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

5.1 CHANNEL SURROUND

Surround sound configuration used in home cinema systems with five high quality sound channels (front and rear stereo and centre dialogue channel) plus one narrow bandwidth channel carrying low frequency (bass) effects

286, 386, 486

Families of Intel microprocessor chips developed during the 1980s and early 1990s, forerunners of the Pentium chips used in current generation PCs

A

AAC

Advanced Audio Coding -- audio codec used on Apple iPOD personal music players and distributed by  Apple iTunes  online music store

ACTIVE-X

Programming tools used to integrate multimedia components and features into web pages

ADSL

Asymmetric/Symmetric Digital Subscriber Line – ‘Broadband’ high-speed data connection using existing telephone lines. ADSL has the facility to be "always on" and permits normal operation of the phone, to make and take calls whilst the connection is active.

A/D CONVERTER

Device that converts analogue audio signals into digital data

ADWARE & SPYWARE

Programs secreted in web pages or software downloads that makes use of your Internet connection – without your knowledge or permission -- to display advertising or send personal or private data from your PC to a parent site

AGP

Accelerated Graphics Port – dedicated socket on a PC motherboard for high performance ‘3D’ video adaptor cards required for demanding graphics applications and the latest games

ALGORITHM

A program or piece of software that processes data in a carefully ordered sequence of steps or according to a precise set of rules ASCII

ANTI STATIC BAG

Made from specially treated plastic, designed to disperse a static electric charge

APS

Advanced Photographic System – film camera format with easy to load cartridges and improved creative facilities

ASCII

American Standard Code for Information Interchange -- a universal data code for text and alphanumeric characters, understood by virtually all computers 

ASPECT RATIO

The shape of an image, defined by the relationship between its height and width

AT

ATtention - the prefix to a modem command, to tell the modem to expect an instruction

ATA/IDE

Advanced Technology Attachment/Integrated Drive Electronics; the circuitry -- built into the disc drive – that acts as an interface between the drive and the PC motherboard (see also SATA)

ATAPI

AT Attachment Packet Interface - industry standard disc drive connection system and data communications protocols, used on the most CD-rewriters, suitable for use with most Windows PCs

ATRAC

Adaptaptive Transform Acoustic Coding - digital audio compression system used by the MiniDisc format

ATOMIC CLOCK

By analysing the vibrations of certain atoms (Caesium is the favourite) it is possible to measure time to an accuracy of a few billionths of a second per day

ATTACHMENT

Data file – usually containing a photograph or text document but sometimes a worm or virus – sent with an email message

ATX

Motherboard layout standard, defined by Intel, covering the physical size (305 x 244mm), position of sockets, expansion slots and mounting holes

AUTOCORRECT

Word feature that automatically corrects spelling mistakes as you type

AUTOTEXT

A frequently used block of text - an address, salutation etc., -- that can be inserted into a document

AVERY LABELS

A range of standardised label styles and formats, developed by the office equipment company of the same name

.av

Audio-Video Interleaved, standard format for PC video files

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B

BACKCHANNEL

The return path, to the Internet Service Provider (ISP), for web page requests, outgoing email and data sent from a PC

BAD SECTORS

Parts of the hard disc drive which the test utility Scandisk marks as being faults and incapable of reliably storing data. A sudden increase in the number of bad sectors is often a sign that the drive is damaged or starting to deteriorate

BANDING

Straight lines or bands across a printed picture caused blocked nozzles, poor alignment or design defects in the printer head, as it criss-crosses the paper

BCC

Blind Carbon Copy, sends a copy of a message to several recipients, but without showing details of the other recipients on the email

BETA

Pre-release version of a program or application, made available to testers and volunteers on an at-their-own-risk basis, to help identify any last remaining bugs, glitches and conflicts

BINARY

Numbering system with a base of 2, where values are represented by zeros and ones

BIOS

Basic Input Output System: diagnostic and configuration program stored in a microchip memory on the PC motherboard that checks the PC hardware before the operating system is loaded

BITMAP

Type of image file format (extension *.bmp) used by Windows and many other programs, quality is high because no compression is used; however, bitmap files can be very large and are unsuitable for sending via email

BITRATE

A measure of the amount of digital data a system can process, measured in bits per second or 'bps', in the context of MP3 faster bit rates mean lower compression and higher sound quality

BITS PER SECOND (bps)

The number of bits per second a serial communications system can handle determines how fast information can be conveyed from one point to another

BLACKLIST

Library of known spammers, addresses, keywords, names and terms used by anti-spam software to filter incoming email

BLOCKED SENDERS

List of email addresses – specified by the user -- that automatically deletes unwanted messages

BLOG

Short for Weblog, a web page carrying an on-line diary or frequently updated content

BLUETOOTH

Short-range (5 to 10 metres) wireless communications system used to link electronic devices, like cell phones with hands-free headsets and PCs with printers and peripherals such as keyboards and mice

BOOLEAN SEARCH

Advanced technique using logical commands such as AND, OR, NOT etc., to refine a keyword or document search. (A branch of algebra named after nineteenth century British mathematician George Boole)

BOOT (REBOOT)

The process a PC goes through immediately after being switched on, this includes checking and configuring the hardware (see BIOS) prior to loading the operating system

BOOT ORDER

The sequence in which a PC checks disc drives and storage devices for a boot file or operating system. Most machines are configured to check either the primary hard drive (usually C:) or the CD-ROM drive first. Some recent PCs can also boot from external USB memory devices.

BROADBAND

High-speed Internet -- typically at least five times faster than a standard dial-up connection -- using a variety of technologies including ADSL, cable, satellite and wireless communications

BROWNOUT

A large reduction in the mains supply voltage, causing lights to dim and electronic devices like PCs to stop working

BROWSER

An Internet access program, such as Microsoft Internet Explorer, Opera and  Mozilla Firefox

BSOD

Blue Screen Of Death – appears when Windows crashes and needs to be rebooted

BURNER

CD writer, referring to the way data is recorded, using a laser beam to change the optical properties of chemicals sandwiched between the layers of a recordable disc 

BURN PROOF

Additional memory in a CD or DVD writer to prevent BUffer UndeRun, or interruptions in the datastream, which cause recording errors  

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C

CACHE

Part of a computer's memory set aside for storing frequently-used data, speeding up file access or the transfer of information

CAD/CAM

Computer Aided Design/Manufacture -- family of graphic-oriented software applications used in design and manufacturing

CARTRIDGE/TANK

Replaceable ink container in a printer

CADDY

Removable container for an optical disc or a hard disc drive, enabling it to be quickly extracted for storage or loading in another drive or PC

CARD READER

External device --connected by USB cable -- or built-in facility that allows a PC to read and write data to a memory card. Most current card readers are ‘multi-format’

CCD

Charge Coupled Device, type of microchip used in digital cameras, web cams, camcorders and video cameras, containing hundeds of thousands or millions of light sensitive picture elements or 'pixels' 

CD-A

Compact Disc Audio, the industry standard file format for audio CDs, that will ensure that discs can be played on any CD player

CD-R

Compact Disc Recordable, write-once recordable CD format

CD-R/RW

Compact Disc Read/Write, disc that can be recorded on and erased many times

CHAT-ROOM

Web page or site, which allows subscribers or members to exchange text messages

CHIPSET

Control microchips on a PC motherboard or plug-in adaptor card

CLIENT

A PC or program used to access files on another PC on a network

CLIP ART

Copyright-free pictures, icons, cartoons and graphics supplied with word processor programs, or available separately on disc or from thousands of web sites on the Internet

CLIPBOARD

Windows utility used to temporarily store chunks of text, data, graphics or pictures that can be shared or imported into other applications using Copy and Paste

CLIPPING

Distortion caused by excessively high recording level

CLONE BRUSH

Graphic program tool for copying an area of a picture, to replace colours and textures

CMOS

Complimentary metal oxide semiconductor - family of low power microchips used to store and process digital data

CODEC

Compression/decompression (or coder - decoder) software utility or add-on used to process digital data

COLD BOOT

Starting a PC from its switched-off state, as opposed to a Restart or Suspend or Hibernation modes

COMMAND LINE

A typed instruction, to tell a PC to do something, as opposed to clicking on a menu or icon

COMMAND PROMPT

DOS type operating mode that allows access to the PC's disc drives and files, without having to load Windows

COMPACT FLASH

Type of memory module used to store and move data between digital cameras, MP3 players etc. and PCs

COMPATIBILITY MODE

Facility in Windows XP to run older Windows (95/98) programs

COMPOSITE VIDEO (PAL)

Standard video signal format used by all consumer video devices, including TVs, VCRs DVD players etc. In the UK we use the PAL (Phase Alternate Line) colour system

COMPRESSION

A technique used to reduce the size of a file, making it smaller, more manageable and quicker to send over the Internet

CONSUMABLES

Printer ink and toner cartridges etc., which need to be replaced when they run out or exceed life expectancy

COBOL

Common Business Oriented Language - programming language used in data processing and business applications

COLOUR DEPTH

The amount of data used to describe a colour, which determines the range and accuracy of colours in an image

COLOUR MATCHING

Technique to ensure that the colours displayed on a PC monitor are as close as possible to the finished printed picture

COLOUR SCHEME

Colouration of Windows desktop and screen elements, such as task, tool and menu bars, active and inactive windows and drop-down menus

COLOUR TEMPERATURE

Means of describing the distribution of colours in a light source, measured in degrees Kelvin. (Typical values: tungsten lamp 2700k, fluorescent tubes 2700 to 6500k, noonday sun 5500k, blue sky 10000k)

CONTEXT MENU

A menu containing commands or actions relevant to an object or element on a program’s desktop or dialogue box

COOKIES

Small text files stored on a PC by web sites that can contain a wide range of data such as preferences and personal information

CORE FONTS

The basic set of fonts or typefaces that are installed and used by Windows 95/98

CPU

Central Processor Unit - the main microprocessor chip in a PC

CRITICAL UPDATES

Patches and fixes for the most serious vulnerabilities in Windows or an application that can affect its security or operation

CRT

Cathode Ray Tube – video monitor screen, basically a big glass bottle with all of the air sucked out. The image is formed on a layer of phosphor coating the side of the glass faceplate, which glows when struck by a stream of fast moving electrons

CSV (COMMA SEPERATED VALUES)

Text file where items of information – i.e. names, addresses, telephone numbers etc -- are separated by commas

CUSTOMISATION

Personal preferences applied to a program or application that determine how it looks, the layout of menu and toolbars and so on

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D

DAISY CHAIN

USB devices have two sockets so they can be connected together, one to the other, like a chain 

DATA CARTRIDGE

A cassette, similar to audio or video tape (Some tape backup systems use DAT and 8mm audio and video cassettes).

DATA FIELD

In the context of an address book a single item of information, i.e. a forename or surname, house number and street name, postcode etc.

DATA SOURCE

A file used to store a particular type of information is kept, such as names and addresses

DATA MINER

Program or software that collects information on a PC -- usually relating to web surfing -- and sent from the PC to a marketing company

DCC

Direct Cable Connection, a Windows utility for connecting two PCs together so they can exchange files

DECOMPRESS

Files sent over the Internet are often 'compressed' to make them smaller and faster to send. However, in order to use the files they have to be decompressed or extracted on the host PC. Some compressed files come with their own automatic extraction utility, others -- usually with the extension *.zip -- depend on a separate program on the PC to 'unzip' the files   

DEFRAG

Over time the files on a PC's hard disc drive become disorganized - 'defragging' the drive restores order and speeds up reading and writing data

DEGAUSS

Demagnetise -- a coil around the outside of a picture tube in a video monitor or colour TV induces a collapsing magnetic field that eradicates the build up of magnetic fields on metal components inside the tube, which case colour distortion

DDR/DIMM

Double Data Rate/Dual In-line Memory Module -- DIMM modules have 168 pins whilst DDR DIMM modules have 184 pins.

DHCP

Dynamic Host Configuration Protocol – system of automatically allocating IP addresses to computers in a network

DIAL UP CONNECTION

Utility in Windows responsible for connecting a PC, via a modem, to the Internet

DIGITAL ARTEFACTS

Processing errors in digital video recordings, typically the picture freezes momentarily or breaks up into large 'pixellated' blocks

DIRECTX

A software component in Windows (included as standard in Win 9x and XP) used to improve the graphics and sound performance of programs, especially games

DISC CONTROLLER

Microchip that identifies a disc drive or storage device to a computer and helps speed up the transfer of data

DISPLAY CARD/ADAPTOR

A plug-in card or circuitry incorporated into the motherboard that converts digital information into an analogue video signal that is fed to the monitor

DISPLAY SCHEME

A preset selection of colours, sizes and text formats assigned to Windows screen elements

DISTRIBUTION

A complete Linux package containing the main operating software, a ‘shell’ or desktop program plus a selection of popular applications

DITHERING

Sharpening edges and creating additional colours and shades by randomly interspersing pixels of other colours

DIVX

Highly efficient data compression system used to reduce the size of large video files to make them easier to transport over the Internet

DLL

Dynamic Link Library, a data file containing data or information needed by a program. DLLs may be shared by a number of applications, in which case they are stored in a central location, such as the System folder in Windows

DMA

Direct Memory Access - a means of transferring data quickly between the hard disc and the PC's memory (see EIDE)

DNS

Domain Name System -- used by the Internet to translate web site addresses into numeric Internet Protocol (IP) codes

DOMAIN

A group of computers, sharing a common address or identity, connected together by a network. Thus a desktop PC connected to the Internet via an Internet Service Provider is part of that ISP's 'domain'

DOMAIN NAMES (GENERIC TOP LEVEL)

.ac.uk

UK academic organisation

.com

world-wide 'commercial' entities, individuals or companies

.co.uk

UK based commercial entity, individual or company

 .edu

assigned to higher level educational establishments, colleges, universities etc.

.gov/.gov.uk

reserved for US government agencies and organisations and similar bodies in other countries when preceded by the relevant country code

.mod.uk

UK Ministry of Defence establishment web sites

.net

organisations, which are part of the Internet infrastructure - i.e. Internet Service Providers etc.

.nhs.uk

UK national health service web site

.org,/org.uk

originally reserved for non-profit making organisations (charities, political bodies, professional institutions, trades unions etc.)  but now issued to some commercial enterprises

.sch.uk

UK schools domain

DONGLE

A type of electronic key (‘dangling’ on the end of short wire) used to unlock some types of software or any small device that plugs into a PC

DOS/MS-DOS

Disc Operating System/Microsoft Disc Operating System -- a program that runs independently of Windows responsible for controlling disc drives, organising data and memory resources.

DOS MODE<