clock; see also CMOS Memory.
Refresh - "update".
(i) In graphics displays, this means to redraw the screen; a high "refresh rate" (measured in Hz) means less flicker. Video refresh rates vary between about 50-100Hz.
(ii) In dynamic RAM, refreshing prevents the memory from "forgetting" its contents.
Resolution - a measure of detail in computer graphics; usually expressed in a number of pixels vertically & horizontally (for a screen) or dots-per-inch (for a printer)
Retail - parts packaged for sale in a shop - with "fancy" packing, may have extra software, instructions, cables etc. Compare with OEM.
RGB - Red, Green, Blue - the colours used to make all the colours displayed on a computer video screen, and representing colours this way. Also sometimes the connection method for monitors. See also CMYK
Ribbon Cable - Flat, multi-bit cables; used in a PC to connect disk drives and sometimes back-panel connectors.
RJ11 - (RJ=Registered Jack) small, American telephone connector; used to connect Modems to the phone cable.
RJ45 - (RJ=Registered Jack) larger, telephone-type connector; used to connect to IEEE 802.3 twisted-pair networks to the computer. (also used for other things, like console ports on network devices, ISDN connections etc.)
ROM - Read-Only Memory; memory which can only be read from, and not written - i.e. permanent, "non-volatile" memory, which keeps its data even without power, and cannot be modified. See EEPROM, RAM, BIOS and video card.
RS-232 - The standard for serial communication on the serial port of a computer (also called V.24 and EIA/TIA-232)
SCSI - (Small Computer System Interface, pronounced "scuzzy") - a faster, more flexible method (interface)for connecting disk drives (and other devices) than IDE; there are various versions, which can connect 7 or 15 devices to the computer.
SDRAM - Synchronous Dynamic Random Access Memory
Sector - An angular division of data on a disk drive; see track and block.
Serial - one bit at a time - compare to Parallel. The Serial interface on some computers (and the USB interface are connections which communicate by sending one bit at a time, along a single wire; see USB, RS232.
SIMM - Single-Inline Memory Module - a memory board using an edge connector having (electrically) the same pins on both sides.
Slave - in an IDE interface, the disk which will be searched last. See Master.
Slot - short for Expansion Slot.
Slot 1 - the socket on a motherboard that holds some Celeron and Pentium-II and III processors.
Slot A - the socket on a motherboard that holds AMD processors.
Socket 370 - the socket on a motherboard that holds some Celeron & Pentium-III processors.
Socket 470 - the socket on a motherboard that holds some Celeron & Pentium-4 processors
Software - The instructions that the computer follows.
Sound Card - The PCB that produces sound from computer data; usually has a MIDI synthesiser on board.
Source Code - Computer software in the form of text, that the programmer can understand, as opposed to object code.
Southbridge - In a PC, the chip that interfaces between the disk interfaces, serial & parallel ports, & ISA slots and the processor; with the Northbridge, forms the chipset.
SRAM - Static Random Access Memory
Startup Disk - Another term for boot disk.
Static - Fixed, Unchanging; in computer memory, static RAM keeps it's data without needing to be read or written frequently; compare with dynamic.
SVGA - (Super VGA) - A video screen with a resolution of 800x600 pixels.
SXGA - A video screen with a resolution of 1400x1050 pixels
TB - abbreviation of Terabyte.
Terabyte - A very large amount of data - 1024 Gigabytes, or 2⁴⁰ bytes. See also Metric Prefixes.
TFT - Thin Film Transistor - a type of flat-panel display.
Track - A radial division of data on a disk drive, where the head stays at the same radius around the whole of one surface. See sector and block.
Track Ball - A pointing device like an upside-down mouse, where a ball is turned to move the cursor on screen.
Transistor - an electronic device, used in computers as a switch. Can be made very small, and to use very little power. Many millions of transistors are now made on each CPU chip, such as the Pentium.
Trojan (or Trojan Horse) - a program "pretending" to be something else; may be harmful. See also Virus, Worm.
USB - (Universal Serial Bus) - a method of connecting external devices to the computer, such as printers, keyboards, modems, disk drives etc, using a high speed (12Mbytes per sec) serial interface; designed to be plugged in and out whilst the computer is running, and to be fully "plug-and-play". USB uses two connectors: USB-A & USB-B.
USB II - A faster version of Universal Serial Bus.
UXGA - A video screen with a resolution of 1600x1200 pixels
Vacuum Tube - (a U.S. term; also known as a "valve") an early electronic device, made of glass, with all the air removed. Valves were large and parts of them had to run red-hot; this meant they used a lot of power, and were unreliable. Used in early computers, but replaced in the 1960s by transistors (in TV sets, replaced by transistors in the mid-1970s). Valves are still used as CRT displays, and in guitar amplifiers.
Valve - a (British) name for a Vacuum Tube.
VGA Card - Common name for the Video Controller or Graphics card in a PC.
VGA - (Video Graphics Array) - a 640x480 pixel computer display resolution; also used to name the D-connector used for monitor connection.
Video Card - Common name for the Video Controller in a PC.
Video Controller Card - The PCB that makes the "video signal", or the image, to display on the screen. May be an Expansion Card or built-in (on-board) to the Motherboard. Has it's own processor, clock, RAM and ROM. Also known as VGA card, Graphics card.
Virus - A piece of computer software designed to replicate itself onto many computers; may be very harmful. See also Worm, Trojan.
Volatile - In a computer- "liable to disappear"; RAM is usually volatile memory - it's contents is lost when the power is turned off. ROM is non-volatile.
WAN - (Wide Area Network) - a computer network spanning a large area, usually between separate organisations and connecting LANs together. An example is the Internet.
Windows - a PC operating system from Microsoft; comes in various versions: 95, 98, Me, NT, 2000, XP. See also Linux
Worm - similar to a virus; a piece of computer code that replicates itself by spreading to computers across a network.
WYSIWYG - (Pronounced "wizz-ee-wig") - "what you see is what you get" - describes a system where what you see on the screen looks very like what is printed out.
XGA - A video screen with a resolution of 1024x768 pixels
XP - A version of Windows introduced in 2001. Comes as XP-Home and XP-professional. Office XP is the version of Microsoft Office released at the same time.
Yahoo - A web searcher, directory and and other service provider
ZIF socket - (Zero Insertion Force socket) - a socket for an Integrated Circuit with a mechanism to release or hold the chip without using force on the chip itself. Used for processors.