Glossary
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
A
accessibility
major consideration for choice of educational software and hardware. Barriers
to access can include, for example, equipment that relies heavily on fine
motor skills, on conveying information only by visual means, or systems assuming
too high a level of literacy or technical skill. See also augmentative and
alternative communication and assistive technology.
address, world wide web, see uniform resource locator
address book
in e-mail, list of regular contacts’ addresses held in the e-mail software.
adventure game
computer-based game which allows the exploration of a scenario or story in
which the player is an ‘adventurer’. Adventure programs used to
be in text form only, often with long narrative descriptions, but they have
now incorporated graphics. Some adventure games have graphics only. The user
is encouraged to make decisions based on a limited set of rules or options
predetermined by the author of the program. The outcome of the game depends
on the decisions made.
agent
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.
analog
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
anchor
on the world wide web, the target of a hyperlink, a clickable link between
documents or files or between places within a document or file. Anchor and
links are created using a programming language called hypertext mark-up language.
anti-virus software see virus
animation
display of a sequence of images to give the impression of movement. Simple
animation programs are available.
applet
pre-written, mini-programs (sub-routines) used on a web page to operate a
specific function. For example, an applet might be used to make part of a
text wiggle while various colours flow through it. (From ‘application’.)
application see software
archive
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.
ASCII
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.
assistive technology
use of technology, including computers, to render the environment accessible
to users who have learning difficulties, limited mobility or sensory impairment,
e.g. switches, voice recognition programs, overlay keyboards, etc.
attachment
file which is attached (linked) to and sent with an e-mail message.
augmentative and alternative communication (AAC)
for users who have limitations on their ability to communicate using natural
speech, the use of technology, including computers, to assist or replace speech,
such as voice boxes or speech synthesizers.
AUP see Usenet
authoring software
programs which help relatively inexperienced users create multimedia or hypertext
documents.
B
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.
bandwidth
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; narrowband networks tend to be
text-only and are slower. For example, voice over the telephone network requires
a bandwidth of 3 kHz, while uncompressed video requires a bandwidth of 6 MHz.
bar code
arrangement of vertical lines of varying thickness with spaces in between.
The spacing and line thickness represent a numeric code used to enable a computer
to identify the item. A scanner is used to read the code.
BASIC (Beginners’ All-purpose Symbolic Instruction Code)
one of the easiest languages for writing programs (see programming language).
Many operating systems come supplied with a version of BASIC.
baud
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. See also bits per second,
characters per second.
bit
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.
bitmap
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).
bookmark see hotlist
Boolean operator
also known as ‘logical operator’, word or symbol which defines a
logical relationship between two data items. This relationship can be ‘AND’,
‘OR’ or ‘NOT’. For example, searching a database can be
made more efficient by using Boolean operators with the search terms, so that
only terms which occur together are retrieved (using AND) and others are excluded
(using NOT).
boot
to start up a computer. The computer is regarded as ‘bootstrapping’
itself by loading the program which starts its operating system.
bps see bits per second
Braille notebook
portable computer in which the user keys in Braille, the system of representing
letters with raised dots to allow reading by touch. The output can be printed
either as Braille or in regular text format.
broadband
informally used to mean ‘faster than common networks’, and so the
actual meaning depends on what is common at the time. Currently broadband
is regarded as starting at 34 Mbit/sec (Mbps) – under this classification,
all commonly occurring local area networks (such as Ethernet) are narrowband.
browser
software used to search and retrieve information from the world wide web.
Netscape, Microsoft Internet Explorer and ANT Fresco are browsers.
bug
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. Information posted by users can
be stored and displayed and, sometimes, software downloaded. See also listserver,
Usenet.
byte
unit of information equal to eight bits. Usually, each byte stores one character.
C
cache
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. CAM is a general term for computer support during the manufacturing
process.
card
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.
calculator-based ranger (CBR), calculator-based laboratory (CBL)
versions of data logging devices that connect directly to a graphic calculator.
The CBR collects motion data. The CBL comes with probes that can collect voltage,
light and temperature data.
CD-ROM (compact disk read-only memory) c
omputer storage medium, optical disk which physically which resembles a 12
cm audio CD but contains a range of data types stored digitally, such as words,
graphics and sound rather than simply sound. CD-ROMs can store up to 250,000
pages of text with a capacity of 650Mb. Once written, the disk cannot be altered,
hence ‘read-only’. See also floppy disk, hard drive.
CD writer (compact disk writer)
hardware device which can save information on to a CD.
central processing unit
generally used to mean the microprocessor, the integrated circuit which is
the controlling core of a personal computer, usually situated in the box with
the hard disk. Sometimes used to refer to the box and its contents.
chip
popular name for an integrated circuit, also called a ‘silicon chip’
as all the circuitry is etched on to a thin slice of silicon.
client
program or computer which asks for services from a server (a resource-providing
computer).
clip art
library of copiable pictures (usually copyright-free) stored on computer disk,
CD-ROM or web site, useful for importing into art, multimedia or desktop-published
files.
clipboard
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.
clock speed
speed of a microprocessor expressed in megahertz (MHz) (millions of cycles
per second) representing the number of instructions the computer can carry
out each second.
CMC see computer-mediated communications
comm port
hardware link (socket) into which cables can be plugged so that a computer
can communicate with printers, modems, other computers etc.
comms
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.
communication aid see augmentative and alternative communication
compatibility
pieces of equipment and/or software which are capable of being used together
without special modification or adaptation are termed ‘compatible’.
compression
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 conferencing
development of electronic mail designed to support many-to-many communication.
Each conference consists of a group of users who have a common interest in
the conference subject matter. Computer conferencing software enables organization,
storage, structuring and retrieval of messages. In particular, messages may
be organized under different topics, by author or by date of posting. See
also listserver, Usenet.
computer-mediated communications (CMC)
use of computers to communicate, as in computer conferencing and electronic
mail.
computer program see program
concept keyboard
particular make of overlay keyboard.
conferencing see computer conferencing, tele-conferencing or video conferencing
content-free program
software providing a framework and all necessary tools and utilities for the
user, but which of itself contain no data until the user enters their own.
Can be used to produce a range of products.
convergence
term applied to the way in which computing, telecommunications and, more recently,
television are moving towards a common technological basis characterized by
the use of digital systems.
cookie
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.
copy, cut and paste
techniques of duplicating or removing data from one place and inserting it
elsewhere. See also clipboard.
courseware
computer-based instructional material, e.g. lecture notes, tutorials, tests,
etc.
CPU see central processing unit
crash
sudden failure of software or hardware, often resulting in no response to
mouse or keyboard actions.
cursor
screen representation of a pointer which responds to mouse or keyboard movements.
cyberspace
popular term for the internet, coined by William Gibson in his novel Necromancer,
published in 1984.
D
data
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.
database
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.
default
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.
dial-up
connection to the internet or another computer over an ordinary telephone
line.
digital
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
directory
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.
download
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
drag
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
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.
embed
to insert information stored in one format into information in another format,
for example a graphic into a text file.
embosser
special type of printer that can produce Braille from a computer.
emulator
hardware or software which enables one type of computer to behave like another.
encryption
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
F
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.
field
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’.
file
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.
firewall
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.
freeware
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.
G
gateway
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.
graphics
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.
groupware
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
H
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.
hardware
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.
host
computer acting as an information or communications server; often used for
a computer acting as a web server.
hotlink see hyperlink
hotlist
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’.
housekeeping
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
hyperlink
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.
hypermedia
conceptual term for the use of hypertext links to connect multimedia items.
hypertext
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
I beam
form the cursor takes when text is being edited.
icon
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.
install
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.
interface
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.
internet
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. 193.63.56.222. 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.
intranet
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
J
Java
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.
JPEG
acronym for ‘Joint Photographic Experts Group’, JPEG is an image-compression
format which reduces the storage space the file takes up.
K
kb
kilo-bit, kilobyte.
kbits/sec
unit of measurement of data transfer speed, 1024 bits per second.
keyword
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.
keyboard
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
keyguard
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.
keypad
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.
L
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
listserver
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.
Logo
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.
M
macro
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.
Mbits/sec
one million bits per second.
megabyte (Mb)
1024 kilobytes or one million bytes.
megahertz see clock speed
memory
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.
menu
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
microworlds
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.
model
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.
monitor
screen used with a computer, also known as a VDU (visual display unit) or
DSE (display screen equipment).
motherboard
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.
mouse
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.
MPEG
acronym for ‘Moving Photographic Experts Group’, an international
standard for storing digitized video in compressed form.
MS-DOS see DOS
mud (multi-user dungeon/dialogue/dimension)
interactive games environment allowing role play (often on the internet).
multimedia
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.
N
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
netiquette
etiquette on the internet, found in codes of conduct drawn up by users to
stop abuses and abusive behaviour.
network
electronic communications system linking computers, computer systems and peripherals
such as file servers and printers.
newsgroup see Usenet
notebook
type of laptop compute, lighter and thinner than earlier models.
O
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.
OPAC
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.
P
package
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
Pentium
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.
peripheral
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.
pixel
smallest point in a screen image. See also resolution.
plotter
output device which draws on paper or film with pens, usually to produce graphics.
plug-ins
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.
port
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.
printer
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.
procedure
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
program
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.
protocol
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.
Q
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.
R
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.
resolution
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.
retrieval
‘calling back’ stored data into the computer’s working memory.
Also used for rescuing data which has been erased or corrupted.
robot
mechanical device which can be programmed by the user to follow a sequence
of commands.
ROM see memory
root directory see directory
router
communications device that chooses the route by which information should travel
through a network.
S
scanner
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’.
scroll
to move up and down or from side to side through a document or window to view
or access its contents.
SCSI
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.
sensor
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.
server
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.
shareware
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
simulation
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.
softbraille
Braille output provided by a computer attachment which uses small pins to
produce Braille characters.
software
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.
spellchecker
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.
spreadsheet
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
surf
popular term for exploring the world wide web.
switch
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.
T
tag
formatting code used in hypertext mark-up language (HTML).
TCP/IP
acronym for ‘transmission control protocol/internet protocol’, the
standard set of rules ensuring the proper transfer of information on the internet.
TIFF
acronym for ‘tagged image file format’, a graphic format developed
by Aldus and Microsoft.
telecommunications
transmission of information over distance using telephone lines, cables or
satellite signals to send and receive images, sounds and words.
tele-conferencing
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.
telematics
combining information and communications technologies and services.
teletext
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.
telewriting
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).
terminator
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.
trackball
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.
U
uninstall
use of a program to remove unwanted software from a computer.
upgrade
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.
upload
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.
USB
universal serial bus connector. Standard for connecting peripherals such as
scanners and printer to personal computers simply and quickly.
Usenet
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.
utility
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.
V
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.
virus
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.
W
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.
Windows
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.
wizard
on-screen step-by-step guide that helps a user perform a particular task.
word-processor
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.
Z
zip
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.