Computer Glossary

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INDEX

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 -

acronym
Words that are usually made up of the first letters of a phrase or saying, such as BFN, which is an acronym for Bye For Now.
ADO
ActiveX Data Object, a programming interface designed by Microsoft to access data in a database.
ADSL
Asymmetric Digital Subscriber Line - A variant of DSL with higher download speed than upload speed.
application
In Microsoft speak, an application is a program.
ASCII
American Standard Code for Information Interchange, a 7-bit character code in widespread use.
association table
See file association table.
attribute
See file attribute.
- B -

bandwidth
The capacity of a link between computers to transfer data, measured in bits per second (bps).
beta program
New software that has been tested by the writers, and is available for further testing by users. They may have bugs in them that should be reported to the author.
See also; shareware, freeware.
billion
One thousand million (10⁹).
BIOS
Every PC has a BIOS (pronounced bye-oss) chip, which means Basic Input Output System. It controls the basic features of a PC and tells the operating system things like time, date and the size of your hard disk.
bit
Abbreviation for binary digit, taking the values 0 and 1.
bug
1. A small insect or beetle.
2. An infectious disease or virus.
3. A covert listening device.
4. A mistake in the code of a software application that causes a problem to the user.
byte
A group of 8 bits capable of representing a character or a number from a set of 256.
- C -

cache
A RAM store for frequently used data or files. Data can be accessed from a cache faster than from its original source.
character
Any letter, numeral, punctuation or other symbol of a character set, coded as a number and stored in the computer, usually in one byte. Some characters are used for layout purposes, such as space, new line, tab, form feed, etc. See also ASCII.
client
A program that enables a computer to use the services provided by other computers.
CMOS
A type of memory, the contents of which are not lost when you switch off. Used to keep permanent (but changeable) data about the computer's configuration.
compact flash
Matchbook sized memory cards with no moving parts. These slot into various devices to store data.
cookie
Data item in your computer's memory placed there by some external Internet site containing information useful to that site, usually for commercial reasons. Another use of a cookie is to save personal data to avoid re-typing it when you re-visit a site.
CPU
Central Processing Unit, performing arithmetic and logical operations at high speed, controlled by a program.
compression
See data compression.
- D -

data
Numbers and symbols representing information.
data compression
A technique for removing the redundancy from data, thus compressing the data into a smaller storage area. See also zip.
database
A file of structured data. See also spreadsheet.
defragment
(defrag) To reorganise the data stored on a hard disk so that it can be accessed as quickly as possible by a PC. A fragmented disk can affect system performance.
DHCP
Dynamic Host Configuration Protocol. A protocol that allows a computer to be connected to a network and to automatically obtain various parameters that it requires to operate network services.
directory
Also called "folder". Used to describe a section of disk storage that can hold files and other sub-directories. See tree
domain
Part of the name for an internet computer that specifies its location and whether it is in a commercial, educational or government organization.
DOS
Disk Operating System and command interpreter (COMMAND.COM) as used on the original IBM-PC.
download
Transfer of data to your own computer from a remote computer.
DSL
Digital Subscriber Line - Uses ordinary copper telephone line to transmit data at speeds up to 7Mb/s (7 megabits per second), although typical DSL connections yield between 256 kb/s and 768 kb/s (see also ADSL).
DVD-ROM drive
Digital Versatile Disc-Read Only Memory. These drives will play CD-ROMs and DVDs.
- E -

e-mail
Electronic mail; one of a wide rage of services provided by the Internet, enabling messages and multi-media data to be transmitted quickly between computers anywhere in the world.
encryption
Using a secret code so that people cannot read files without permission.
Ethernet
A specific method of enabling more than one computer to work as a network using cables.
extension
See file type.
- F -

FAT
File Allocation Table; a table used by operating systems (e.g. DOS) to keep track of storage location usage on disks.
file association table
A table of data held by Windows that associates file types with application programs. A double click on a file name will open the file using the associated program. Whilst a useful operational convenience, it nevertheless blurs the distinction between programs and data to a novice user.
file attribute
A set of status bits associated with each file to denote such things as read-only, archive, system, hidden, etc. This data is held in the directory entry, not the file itself.
file type
Also called file extension; the set of (usually) three characters that follow the last dot in the file name. Used in Windows to help locate a suitable application program that can open the file (see file association table).
follow up
An article sent to a newsgroup commenting on a previously posted article.
FTP
File Transfer Protocol, a protocol for transferring files on the Internet.
freeware
Software that is completely free for anyone to copy into their computer and use. The author has donated it free of charge.
See also; shareware, beta program.
- G -

gateway
On the Internet, a gateway allows access to a higher level network of computers to overcome the limitation of the 32-bit (about 4,000,000,000) limit on internet addresses.
GIF
A graphics file format that uses data compression to reduce the file size.
GUI
(Graphical User Interface). A system that uses on-screen pictures which can be clicked on with a mouse to give computer instructions.
- H -

hacker
Someone who gains unauthorized access to a computer to look at, change or destroy data.
hexadecimal
Representation of numbers in base 16. The hexadecimal digits are 0 to 9 and A to F. See also octal.
HTML
HyperText Markup Language, the language used to form pages of data on web sites that can be interpreted by a web browser.
HTTP
Hyper Text Transfer Protocol, a protocol for accessing hyper text documents over the Internet.
hypertext
Text within a document containing links to other documents (or parts of the same document, as in this glossary).
- I -

information
Meaningful interpretation of data.
internet
Interconnection of computers world-wide providing information and communication services.
IP address
The unique number given to each computer on the net.
ISP
Internet Service Provider -- an organisation that provides access to the Internet to paying customers.
- J -

java
A language used to write programs which enables Web pages to include interesting features such as animations.
- K -

kilo-
Prefix to units to denote a multiple of 1000, but in computing, 1024. When abbreviated to the single letter, k, it is lower case; e.g. kHz = kilohertz.
- L -

launch
Microsoft speak for load and run a program.
link
1. A connection between two computers.
2. The highlighted text or pictures in a hypertext document.
- M -

MIME
Multipurpose Internet Mail Extensions. An internet standard, created to enable information other than plain text to be sent via electronic mail.
modem
(MOdulate / DEModulate). A device that allows computer data to be sent down an analogue telephone line.
- N -

network
A number of computers and other devices that are linked together so that they can share information and equipment.
newsgroup
An international discussion area on the Internet open to all on a vast array of subjects.
nibble
Half a byte. A group of 4 bits capable of representing a hexadecimal digit or a number from a set of 16.
- O -

octal
Representation of numbers in base 8 (i.e. in groups of three binary digits). See also hexadecimal.
ODBC
(pronounced as separate letters) is short for Open DataBase Connectivity, a standard database access method developed by Microsoft. The goal of ODBC is to make it possible to access any data from any application, regardless of which database management system (DBMS) is handling the data. ODBC manages this by inserting a middle layer, called a database driver, between an application and the DBMS. The purpose of this layer is to translate the application's data queries into commands that the DBMS understands. For this to work, both the application and the DBMS must be ODBC-compliant -- that is, the application must be capable of issuing ODBC commands and the DBMS must be capable of responding to them.
OEM
Original Equipment Manufacturer, a manufacturer who produces components for incorporating into complete systems. Often, OEM parts are similar to those sold retail but may be cheaper or sold with different software.
on-line service
A company that gives you access to its private network, containing various kinds of information, and usually gives you access to the Internet.
- P -

PC
Generally, Personal Computer; but often used to mean an IBM-Compatible personal computer.
PHP
A computer language used on the Internet to provide user interaction. The input data comes from the user and the results are returned to the user in the form of an HTML file.
ping
A short internet message that enquires if another internet computer is active. If it is, the other computer will send a reply message, often with some additional data. But some computers are configured not to reply.
pixel
Abbreviation for picture element.
plain text
Text without formatting other than spaces, newline, etc., using ASCII characters.
program
A set of computer instructions.
protocol
A set of rules that two computers agree to use when communicating with each other.
- Q -
- R -

RAM
Originally "Random Access Memory" but now means volatile memory (i.e. you lose what it contained when you switch off).
redundancy
Most computer data, for convenience of access, is not stored efficiently, i.e. it contains redundancy. See data compression.
registry
A large database used by Windows to keep track of various system settings, such as installed hardware and applications.
resolution (of a graphic image)
The number of pixels per inch (or per cm) that will be used for printing the image by default, thus determining the printed size. The displayed size depends on the screen resolution which is the number of pixels used in the width and height of the screen. A change of resolution will change the printed size but not the size as displayed on the screen.
ROM
Read Only Memory, the contents of which is not lost when the power is switched off (compare with "RAM" above).
router
A device that combines the traffic from a network of 2 or more computers, or lower level networks, and sends it towards the top level of the network. It also receives reply traffic in the opposite direction and sends (routes) it to the correct destination. See gateway.
- S -

shareware
Software that you can install on your computer, but there are conditions attached. Such conditions as: After an initial trial period you must pay for a registered version and support. Or the program may be a demo version, with limited features. You get a full featured version when you register.
See also; freeware, beta program.
spreadsheet
A flexible form of database in which arithmetic and logical operations can be performed on columns and rows, providing a versatile platform for data manipulation.
software
Programs that enable computers to carry out certain tasks.
- T -

thread
1. A sequence of articles sent to a newsgroup forming a discussion on a particular subject.
2. A sequence of program parts that a program can run through to perform some operation whilst multiprogramming with other programs using some of the same parts.
tree structure
A method of representing information in a structured hierarchical manner in the nature of a tree, starting at the root and working upwards to the leaves. In a computer, directories (also called folders) store files where a "file" may be another directory, and so on.
- U -

upload
Transfer of data from your computer to a remote computer.
URL
Uniform Resource Locator: the generalised form of web site address that provides a wide range of services over the Internet.
USB
Universal Serial Bus: a socket for connecting peripheral equipment that can be used without switching off the computer.
- V -

virus
A program specially designed to interfere with other programs and files.
- W -

World Wide Web
(Also known as WWW or the Web) Part of the internet made up of pages of information linked together by relevant hypertext links.
web browser
A program that interprets Internet web pages and displays their contents. Examples are Netscape and Microsoft's Internet Explorer.
- X -

xy recorder
A device that traces on a chart (a Cartesian xy-plane) the relation between two variables.
- Y -

Yahoo
One of the first WWW search directory services. Now has expanded services to include e-mail, chat, homepages and more.
- Z -

Zip
A file format. A .zip archive file contains many files and folders that are compressed and put into one file. The .zip file containing the collection of files can then be archived as a backup or distributed to others. To make use of the files in the .zip archive file, they first need to be unzipped.