CIE ICT IGCSE THEORY/PRACTICAL GLOSSARY

central processing unit

The part of the computer that interprets and executes commands from computer hardware and software.

administrator

The person who is in control of a computer network.

authentication

The process of determining whether someone is in fact who they claim to be; the most common form of authentication is user IDs and passwords, but there are others (e.g. biometric data).

aspect ratio

The proportion of length to width of an image. Maintaining the aspect ratio means to keep the original proportion of the image (without distortion) and is usually needed when images are resized.

body

The section of HTML in a webpage that contains the contents (e.g. text, images, etc) and the tags describing the content, hyperlinks and structure (e.g. tables used to lay out the page) of a webpage.

bandwidth

This is a reference to the range of frequencies a communication channel can handle. The bigger the bandwidth the more data can be sent and received at the same time. The amount of data that can be communicated also relies upon the transfer rate. This is often used to describe Internet connection, with the term broadband meaning it has more than 3KHz (although in real terms at least 300MHz is needed in current systems).

cathode ray tube monitor

An older type of monitor that has an electron beam directed towards a screen coated in phosphors which glow when hit by the beam. Screens are refreshed 25 times a second.

ascender

The part of a lowercase letter (b, d, f, h, k, l or t), that extends above the body of the letters.

CAD software

See computer-aided design software

.rtf

See rich text format

.txt

See text file

browser

See web browser

.zip

See zip

bit

Short for binary digit and equal to a 1 or a 0; the fundamental memory unit.

blogs

Short for web log; a webpage which is accessed by the public, who can read or write messages.

anti-virus

Software that detects and removes/ isolates computer viruses.

anti-spyware

Software that detects and removes/isolates spyware.

applications software

Software that enables a user to carry out a specific function on a computer e.g. spreadsheet, word processor, database, etc.

back up

A copy of a file/data on a different medium (e.g. disk, flash drive, CD, etc.) in case of problems with the internal hard disk drive.

analogue to digital converter (ADC)

A device used to convert analogue signals (usually from sensors) into digital signals which can then be understood and processed by a computer.

analogue device

A device/apparatus that measures information that is continuously changing (analogue data), e.g. an analogue sensor.

attachment

A document/file sent with an email which requires the recipient to open it to read/ see/listen to the contents.

alphanumeric

A field type where any character is acceptable input - sometimes called text.

comma separated values

A file format (.csv) used to hold tabular data, e.g. from a spreadsheet or database table. It stores it as a text-based file using commas (or semi-colons in some locations) to separate the data items.

AutoSum

A function within Microsoft Excel that adds together the contents of a number of cells.

AVERAGE

A function within Microsoft Excel that calculates the mean (average) of a list of numbers.

automatic teller machine

A machine where customers can access their bank accounts using a card and PIN; usually used to withdraw cash from their account.

animation

A rapidly changing set of images (either in 2D or 3D) which creates the illusion of actual movement.

control system

A set of devices which manage, command or regulate the behaviour of other devices or systems.

algorithm

A set of rules which shows how to solve a problem.

break

A split between two pages, sections or columns, or inserted to force text wrapping at the end of a line of text.

changeover

A stage in systems analysis where the new system is introduced by one of four methods: direct, parallel, pilot or phased changeover.

cascading stylesheet

A stylesheet saved in CSS format with a .css file extension. This allows the stylesheet to be attached to each webpage to define how to display the content layer of a webpage, without the page needing to contain the style tags. If a number of cascading stylesheets are used, the multiple style definitions will cascade into one.

chip and PIN

A technology that is used in debit and credit cards for payment in stores or use with ATMS. The chip is read by a card reader machine and compares it with the number typed in by the customer. It helps to ensures security of transactions.

chip and PIN readers

A technology that is used with credit/debit/loyalty cards which contain a chip as well as a magnetic stripe. These are used at EFTPOS terminals, where the customer enters their PIN using a keypad and this is compared with the number stored on the chip.

broadband

A telecommunications method in which a wide band of frequencies is available to transmit data. It allows internet traffic and normal telephone traffic to share the same communication lines.

clipboard

A temporary storage area used by the operating system to hold information that you cut or copy it, ready to be pasted at a later time.

actuator

A transducer which takes signals from a computer and converts them into some form of motion (e.g. motors, pumps, valves etc.).

concept keyboard

A type of keyboard where icons or phrases replace letters and numbers.

byte

A unit of memory (usually equal to eight binary bits); more commonly shown as Kbyte (just over one thousand bytes), Mbyte (one million bytes), Gbyte (1000MB) or Terrabyte (1000GB).

command line interface

A user interface that requires a user to type in instructions, choose options from a menu, open software, etc.

cell padding

An HTML attribute used with the table tag to specify the space between the cell wall and the cell content.

cell spacing

An HTML attribute used with the table tag to specify the space between the cells.

ascii

An abbreviation for American Standard Code for Information Interchange. This is the standard set of codes (numbers) used by the computer to identify each letter and symbol of the character set (on the keyboard).

check digit

An extra digit added to a number (often at the end) which is used to check for errors during transmission/reading of the number, e.g. in barcodes.

barcode reader

An input device that can read/scan barcodes using laser light.

blu-ray disk

An optical disk with very large capacity (currently the largest of all the optical media) using laser light close to the blue/violet spectra, which permits much larger storage capacity.

3D inkjet printer

An output device that produces solid 3D models using a modified inkjet printer and resins to replace inks.

blogger

Someone who maintains a blog.

bookmark

The address (URL) of a webpage saved by a user so that it can be revisited at some later date.

boot file

Code used to tell computer what to do when it first starts up (sometimes referred to as the BIOS).

basic input/output system (BIOS)

Code used to tell computer what to do when it first starts up (sometimes referred to as the boot).

Boolean data

Data that can have only two possible answers: true (1) or false (0).

abnormal data

Data that is of the wrong type (e.g. text in a numeric field) or is outside the accepted range (e.g. an exam mark percentage of 110).

contiguous data

Data that is placed together and can be selected in a single range.

analogue data

Data which represents physical constantly varying quantities such as time, temperature, etc.

absolute referencing

Fixes a cell reference within a spreadsheet so that when the formula is copied this cell reference never changes.

absolute value

Fixes a value so that it cannot change, for example in a webpage a table width can be set to 300 points. This table will always remain 300 points wide and will not change if the size of the browser window is changed.

asymmetric digital subscriber line

High-speed internet access service that uses existing telephone networks to send/receive data at much faster speeds than a dial-up modem.

back-end database

Is a database that is accessed through an application program rather than the database software. It does not store database elements like queries, forms or reports.

brightness

Is a measure of the intensity of light from a point on an image. It is a measure of the amount of red, green and blue light reflected from, or transmitted through any given point on an image. It is sometimes called luminous brightness.

closed question

Is a question which has only specified answers like "yes" or "no", or a multiple choice question. Users are always restricted to the answers that they can give in a closed question. For example: "Do you like school? Answer Y or N". A similar open question is "How do you feel about school?"

contrast

Is the difference between the amount of colour (or greyscale) between two different features within an image.

colour depth

Is the number of bits used to store the colours in each pixel. It is sometimes called bit depth or bits per pixel (bpp). For example: If an image has 24bit colour depth tis would be displayed as 224 colours (about 16.7 million), which would only be visible on a computer with a 24 bit graphics card (video adapter) and suitable monitor. A 24 bit colour depth has 8 bits per channel (red, green, blue).

body text

The basic style of text within a document, commonly used for all of the paragraphs.

content layer

One of the 3 layers in web page development. The content layer is used to define the structure of the webpage, often using tables or frames and the content of the pages including text or images and hyperlinks to other pages. The content layer is often written in html or xhtml.

behaviour layer

One of the 3 layers in webpage development. The behaviour layer is used to do 'an action' (rather than just display or link to other pages) and often uses script languages embedded into the HTML. There are many different script languages but the most common for web development are Javascript, PHP, Perl and CGI.

Bluetooth

Open wireless protocol over a short distance that allows devices to communicate using radio waves instead of wires.

barcode

Optical machine-readable representation of data that uses thick and thin lines to represent numbers.

CD-RW

Optical storage device that can be recorded on more than once, i.e. can be rewritten.

CD-R

Optical storage device that can be recorded on only once.

audience notes

Printed copies of the slides from a presentation, which are given to the audience so that they can take them away and refer to them after the presentation.

attribute

Provide additional information about HTML elements. Attributes follow the start tag and come in name/value pairs. E.g. <table border="1"> where the table tag has an attribute called border which has a value set to 1.

bit map

Representation, consisting of rows and columns of dots, of a graphical image in a computer. The density of the dots is called the resolution. In computer screens/monitors the dots are referred to as a pixels.

backing storage

Secondary storage device that allows a user to back up data from a computer system (e.g. CD, DVD, floppy disk, memory stick).

.gif

See GIF

.htm

See HTML

.jpg

See JPEG

.mp3

See MPEG-3

.mp4

See MPEG-4

.pdf

See PDF

.png

See PNG

.rar

See RAR

AP

See access point

analogue sensor

See analogue device

ADSL

See asymmetric digital subscriber

ATM

See automatic teller machine

BIOS

See basic input/output system

.css

See cascading stylesheet

.csv

See comma separated values

CLI

See command line interface

CMOS

See complementary metal oxide semiconductor

browse

To read and navigate through a series of webpages received from the internet.

bus network

Type of network where all the stations are connected to a central cable.

complementary metal oxide semiconductor

Type of semi-conductor chip that holds data (usually the BIOS) without the need for an external power source.

access point

Used in wireless networks to allow access to the network at various points using wireless technology (e.g. an airport will have several APs allowing 100 per cent coverage for users).