adventure game
computer-based game which allows the exploration of a scenario or story in which the player is an ‘adventurer’.

software tool which will search the world wide web according to a user’s specifications. Also known as a knowbot, bot or droid. See also search engine.

signal which does not vary in discrete steps, but continuously from one level to another. For storage, processing and communicating with computers, analog signals (such as the output of a microphone) are converted into digital form using analog to digital converters (A-to-D or A/D). This is called digitization, as the information is then stored in binary code. See also digital.

analog to digital converter see analog

anti-virus software see virus

display of a sequence of images to give the impression of movement. Simple animation programs are available.

pre-written, mini-programs (sub-routines) used on a web page to operate a specific function.

to store files which are not needed but cannot be discarded. This often involves backing up/saving to a separate hard disk, floppy disk or other storage medium. Also used for stored messages contributed to e-mail discussions, sometimes searchable by date, topic, contributor, etc.

acronym for ‘American Standard Code for Information Interchange’. Internationally adopted standard of numerical equivalents for characters representing numbers, letters, punctuation marks, symbols, and control codes. ASCII gives rise to plain text which can be read by most computers and most text-reading software.

file which is attached (linked) to and sent with an e-mail message.

authoring software
programs which help relatively inexperienced users create multimedia or hypertext documents.


back up
to make a duplicate but separately stored copy of the contents of a computer-held data set, software application, or individual files. Back-ups should be done regularly.

range of signal frequencies which indicates how much data can pass along a channel at one time. Broadband networks, the basis of the information superhighway, allow video signals to pass at high speed;

bar code
arrangement of vertical lines of varying thickness with spaces in between. A scanner is used to read the code.

BASIC (Beginners’ All-purpose Symbolic Instruction Code)
one of the easiest languages for writing programs. Many operating systems come supplied with a version of BASIC.

unit of measurement of data transfer speed (‘baud rate’), for example over a telephone line or to a printer. A baud is one single event per second, and so it can also be a character, digit or byte.

contraction of ‘binary digit’. The smallest unit of computer information, equal to either of the digits 0 or 1, called binary because it has only two values, on or off. See also byte.

graphic image held by a computer as a screen representation, with each bit relating to the setting of an individual pixel on the screen.

bits per second (bps)
unit of measurement of data transfer speed. For example, the bit rate of widely used modems is in the range 300 to 56000 bps (or 56 kbit/s: higher rates are given in kbit/s).

to start up a computer. The computer is regarded as ‘bootstrapping’ itself by loading the program which starts its operating system.

Braille notebook
portable computer in which the user keys in Braille, the system of representing letters with raised dots to allow reading by touch.

informally used to mean ‘faster than common networks’, and so the actual meaning depends on what is common at the time.

software used to search and retrieve information from the world wide web. Netscape, Microsoft Internet Explorer and ANT Fresco are browsers.

error or fault in computer software which causes it to malfunction.

bulletin board system (BBS)
electronic equivalent of a noticeboard, software on a central computer which allows users remote from it and each other to exchange information electronically via a network, e-mail or the world wide web.

unit of information equal to eight bits. Usually, each byte stores one character.


temporary memory used to access frequently used instructions, thus speeding up processing time. Also denotes temporary storage of world wide web pages by browser software.

CAD/CAM (computer aided design / computer aided manufacturing)
drafting and design with the aid of a computer which can handle technical geometric detail. CAD allows the user to manipulate drawings and view them from all angles.

circuit board that plugs into a computer to provide a new function, such as sound or video input and output.

case sensitivity
some software’s inability to construe upper and lower case versions of a letter as representing the same letter, so that, for instance, a browser may not be able to find a file if its name has an initial capital and you have given it in lower case.

CD-ROM (compact disk read-only memory)
computer storage medium, optical disk

CD writer (compact disk writer)
hardware device which can save information on to a CD.

CPU – central processing unit
Brain of the computer.

popular name for an integrated circuit, also called a ‘silicon chip’ as all the circuitry is etched on to a thin slice of silicon.

program or computer which asks for services from a server (a resource-providing computer).

clip art
library of copiable pictures (usually copyright-free)

temporary storage area for an item during its transfer from one part of a document to another or to another document, e.g. during cutting, copying and pasting.

short for communications, term used to refer to the linkage between computer systems to allow the transmission of information over a communications line, which can be an ordinary telephone system using a modem, a dedicated fibre optic cable or a satellite.

pieces of equipment and/or software which are capable of being used together without special modification or adaptation are termed ‘compatible’.

technique which reduces the amount of space required to store data. General compression techniques apply to any data, but better results can be obtained by using characteristics of the particular type of information, such as text, audio, image or video.

computer-mediated communications (CMC)
use of computers to communicate, as in computer conferencing and electronic mail.

concept keyboard
particular make of overlay keyboard. Used in restaurant, supermakets and bars.

conferencing see computer conferencing, tele-conferencing or video conferencing

set of instructions from a web server to a client machine. Cookies may be used by a web site owner to identify and track users of that site. Browsers can be customized to accept or reject cookies.

sudden failure of software or hardware, often resulting in no response to mouse or keyboard actions.

popular term for the internet, coined by William Gibson in his novel Necromancer, published in 1984.


representation of information – facts, concepts or instructions – in a formalized manner in order that it may be communicated, interpreted or processed by human or automated means. In computing, information that may be processed by a computer.

data capture/collection
acquisition and input of information for use on a computer using manual or computer input devices.

data compression see compression

data logging
acquisition of information by a computer through use of sensors to measure and record environmental changes – for example, the changes in temperature of water in a pond over the period of several hours.

data-logging software
software which is able to take the value of a parameter such as light level or temperature from a sensor/interface box and scale it to a meaningful measurement, such as SI units. It often also presents the value either as a big number for a class demonstration or as a value-versus-time graph.

Data Protection Act 1984
United Kingdom Act of Parliament which sets out rules for the storage of data about individuals. Defined data users must register with the Data Protection Registrar and comply with principles of fairness, privacy, confidentiality, relevance, accuracy, accessibility and security.

structured collection of conceptually related data or data files organized and stored in a computer system. Databases can be set up in different ways: for example, the simplest are tables with a row for each record (a set of related items such as an individual’s name and address) and a column for each field (the categories within each record such as last name, house number, street, town, etc.). Hierarchical databases hold their data in tree structures, e.g. one for a school might divide into staff and students at a high level, with individual names at the lowest and divisions like department or class in between. The most powerful databases use a method of storing data which does not restrict the way users can query it.

computer or software settings as set in the factory or by the software creator.

desktop computer
traditional office or personal computer. This has three or more parts linked together by cables: the system unit which houses the central processing unit and disk drives, the monitor, a keyboard and probably a mouse.

desktop publishing (DTP)
production via a desktop or personal computer of page layouts which combine words, graphics and images with different sizes and styles of type and form the master copies of materials such as newspapers, magazines and leaflets.

connection to the internet or another computer over an ordinary telephone line.

in computing, the representation of information as discrete digits, or bits. Contrasted with analog.

digital camera
camera which captures and stores images as digital (electronic) information. Images can be stored either on a memory chip in the camera, on disks or in some cases on plug-in memory cards.

digital data network
network specifically designed for the transmission of data in digital form, so that people, computers and other devices can communicate (e.g., ISDN).

digital versatile disk (DVD)
data storage medium, optical disk capable of storing high quality video as well as data such as programs, text, still images and sound (also known as ‘digital video disk’).

digitized speech
electronic means of recording, storing and reproducing human speech, similar to using a tape recorder. Digitized speech is increasingly used in electronic communication aids as well as or in place of synthesized speech.

digitizer see scanner


display resolution see resolution

domain name system (DNS)
hierarchical naming system used to locate computers on the internet, matching the number by which one networked computer recognizes another (the IP number) to a name which assigns the computer owner to a domain or category of user. Top-level domains are indicated by the abbreviations at the end of the name. For countries outside the US, top-level domains are countries (uk, au, fr). Within the US at the top-level and at the second level elsewhere, domain names describe degree-awarding universities (edu in the US, ac in the UK), commercial organizations (com, co), government agencies (gov), non-profit and charitable organizations (org), etc. The next level down, and often the first element of the name, is the name or alias of an organization or an individual, so that the Open University’s internet identity is open (name of organization) ac (type of organization) uk (country).

DOS (disk operating system)
standard operating system designed to manage files for personal computers, e.g. MS-DOS, developed by Microsoft for the IBM PC.

dots per inch (dpi)
measure of printer or screen resolution or quality. The higher the dpi the sharper and clearer the image.

to use one computer to obtain data from another computer, electronically. Downloaded information can be incorporated into other files, displayed, printed or saved.

dpi see dots per inch

to use a mouse or similar device to move material appearing on one part of the screen to another position. The material to be moved is chosen (selected) and marked, e.g. by highlighting text or putting a boundary around an area of an image. Often called drag-and-drop.

DVD see digital versatile disk

dynamic geometry
software which enables the user to create and manipulate geometric diagrams using points, lines, circles and standard constructions. Angles, lengths and areas can be measured. Some versions offer co-ordinate geometry and transformation geometry. Some versions also offer linked graphing and spreadsheet facilities.


e-mail (electronic mail)
messages or letters sent and received in electronic form via computers.

e-mail attachment see attachment

EDI (electronic data interchange)
system for exchanging trading information in standard form by computer systems through the use of electronic messaging systems – for instance, examination entries, personnel records and transactions between trading partners.

electronic communication aid see augmentative and alternative communication

electronic mail see e-mail

electronic whiteboard
interactive screen modelled on a standard whiteboard that is linked to a computer. The computer image is projected onto the screen, sometimes using a standard data projector (often ceiling mounted). The user interacts on the screen with a ‘pen’ and the screen sends information back to the computer about the pen’s movements, enabling the user to interact with various software packages.

to insert information stored in one format into information in another format, for example a graphic into a text file.

special type of printer that can produce Braille from a computer.

hardware or software which enables one type of computer to behave like another.

conversion of data into a format that cannot be read except with a special decryption program. Used on the internet for secure transactions.

expanded keyboard
keyboard which may include extra formatting options, a numeric key pad and the ability to customize key-press response times.

expansion card
card which slots into the motherboard of the computer to increase its functionality, e.g., a sound or graphics card.

extension see file extension


FAQ see frequently asked questions

favourites see hotlist

fax (facsimile)
transmission of images over the telephone network, most often of letters or other text. Fax messages can be sent direct from a desktop computer fitted with a fax modem.

fax modem
modem which, in addition to its normal data transmission capabilities, handles faxes. With suitable software, a fax modem allows a microcomputer to operate like a fax machine, in the sense that any electronic document can be printed to the fax modem and thus sent out as a fax. Some fax modems with suitable software allow the receipt of faxes and their display on the computer screen.

fibre optic cable
very thin strands of pure glass used for transmitting high volumes of data at high speed.

category in a database, roughly equivalent to a column in a table. Databases contain records (which are like the rows in a table) which have the same fields of information but for different individuals or objects, e.g. a database of club members has a record for each member which contains the fields ‘name’, ‘initials’, ‘membership status’, ‘number’.

collection of data held on a computer as one thing with one name. A file can be a piece of work created by the user in an application such as a word processor or a database. Each file needs a unique label (filename) in order to be accessed. See also directory.

file extension, filename extension
suffix which follows a user-created filename which allows the file type (e.g. word-processed document, spreadsheet) to be recognized by the computer. Common extensions are [filename].doc for a word-processed document and [filename].gif for an image.

file server see server

file transfer
to copy or move a file from one computer to another.

file transfer protocol (FTP)
common method of transferring files from one computer to another over the internet. See also protocol.

means of protecting a networked computer system to prevent unauthorized access.

floor turtle
programmable device, sometimes called a floor robot, controlled by Logo or Logo-like languages. The turtle can have a pen holder which can be lifted or dropped to trace the turtle’s movements on paper.

floppy disk
small portable data storage medium in which the disk is flexible (as opposed to a hard disk). Currently usually a 3.5 inch disk in a rigid plastic case. See also CD-ROM, hard drive.

font see fount

fount (US font)
family of type, complete set of letters, numerals etc. of one face and style. Each fount has a name (e.g. Times New Roman, Garamond, Gill) and can be displayed in different sizes. Many founts are available in different weights and variations, such as medium, bold, medium italic and so forth. Some are designed specifically for legibility.

free-text database
stores its information in normal written form: a written report, for example, could be held in full text reflecting its printed version. All words (in fields specified as searchable) can be searched for individually but, often, controlled vocabulary (such as keywords) is used as well.

software that can be copied and used without payment to the author.

frequently asked questions (FAQ)
list of the most frequently asked questions and their answers, produced as a reference document for individual e-mail discussion lists/groups or world wide web sites, in order to avoid repeating answers to the same questions.

full motion video
video signal before it has been processed by video compression.

fuzzy matching
‘guess’ by a searching, spelling or predictive word-processing program which achieves a near match to the user’s input , so that phonetic or poor spelling, for example, is not a barrier to communication.


device connecting different networks by carrying out protocol conversion between them, i.e. translating the rules of communication of one set of computers to those of another.

GIF (graphics interchange format)
format commonly used to store digitized images as most popular software can cope with it. See also JPEG.

gigabyte (Gb)
1024 megabytes or one thousand million bytes.

grammar checker
part of a word-processing application which scans through text on the screen and highlights any word or group of words where the grammar may need correcting. The user is given the options of ignoring or correcting the text. See also spellchecker

graph–plotting software
software which allows the user to create graphs from equations. Equations can be entered with parameters using familiar notation such as y = x² – 4. Many versions offer much more than this, for example, gradient functions, scatter diagrams, and a dynamic approach to transformation geometry.

graphical user interface (GUI)
screen representation of the computer’s control system, enabling the user to move an on-screen cursor, usually with a mouse, and ‘click’ on pictorial representations or icons in order to make the computer perform various instructions. Mouse movements usually have keyboard alternatives.

charts, diagrams, pictures, symbols or animations on a computer screen which may be printed out or saved to disk.

graphics card
circuit board that controls the screen representation of images.

graphics tablet
device that enables the mouse to be replace by a pen. The pen replaces all of the mouse functions.

computer technologies used to support group interaction. Examples include conferencing (audio, graphics and video), electronic mail, computer conferencing, scheduling and diary management systems, shared desktop systems and multi-user editors.

GUI see graphical user interface


hard copy
printed output from a computer as opposed to the ‘soft’ copy stored on the computer.

hard disk
computer storage medium, rigid disk usually made from aluminium, coated with magnetic material and hermetically sealed, fitted internally in a personal computer. See also CD-ROM, floppy disk.

physical components of a computer or a communications system, including both mechanical and electronic parts, such as the processor, hard drive, keyboard, screen, cables, mouse and printer. Contrasted with software.

hardware compatibility
computers which can use the same software because they share or can use the same operating system.

home page
opening or main page of a web site of a particular organization or individual.

computer acting as an information or communications server; often used for a computer acting as a web server.

hotlink see hyperlink

user-created list of addresses (URLs) of world wide web sites or pages to allow easy revisiting. Netscape calls this ‘bookmarks’, Microsoft Internet Explorer uses the term ‘favourites’ and ANT Fresco uses ‘hotlists’.

organizing and pruning information and software on a computer to keep them manageable and minimize the storage space they occupy.

HTML see hypertext mark-up language

http see hypertext transfer protocol

in a hypertext document such as a world wide web page, the predetermined area (which can be a word or set of words, an image or part of an image) which can be clicked on to jump to other documents, or other parts of the same document.

conceptual term for the use of hypertext links to connect multimedia items.

system enabling the non-sequential connection of information, linking one computer file with another or part of another. The user can choose to follow the link or to continue using the original file sequentially. Used for the world wide web. See also hyperlink, hypertext mark-up language.

hypertext mark-up language (HTML)
computer language used to create hypertext documents such as world wide web pages. The author using HTML ‘marks up’ or defines how elements of the text will appear on the web by inserting ‘tags’ which will be invisible to the ordinary user of that page. The tags are special instructions to the computer, such as to insert a picture or to change text size and style. Tags may also define text or an image as a link to another page (a hyperlink). Text editors or word-processing packages can be used to create HTML documents, and it is useful to know how to create and edit ‘raw’ HTML, but there are also many specially designed packages enabling easy HTML creation.

hypertext transfer protocol (http)
standard for the process of requesting and transferring a page on the world wide web. For the transfer to succeed, the page must have been constructed as a hypertext document using the hypertext mark-up language.


I beam
form the cursor takes when text is being edited.

in a graphical user interface, a small symbol or picture on the computer screen, for example representing a software package or a data file. The user clicks on the icon to start the package or open the file.

ICT see information and communications technology

ILS see integrated learning system

information and communications technology (ICT)
application of modern communications and computing technologies to the creation, management and use of information.

information superhighway
usually used to mean a broadband network capable of transferring very large amounts of information, including video, still images, audio and text, at high speed between remote users. See also internet

information technology (IT) see information and communications technology

input device
device which is capable of writing information to a computer system, such as a keyboard, mouse, touch screen, sensor, scanner or microphone.

to copy all the files of a software package on to a computer and make any changes needed to existing files so that the software then works. Installation or set-up programs do this for users.

integrated learning system (ILS)
computer-based system with a diagnostic capability that monitors and manages the delivery of curriculum material to students so that they are presented with individual programmes of work.

integrated package
software package, a suite of applications which have a consistent interface and include a word-processor, spreadsheet and database, bundled together. Other software may be included, such as graphics and communication modules. Data can be transferred easily between the applications.

Integrated Services Digital Network (ISDN)
telecommunications standard for the transmission of digital information over ordinary telephone lines, and the name for the digital telephone network. Contains channels for digitized speech, data, image or video signals.

intelligent tutor package
instructional package that responds to the learner’s inputs to the computer, channelling the learner from activity to activity according to responses made. Such packages may have an explicit didactic element or may be designed in a more exploratory or collaborative mode.

interactive video (IV)
computer linked by software to a video system which allows the user to control a video disk and explore the information on that disk; choices can be made about the order in which the exploration takes place.

equipment or software which enables a user to communicate with the ‘raw’ system they are accessing, for example, a menu or icons on a screen (see graphical user interface). Also any join between items of hardware or software, such as connections with printers. For a peripheral device such as a printer to communicate with the main computer, their interfaces must be compatible.

also known as the ‘net’, the inter-communicating computer networks which host and provide access to the world wide web, file transfer, e-mail, news and other services.

internet protocol (IP)
set of communication standards which control activity on the internet. An IP address is the number assigned to any computer connected to the internet, and is the only way in which information sent through the internet can find its way to that computer. It is a number of the form A.B.C.D where each letter represents a number from 0 to 255, e.g. See also domain name system.

internet relay chat (IRC)
method of ensuring ‘real-time’ and multi-user communication. When internet users are on line simultaneously, they can communicate by sending text messages which are read almost as quickly as they are sent – i.e., on a par with normal face-to-face conversation.

internet service provider (ISP)
organization with a direct connection to the internet acting as an intermediary for other users, providing them with an e-mail address and software, access to the world wide web, and often space on web servers for home pages etc.

internal web site set up to serve a closed group such as a school, which contains pertinent information such as school documents, bulletin boards, health and safety information etc.

IP see internet protocol

ISDN see Integrated Services Digital Network

ISP see internet service provider

IT see information and communications technology


programming language designed to add interactivity and functionality to the web by enabling developers to write and distribute programs that would run on any computer regardless of the operating system.

joystick (games stick)
input device with a stick which can move left, right, forwards and backwards to control the movement of a pointer on screen. The stick has a press switch which has the same action as the ‘select’ button on a mouse.

acronym for ‘Joint Photographic Experts Group’, JPEG is an image-compression format which reduces the storage space the file takes up.


kilo-bit, kilobyte.

unit of measurement of data transfer speed, 1024 bits per second.

particularly associated with ‘free-text’ databases, an important word within text which is marked to ease retrieval. A search using a keyword will display each individual record containing it.

emulator device attached to the computer which enables switch users to use standard software. A grid of numbers, letters and symbols represents the standard keyboard. The user selects the characters required by scanning the device with the switches and the information is sent to the computer. See also assistive technology.

keyboard overlay see overlay keyboard

rigid frame placed over the keyboard. It is raised above the keys and has holes in it to allow access to the individual keys through the holes. With a keyguard, users with poor fine motor skills may access the keyboard more accurately. An overlay keyguard works in the same way for use with an overlay keyboard. See also assistive technology.

input device which has letters, numbers or symbols on it, like a small keyboard. Numeric keypads allow only numbers to be entered.

kilobyte (k)
unit of measurement of storage capacity, 1024 bytes, or one thousand.


LAN see local area network

laptop computer
portable computer, small enough to carry around and use on a lap.

laser disk see video disk

LCD see liquid crystal display

leased line
permanent connection over the telephone network to, for example, a PoP. Telephone charges are per line rather than per call made. Therefore, regardless of use, the costs are fixed and predictable.

liquid crystal display
thin flat screen used in portable computers, digital cameras and watches where space is at a premium.

link see hyperlink

automated e-mail distribution system, one method of supporting discussion groups using e-mail. The list is of e-mail addresses of everyone who has joined the group (known as subscribers). A message posted to the group is sent to the listserver which copies the message to every subscriber on its list. Each subscriber finds a copy of all the new messages from the group waiting in the mail. Also sometimes known as a ‘mailing list’. Many such lists are relevant to and subscribed to by teachers, such as SENCo forum, and many also make their archives available to non-subscribers via the web.

local area network (LAN)
communications system linking computers within a restricted geographical area such as a building or campus. This also allows computers to share information from a central source.

simple programming language which allows the user to give instructions to a computer in ordinary language – words and numbers rather than codes. In its simplest form (turtle graphics) it allows the user to control the movements of a screen turtle.


often-repeated sequence of actions which can be defined and named by the user of some applications software so that they can set the sequence going in one step by calling the macro up by name. Sometimes a macro can be programmed by example, storing the user’s actions as they occur.

one million bits per second.

megabyte (Mb)
1024 kilobytes or one million bytes.

megahertz see clock speed

used in contradictory ways by those familiar with computers, so a term to be wary of. Logically one of its meanings encompasses all the areas used by a computer to store information, including the long-term storage area used by computer systems to hold programs and information files (on a personal computer, the hard drive). However, its meaning is sometimes restricted to the ‘random access memory’ (RAM), which is the computer’s temporary working store, usually a single chip which can hold very large amounts of data and manipulate it very quickly, but will not retain it when the power supply is switched off – for that, it must be saved to the hard disk. The user can record things in both the above forms of memory. However, some forms of storage are ‘read-only’ (ROM), with information which has been recorded during manufacture and cannot then be altered, added to or erased, e.g. CD-ROMs.

list of options from which a user can select in order, for instance, to start a program or open a file.

MHz see clock speed

computer environment which enables the learner to focus on a particular area of mathematics.

midi see musical instrument digital interface

MIME (multipurpose internet mail extensions)
messaging standard for e-mail attachments on the internet.

mini keyboard
reduced-size keyboard with small buttons to represent the keys. Can be useful for those with limited finger movement.

in computing, a representation of a real or imagined situation governed by certain rules which are managed by a computer program. The rules or data can be changed by the user and the outcome of the changes viewed on the computer screen.

modem (modulator-demodulator)
device which translates digital signals into audio signals (and vice versa) so that data can be carried over ordinary telephone lines. Modems operate at different speeds depending on the model.

screen used with a computer, also known as a VDU (visual display unit) or DSE (display screen equipment).

main printed circuit board (PCB) in the computer, which holds the principal components. The processor and clock chips will either be plugged into or soldered to the motherboard. See also central processing unit.

small moulded plastic box with clickable buttons on top and a rolling ball or optical ‘reader’ underneath, moved by hand across a flat surface to control the screen cursor position. It enables the user to access menus and to select and move words or other objects around the screen. Alternatives to the mouse include touch screens and trackballs.

mouse pen
input device shaped like a thick pen and with a ball on the end. It behaves in the same way as a mouse when run over a flat, soft surface.

acronym for ‘Moving Photographic Experts Group’, an international standard for storing digitized video in compressed form.


mud (multi-user dungeon/dialogue/dimension)
interactive games environment allowing role play (often on the internet).

combination of moving images, graphics, text and sound. A multimedia machine is fitted with hardware such as sound and video cards and a CD-ROM drive, and may include peripherals such as a camera, microphone and scanner.

musical instrument digital interface (midi)
device which allows the interchange of signals between a computer and any musical device fitted with midi such as a music synthesizer.


National Grid for Learning (NGFL)
government initiative intended to connect all schools, colleges and universities to the internet, provide them with information and resources and prepare them for interconnectivity.

net see internet

etiquette on the internet, found in codes of conduct drawn up by users to stop abuses and abusive behaviour.

electronic communications system linking computers, computer systems and peripherals such as file servers and printers.

newsgroup see Usenet

type of laptop compute, lighter and thinner than earlier models.


object linking or embedding see embed

on-line database
remote database which can be accessed over a network or via the internet.

on-line service
service, often but not always an e-mail or database service, which is accessed remotely via telecommunications links.

On-line Public Access Catalogue, in other words, an electronic library catalogue.

operating system (OS)
program or set of programs which controls the computer. Different types of computer use different operating systems, including MS-DOS, Windows 95 and successors, Risc-OS, and MacOS.

optical character recognition (OCR)
method of scanning where a light source and photo cell recognize patterns of dark and light on a sheet and with appropriate pattern-matching software can convert text on paper to computer-held digitized text.

optical head pointer
input device which allows the user to control the computer with a pointer attached to a headband. See also assistive technology.

optical mark reader (OMR)
scanner which can detect straight marks in given places on a sheet, for example, a completed multiple choice test or lottery ticket, and convert them to computer-held data.

overlay keyboard
flat, touch-sensitive membrane on which paper overlays containing words, pictures or objects can be placed. The keyboard is used as a replacement or accompaniment to the conventional keyboard for users with letter recognition or physical difficulties. The keyboard consists of individual cells, which can be programmed individually or in groups to perform a particular task or display specific text on the computer screen. See also assistive technology.


software suite designed for a particular application or job, such as word processing or accounts.

packet switching
data transmission method that breaks down a flow of data into smaller units called packets. These are individually addressed and routed through a network. Technologically developed countries have at least one publicly available packet-switching network.

palmtop computer
portable pocket-sized computer with a screen in a folding lid. The keyboard is very small and the screen less than half the size of those on laptop computers.

PC see personal computer

PDF see portable document format

Intel’s successor to the 486 processor. Initially called a P5 and later referred to as a Pentium because it was the fifth in the 80X86 sequence of microprocessors. It would have been called an 80586 had it not become illegal in the United States to register a number as a trademark. See also central processing unit.

hardware device which can be plugged into the computer to perform some additional function such as a disk drive, a printer, an overlay keyboard or VDU.

Perkins Brailler
machine for producing Braille.

personal computer (PC)
computer designed for individual users rather than several users at any one time. Usually taken to mean an IBM or IBM-compatible machine.

smallest point in a screen image. See also resolution.

output device which draws on paper or film with pens, usually to produce graphics.

optional additional features which can be added to a software package.

point to point
data channel which connects two, and only two, terminals.

PoP (point of presence)
location and telephone number provided by an internet service provider (ISP) for local dial-up access to the internet by users. The more PoPs in the country, the more likely you are to pay local call rates. (Do not confuse with POP, which stands for Post Office Protocol.)

POP (Post Office Protocol)
POP2 and POP3 are e-mail standards.

interface between the central processing unit and any peripheral devices.

portable computer
generic term covering all personal computers which are light enough to carry with one hand, such as laptops, notebooks and palmtops.

portable document format (PDF)
used to store and transmit text and images with a set appearance, sometimes in order that documents appear exactly as in print with the same line endings and pagination. PDF files can be created and read using software such as Adobe Acrobat.

predictive typing utility
software which anticipate the completion of words as text is entered into the computer (see also fuzzy matching). Useful for those who have difficulty with typing or spelling. Sometimes called predictive word processor.

device used to produce hard copy (paper copy) from a computer. Various types are available: a dot matrix printer produces output by firing pins against an inked ribbon; bubble or inkjet printers squirt or squeeze ink through pins, and a laser printer works in a similar way to a photocopier.

ordered and structured commands to perform a particular task. For example, a Logo procedure for turning two lights on and off in order might be: TURNON 1 WAIT 10 TURNOFF 1 WAIT 10 TURNON 2 WAIT 10 TURNOFF 2.

processor see central processing unit

in this American spelling, standard term for the set of instructions carried out in sequence by a computer to perform a given task. Programs are written in English-like programming languages and are then translated into binary code by an intermediary program called a compiler. Large software systems are normally sets of several programs.

programmable toys
toys which will obey a sequence of computer instructions – for example, floor turtles.

programming language
artificial language constructed to enable the user to communicate with a computer and to create programs for it to run. Examples of programming languages used in school are Logo and BASIC.

rules or procedures usually set out in an agreed international standard (e.g., file transfer protocol) governing how communications are handled by a network of computers.

public domain software
freely available and distributable software, also known as freeware. It is free of copyright and should not be confused with shareware.


QWERTY keyboard
standard computer keyboard with keys laid out in the same order as a traditional typewriter. The first six keys in the top left-hand corner spell QWERTY. The keyboard was so arranged to slow typing down because keys would jam if hit in quick succession.


RAM see memory

random access memory see memory

read-only memory see memory

real-time video
display of moving pictures on a computer screen as they happen. For example, a television broadcast can also be broadcast on the internet. The pictures will be displayed as they arrive at the computer, instead of all being stored in a file first. Two-way real-time video is used in video conferencing. The recipient can see and hear the sender as they speak and can reply in the same way at the same time.

clarity and sharpness of pictures and text as they appear on the screen or on paper, often measured in dots per inch (dpi). The greater the dpi, the better the resolution. Screen resolution is measured by the number of pixels in a row and the number of rows and columns, together with the size of the pixel on the screen. The larger the screen, the higher the resolution should be.

‘calling back’ stored data into the computer’s working memory. Also used for rescuing data which has been erased or corrupted.

mechanical device which can be programmed by the user to follow a sequence of commands.

ROM see memory

root directory see directory

communications device that chooses the route by which information should travel through a network.


device by which hard-copy pictures and text can be converted into digital form for use on a computer. Small hand-held devices work by rolling the scanner head across the paper. Larger flatbed scanners work rather like a portable photocopying machine. With a speech synthesizer, it is possible to scan text into the computer and hear it read aloud. Can also be used to read bar codes and convert them into numeric data.

screen resolution see resolution

screen saver
facility to switch a computer screen off or alter the display if the keyboard or mouse has not been used for a while. This is to prevent the current image from being etched into the screen if it is left on for an extended period.

screen turtle
in Logo, representation of the floor turtle displayed on a computer screen. The screen turtle can be shaped like an arrow head, a turtle or other user-defined shape. Also described in national curriculum documents as a ‘screen image’.

to move up and down or from side to side through a document or window to view or access its contents.

acronym for ‘small computer systems interface’, an internationally defined standard interface for connecting peripheral devices to a computer.

search engine
software, often found on web sites, which searches for information on the world wide web or text-based databases.

one of a range of sensors which can measure a parameter such as light level, sound level, pH, position or temperature and convert the value to a voltage level. That is then passed to the computer where it is interpreted as a number.

computer system that provides a particular service to devices on a network. In the context of the client–server model, a server is the software on a remote computer servicing a client with the resources the client requests. In a local network, a file server holds system software on its hard disk, and is usually the most powerful machine in the system. A network may have a number of file servers storing data of a particular type. Network users can access their own files remotely and interchange information with these central stores.

Software that is freely available but developers will ask for fees and depend on the user’s honesty for payment. Not to be confused with public domain software or freeware.

silicon chip see chip

in computing, pre-defined but dynamic model of a situation which allows the user to pretend to do things that might be impractical or dangerous in real life. This could be motor racing at Silverstone or heart surgery. There are also decision-making simulations such as moving house.

small software
relatively small programs or specially prepared collections of files in an application written for a particular purpose, to cover a focused part of the curriculum. Examples would be spreadsheet files available from the internet, exploration of aspects of probability and statistics, etc.

Braille output provided by a computer attachment which uses small pins to produce Braille characters.

generic term for all computer programs. Software falls into two major types: applications such as spreadsheets or databases, and systems software such as MS-DOS or Windows. In addition, there are utilities or tools. Contrasted with hardware. See also compatibility, upgrade.

sound card
printed circuit board that can be plugged into a slot in the motherboard of a computer to expand its capabilities and allow sound output. Sometimes referred to as a sound board.

sound board see sound card

speech synthesizer
device with accompanying software used with a computer to ‘speak’ text by selecting elements from stored sounds or by breaking down the text into individual elements (phonemes) which are then produced in the correct sequence. See also augmentative and alternative communication, synthesized speech.

electronic dictionary, usually part of a word-processing application, which scans text on the screen and highlights any word it does not recognize. The writer is given the option to correct, ignore or add the word to the dictionary. The spellchecker can be set to offer alternative spellings to the writer. See also grammar checker.

computer program which allows words and figures to be entered into individually identifiable cells on a grid format. Cells can be linked by formulae, so that altering numbers in individual cells will produce an alternative set of results. Spreadsheets may be used to model situations whose rules are governed by mathematical relationships such as numerical series like Fibonacci or the management of a budget account, and have been extended to act as simple databases and word-processors.

standard keyboard see querty keyboard

popular term for exploring the world wide web.

input device which at any time can be either on or off. Where a user’s physical movement is impaired, switches may be required to operate the computer. Many switches have been designed to meet the particular needs of disabled people. See also assistive technology.

switch interface box
box with sockets into which switches can be connected which can in turn be attached to a computer.

synthesized speech
electronic speech produced by a computer or speech synthesiser from text rather than from a real voice. The vocabulary that can be spoken is not limited to the available memory (as with digitized speech), but the accuracy and clarity of the speech may be affected, as the computer pronounces speech according to a set of rules stored inside the machine. Often the spelling of a word can be adjusted to improve its pronunciation.

systems software see software

system unit
usually taken to mean the box housing the central processing unit, the motherboard, expansion slots, hard disk and internal disk drives, etc., apart from the keyboard, mouse, screen and printer. May be referred to as the central processing unit.


formatting code used in hypertext mark-up language (HTML).

acronym for ‘transmission control protocol/internet protocol’, the standard set of rules ensuring the proper transfer of information on the internet.

acronym for ‘tagged image file format’, a graphic format developed by Aldus and Microsoft.

transmission of information over distance using telephone lines, cables or satellite signals to send and receive images, sounds and words.

using telephone and computer links to connect people in a meeting who are in different locations. Also known as audio-conferencing or video-conferencing if live (real-time) pictures are involved.

combining information and communications technologies and services.

ordered and structured system for displaying a limited number of information screens on a video or television monitor adapted to interpret such information which is sent with transmitted programmes as a narrow set of data at the top of the picture. The two best-known systems are those used by the BBC (Ceefax) and commercial companies (Teletext, previously Oracle). These systems allow the user to make limited choices about the order in which they view the screens.

strictly speaking, transmission of handwriting in real time from one system to another. More generally, the term is used to describe a system which offers not just the transmission of handwriting but also other features such as the transmission of pre-stored graphics in a graphical shared-screen environment. Telewriting often appears as a component of other systems.

terminal adapter
interface equipment between a computer and an ISDN line (the equivalent of a modem).

component at the end of a cable segment.

text file
file of plain, unformatted text composed of ASCII characters.

text manipulation program
term embracing software which allows the manipulation, storage, retrieval and printing of words, graphics and images. Also used for programs for language learners where the tutor inputs the text and the computer creates activities including Cloze, gap-filling, re-ordering etc.

touch screen
display screen which enables the computer to react to the touch of a finger or stylus.

track pad
touch-sensitive pad used to control the cursor, often found on laptop computers.

device used to control the cursor. The user moves the ball which in turn moves the pointer on the screen. Selections are made by pressing the buttons on the device, and this is especially suited to users who find small hand movements difficult.

turtle graphics
diagrams drawn by a screen turtle controlled using Logo or a Logo-like program. It is also called ‘turtle geometry’ since it allows the user to explore shape, space and angle of turn.


use of a program to remove unwanted software from a computer.

new version of a piece of software which is made available to registered users of an earlier version at a lower price than is charged to new users. Usually identified by a later version number – e.g., 1.1, 1.2, 1.3, show updates on version 1.0, whereas 2.0 would signify a major upgrade.

to transfer data from a small computer (such as a personal computer) to a larger or main one. The opposite of download. Also the transfer of data from a storage medium to a computer.

URL (Uniform Resource Locator)
unique reference locating a file on the world wide web and other internet resources – the Learning Schools Programme URL, for instance, is: http://www.learningschools.net. See also domain name system.

universal serial bus connector. Standard for connecting peripherals such as scanners and printer to personal computers simply and quickly.

largest and oldest distributed bulletin board on the internet, with over 20 million users. Users join groups (‘newsgroups’) to discuss specific topics, from astronomy and medicine to astrology and cat breeding. The Usenet has its own code of conduct (acceptable use policy or AUP), vocabulary (e.g. ‘spamming’ for posting advertising and ‘flaming’ for angry or abusive messages), and acronyms for common expressions (e.g. FYI – for your information, IMHO – in my humble/honest opinion).

user group
people who get together to discuss a particular product or technology. Each of the main computer manufacturers has one or more associated user groups.

software, usually small, which is designed to perform a single routine task, either on whole files, such as copying, deleting and sorting files, or as an extra bolt-on which extends the capacity of an applications package. See also software.


VDU see monitor

video disk
also known as ‘laser disk’, analog storage medium, a large disk like a long-playing record. Not to be confused with ‘digital video disk’ – see digital versatile disk.

virtual reality (VR)
simulation of an environment by presentation of three-dimensional and moving images and an appropriate soundtrack, giving the user the impression of being able to move around within the environment. Users can experience tactility etc. with the use of sensors, gloves and/or helmets.

mischievous or destructive software transferred covertly to files and applications, often via the internet or with other files on a disk. Some can disable a computer or network once activated and must, if possible, be removed using anti-virus software. There are, however, many hoax virus warnings and users should not pass on such warnings unless they are sure of their reliability.


W3C see World Wide Web Consortium

WAN see wide area network

web address see URL

web browser see browser

web page
file created in hypertext mark-up language and displayed on the world wide web.

web site
area on a server linked to the internet which is devoted to one organization or individual’s web pages.

wide area network
in contrast to a local area network, which links computers at the same site, a network which links computers over a large geographical area, including telecommunication links such as satellites.

originally the graphical user interface (GUI) between applications and the operating system developed by Microsoft for IBM-compatible personal computers, and from Windows 95 on, the operating system and interface combined.

wild card
symbol used in command or search instructions to stand for a range of characters. Thus, a question mark is used to stand for ‘any single character’, while an asterisk is used to mean any character or group of characters or none.

on-screen step-by-step guide that helps a user perform a particular task.

software originally devoted to the creation, editing, formatting, storage, revision and printing of text, but currently often including the capacity to include graphs, spreadsheets, and photographs, and to produce sophisticated page-layouts.

world wide web (WWW)
also known as the WWW, W3 or simply the web, a distributed information service on the internet of linked hypertext documents accessed using a web browser such as Microsoft Internet Explorer or Netscape. On the web, any document can be linked to any other document.

World Wide Web Consortium (W3C)
international non-profit organization devoted to developing the potential of the world wide web. Activities include setting standards and common frameworks in this rapidly evolving field, including an accessibility initiative.

WORM (write once read many)
computer storage medium, optical disks on which information can not be erased or amended once it has been recorded.

write protect
to protect a disk or file so that its contents cannot normally be altered or erased, usually by moving a notch on the disk casing, or amending the files properties.

WWW see world wide web

WYSIWYG (what you see is what you get)
accurate representation on the screen of the appearance of the final output.


to compress files to reduce the storage space they occupy.

zip disk
high capacity disk, capable of storing 100Mb of information on sturdy pocket-size disks.