Glossary

Here is a list of common terms to do with the Internet and PCs in general. Hopefully it should help cut down on the jargon used within this site and hopefully make computers and the Internet a little less daunting.

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

Address
An address is a unique identifier assigned to a web page. The address is more commonly referred to as the URL (Uniformed Resource Locator).

ADN
(Advanced Digital Network) Often refers to 56kbps leased line

ADSL
(Asymmetric digital subscriber line) ADSL is the most widely deployed form of DSL technology. Most homes and small businesses currently using DSL technology use ADSL.

Applet
A multimedia application written or embedded in the Java language such as animation or sound, viewable only in a Java-enabled browser such as Netscape 2.0 or HotJava.

Anonymous FTP
Users may gain access to a remote server using FTP without actually having an account on that server. The user's E-mail address is usually given as a password and the user name 'anonymous' is assigned to the user by systems supporting this service.

Archie
A database of anonymous ftp sites and their contents, "Archie" keeps track of the entire contents of these sites, and allows users to search for files on those sites using various different kinds of filename searches.

Archive
Often compressed, archives are usually large files containing several smaller files. Commonly used archive file formats are ZIP, TAR, ARJ, LZH, UC2.

Archive site
Contains archived files of many kinds, available for users to download either by FTP or E-mail.

ARJ
Allows the user to store one or more files in a compressed format in an archive file. This saves space both in the compression and in the saving of disk sector clusters. Particularly strong compressing databases, uncompressed graphics files, and large documents. Named after the creator, American programmer Robert Jung.

ASCII
(American Standard Code for Information Interchange) a file containing only text characters: numbers, letters, and standard punctuation.

ATM
(Asynchronous Transfer Mode) a new communications standard that is currently in the later stages of development. ATM is designed to transfer voice, video, and other multimedia data that requires short bursts of large quantities of data that can survive small losses but must be broadcast in real time.

Attachments
Multimedia files that are 'attached' to an E-mail; can be text, graphics, sound, video, spreadsheet, database, or even an entire application.

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Backbone
A central high-speed network established by a company or organisation for connecting independent sub-networks.

Bandwidth
In simplistic terms, bandwidth is the amount of information travelling through a single channel at any one moment in time.

Baud Rate
Speed at which data travels through a modem, measured in bps (bits per second). Most modems today range from 2400 to over 50,000 bps.

BBS
(Bulletin Board System) a computer system usually run by local users making files available for downloading and setting up electronic discussion forums.

Binary
Binary data is a direct representation of the bits stored in RAM on a computer. Much more compact and accurate than ASCII.

Bit
(Binary DigIT) the smallest unit of computerized data, comprising of either a 1 or 0. A combination of bits can indicate an alphabetic character, a numeric digit, or perform a signaling, switching or other function. Bandwidth is usally measured in bits-per-second.

Body
In E-mail terms, the part of the message containing the most textual content, sandwiched between the Header and the Signature.

Bookmark
Virtual bookmarks work pretty much the same as the real ones. They record a URL or web page to enable you to refer back to at a later date.

bps
(Bits Per Second) speed at which data transfer is measured.

Browser
(Often called a 'Web Browser') allows the user to search the World Wide Web and other Internet facilities using a Graphical User Interface. Examples are Mosaic and Netscape.

Byte
A unit of data, generally formed from 8 bits. Example: 01101010

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CGI
(Common Gateway Interface) an interface-creation scripting program that allows you to make WWW pages on the fly based on information from fill-in forms, checkboxes, text input etc.

Client
In a Client-Server relationship, the client is a computer running programs or applications from the server, or accessing files from it.

Compress
The act of discarding redundant or semi-redundant information from a file, thereby making it smaller.

Cookie
A Cookie is a piece of software which records information about you. It holds this information until such time that the server requests it. For example, if you are browsing around a virtual shop, each time you place an item in your basket the information is stored by the cookie until you decide to buy and the server requests the purchase information.

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Daemon
A program that runs in the background whenever needed, carrying out tasks for the user. They 'sleep' until something comes along which needs their help; most commonly found on Unix systems.

Dialup
'Dialup Access' or a 'Dialup Account' is when a modem is used to gain access to the Internet via a network.

Domain Name
Unique address identifying each site on the Internet, usually of two or more segments separated by full stops.

Domain Name Server
Computers connected to the Internet whose job it is to keep track of the IP Addresses and Domain Names of other machines. When called upon, they take the ASCII Domain Name and convert it to the relevant numeric IP Address.

Domain Name System
Allows users to relate to computers on the Internet by using textual addresses (eg. www.icuknet.co.uk) for ease of use, rather than the IP Address system.

DOS
(Disk Operating System) simple operating system developed by Microsoft, allows extensions by other programs.

Download
When you transfer information off a remote machine connected to the Internet onto your local machine, you are downloading data.

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E-mail
Method of communication whereby an electronic message is sent to a remote location and received by another user at a specific E-mail Address.

Emoticons
These are the sideways smiles and frowns used in email to indicate emotions. E.g. :-) would indicate a smile and :-( would indicate a frown!

Ethernet
A type of network cabling allowing theoretical data transfers of up to 100Mb per second.

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FAQ
(Frequently Asked Question) Lists of Frequently Asked Questions (and their answers) covering all manner of topics can be found across the World Wide Web, allowing the user to search for a query that somebody has already found the answer to.

FDDI
(Fibre Distributed Data Interface) is a standard for transmitting data through optical fibre cables at a rate of around 100 million bps.

Filename extension
Commonly a three or four-letter extension on the end of a file name designating the file type. There are hundreds in existence, and new ones frequently being invented. Examples are: .txt (text file), .gif (Graphics Interchange Format).

Finger
A Unix program which displays information about a particular user or all users logged on the system, or a remote system.

Firewall
Secures a company or organisation's internal network from unauthorised external access (most commonly in the form of Internet hackers).

Flame
An insulting or derogatory message usually sent via E-mail as punishment for breach of netiquette. There have been instances of 'Flame Wars', when other people join in the heated exchanges. In either case, not recommended.

Forms
Certain Browsers support electronic fill-in forms. A form on a Web Page can be filled in by users all over the world, and the information sent electronically to the relevant domain site.

Freeware
Software allowed to be distributed free by the author, but often with certain conditions applying (ie. the software cannot be modified etc).

FTP
(File Transfer Protocol) one of the main ways files are transferred across the Internet. An FTP Site is that which is provided by a company or organisation as a depository for all kinds of files which users may download.

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Gateway
The interface between two opposing protocols. By means of software and hardware a gateway allows connection between otherwise incompatible networks.

GIF
(Graphics Interchange Format) developed by Compuserve, GIF is a platform-independent file format, used extensively throughout the Internet for graphics files. Compresses files using a 'lossless' method which ensures picture quality is not diminished.

Gigabyte (GB)
A thousand Megabytes.

Gopher
Internet Gopher is a distributed document search and retrieval system. It takes a request for information and then scans the Internet for it. The protocol and software follows a client-server model, and permits users on a heterogeneous mix of desktop systems to browse, search, and retrieve documents residing on multiple distributed server machines.

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Header
In E-mail terms, this is the part of the message indicating who the sender is and some other brief details, such as the subject of the message.

hit
As used in reference to the World Wide Web, “hit” means a single request from a web browser for a single item from a web server; thus in order for a web browser to display a page that contains 3 graphics, 4 “hits” would occur at the server: 1 for the HTML page, and one for each of the 3 graphics.

Home Page
On the World Wide Web, this is the main navigation page owned by a company, organisation, University, individual, etc, from which hyperlinks are made to other pages on the site (or other sites).

Host
You usually connect to a host computer whenever you use the Internet such as our ICUK servers.

HotJava
A Web browser developed by Sun Microsystems expanding traditional browser capabilities by allowing dynamic functions instead of just static text and images.

HTML
(HyperText Markup Language) the tagging language used to format Web pages. Allows pictures and text to be combined to create Web documents, and the most important feature - hypertext - making it possible for links to be made between different documents.

HTTP
(HyperText Transport Protocol) used on the World Wide Web since 1990, this application-level protocol is essential for the distribution of information throughout the Web.

Hyperlink
In World Wide Web pages, hyperlinks are highlighted text or images which, when selected (usually by clicking the mouse button), follow a link to another page. Hyperlinks can also be used to automatically download other files as well as sounds and video clips.

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Image Map
An image with clickable 'hot spots', allowing several hyperlinks from a single image file. For example, the image could be of a country, split into different areas, each of which could be clickable and hyperlink to a larger view of that specific area.

internet
When spelt with a lower case i, it is a group of two or more networks connected together.

Internet
With a capital I, it is the collection of all the interconnected networks in the world, and is often simply referred to as the 'net'.

IP
(Internet Protocol) the main protocol used on the Internet.

IP Address
Unique 4-number code designated to every Domain on the Internet. Each Domain also has a Domain Name as well as an IP address to make site addresses easier to remember.

IRC
(Internet Relay Chat) real-time world-wide electronic chat program allowing the user to communicate with other people across the globe.

ISDN
(Integrated Services Digital Network) Digital telephone line allowing faster data transfer rates than existing analog lines. Allows simultaneous transfer of voice, data and video information.

ISP
(Internet Service Provider) A Company or Organisation, such as Legend Internet, dedicated to providing businesses or home users access to the Internet, usually for a fee.

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Java
Developed by Sun Microsystems, Java is a Web programming language supporting online multimedia effects, such as simple cartoon-like animation, background music and continuously updated information in Web pages.

JPEG
(Joint Photographic Experts Group) a standard of image compression developed especially for use on the Internet. Most photographic images can be highly compressed using this method, without greatly diminishing image quality.

.jpg or .jpeg
Filename extensions given to JPEG graphics files.

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Kilobyte
1024 bytes, usually rounded down to a thousand bytes for simplicity.

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LAN
(Local Area Network) see below.

Leased Line
A rented, high-speed phone link for private use, available 24 hours a day.

Link
Link puts the hyper in hyperlink. Links are the connections between hypertext pages. Every time you click on highlighted text to go to another page you're following a link.

Local Area Network
Usually referred to as a LAN, this describes a group of computers commonly in the same building, connected by network cables.

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Mailserver
The computer (and software running on it) that allows sorting and retrieval of E-mail messages.

Megabyte (MB)
The unit of measurement for a thousand Kilobytes; a million bytes.

MIME
(Multipurpose Internet Mail Extensions) a format designed originally to include images, sounds, animations and other types of documents within Internet mail messages.

Mirror site
An FTP site containing exactly the same files as the site it is mirroring. Sites may be mirrored several times, often in different countries around the world. They relieve the load that can be placed on a very popular FTP site, making it easier for users to gain access and download files faster.

Modem
(MODulator-DEModulator) allows the transmission of digital information over an analog phone line.

Mosaic
Web browser written by a group of people at NCSA. Provides a Graphical User Interface for accessing data on the World Wide Web.

MPEG
(Motion Picture Experts Group) video compression format used for movie or animation clips on the World Wide Web.

.mpg or .mpeg
Filename extension for MPEG movies.

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NCSA
(National Center for Supercomputing Applications) powerful organisation that launched the Mosaic Web Browser in 1993 for Windows, x-Windows and Macintosh platforms.

Netiquette
Informal, largely undocumented set of rules designed to make the Web a polite and civilised 'society'.

Netscape Communications
Creators of Netscape Navigator, one of the most popular Web browsers. Became notorious after introducing several HTML 'extensions' that were unsupported by other browsers.

Network
Two or more computers linked together and able to share resources constitutes a network.

Network Time Protocol
Internet protocol ensuring that the correct time is transmitted.

Network time server
Using Network Time Protocol, you access this machine to get the right time.

Newsgroup
Thousands of Newsgroups exist, distributing information on different subjects using Usenet.

Newsreader
Program that allows the user to read Newsgroup messages via Usenet.

NIC
(Network Information Center) the location where all the data is organised for a certain network.

NNTP
(Net News Transport Protocol) Usenet news uses this transfer protocol for shifting files around the network.

Node
Any single computer connected to a network.

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Offline
When your computer performs an operation when it is not connected to any other computers, it is working offline.

Online
Your computer is working online when it performs an operation and is connected to other computers.

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Packet
Information moves around the Internet in 'packets'; chunks of data each with their own destination address. Think of packets as sealed envelopes containing data, with addresses written on them. They all go through the system, and usually end up at the correct destination. The more envelopes the system must handle, the slower the process becomes.

Page
A World Wide Web 'page' is the name given to a basic Web document, such as the one you are viewing at the moment.

Plug-In
There are many things that your browser can do such as displaying images and web pages. Other things are beyond its capabilities and that's where the plug-ins are introduced. Shockwave and RealAudio are examples of plug-ins required for audio and video.

POP
(Post Office Protocol) provides a store-and-forward service, intended to move E-mail on demand from an intermediate server to a single destination machine, usually a PC or Macintosh.

PPP
(Point to Point Protocol) PPP is a kind of Internet connection that allows a computer to use Internet protocols to become a part of the Internet. Requires a modem, a standard telephone line and an account from a service provider.

Protocol
Method by which computers communicate to each other over the Internet in order to provide a service.

Public access provider
An organization that provides Internet access for individuals or other organizations, often for a fee.

Public domain
Refers to software that anybody can use or modify without authorisation.

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Router
A special-purpose computer (or software package) that handles the connection between 2 or more networks. Routers concentrate on looking at the destination addresses of the packets passing through them and deciding which route to send them on.

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Scripting language
Series of programmed commands that designate how one computer communicates with another computer.

Server
Within a network, a server makes files available to client programs located on other computers when requested.

Service Provider
The role of a Service Provider is to provide subscribers a gateway to the Internet.

Shareware
Software distributed freely, but with certain conditions applying to it. Either the software is released on a trial basis only, and must be registered after a certain period of time, or in other cases no support can be offered with the software without registering it. In some cases direct payment to the author is required.

Signature
The automatic addition of a few lines at the foot of an E-mail. These usually consist of the sender's E-mail address, full name and other details.

SLIP
(Serial Line Internet Protocol) like PPP, lets you use a modem and phone lines to connect to the Internet without connecting to a host computer.

Smileys
Characters often used in News messages, E-mails and on Web Pages to offer some degree of character or emotion. Example :-)

SMTP
(Simple Mail Transport Protocol) often referred to as sendmail, is designed to allow the delivery of mail messages to Internet users.

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Tag
In HTML terms, a 'tag' is used for marking-up text in various ways so that it is formatted in a Web document. They are sometimes called 'Markup Tags'.

T-1
Network link used on the Internet allowing speeds of up to 1.54 megabits/second.

T-3
Higher speed (45 megabits/second) Network link used on the Internet.

TCP
(Transmission Control Protocol) works in conjunction with IP to ensure that packets reach their intended destinations.

TCP/IP
(Transmission Control Protocol / Internet Protocol) the two fundamental protocols which form the basis of the Internet.

Telnet
Terminal emulation program allowing an authorised user to access another computer on the Internet and use that computer as if it were local (when in reality it could be several thousand miles away).

Terabyte
1000 gigabytes

Terminal
Piece of hardware that allows commands to be sent to a computer, usually by means of a keyboard and display unit.

Terminal emulator
Allows a PC to emulate several terminal types.

Thread
In a Usenet group, this is a list of messages loosely relating to one another (using the same 'thread').

Timeout
The facility whereby after a certain period of inactivity the connection is dropped.

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Unix
An Operating System typically written in C, and designed for multi-user environments. It has TCP/IP built in, and is therefore one of the most popular operating systems for servers on the Internet.

Upload
Transfer of files off a local computer up to a specified remote computer (as opposed to download where files are pulled off a remote machine).

URL
(Uniform Resource Locator) resource addressing scheme of the World Wide Web. Assists in locating and identification of multimedia resources or multiple copies of resources.

Usenet
Specialised network linking thousands of newsgroups covering every subject under the sun.

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Veronica
(Very Easy Rodent Oriented Net-wide Index to Computerised Archives) A resource-discovery system providing access to information resources held on most ( 99% + ) of the world's gopher servers. In addition to native gopher data, veronica includes references to many resources provided by other types of information servers, such as WWW servers, usenet archives, and telnet-accessible information services.

Virus
A virus is virtual evil. It can hide anywhere where a computer stores information. They have the ability to transfer from computer to computer with the use of the Internet and various other networks. A virus can do a number of things to a recipient such as reformatting hard drives (destroying data).

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WAIS
(Wide Area Information Servers) an architecture for a distributed information retrieval system. WAIS is based on the client-server model of computation, and allows users of computers to share information using a common computer-to-computer protocol.

Wide Area Network (WAN)
Group of computers located geographically apart, usually belonging to a single company or organisation, connected together using dedicated lines or by satellite to simulate a local network.

WinSock
(WINdows SOCKets) Windows utility program allowing users connected by SLIP, PPP or other direct connection to communicate with other computers on the Internet by TCP/IP.

World Wide Web ('WWW' or 'Web')
Specialised Internet Service allowing users to connect to remote sites, with information presented as text with hypertext links. These links can be used to refer to almost all other resources on the Internet. Graphics can be embedded into Web pages, but can only be viewed using a graphical Web browser. Other applications supported are sound files and movie files.

Worm
A search utility on the World Wide Web that locates resources following user-determined guidelines.

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XMODEM
A popular but slow file transfer protocol.

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YMODEM
Another file transfer protocol, slightly faster than XMODEM.

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.ZIP
Files that have been compressed using the PKZIP program have this filename extension. They can be decompressed using the PKUNZIP utility.

ZMODEM
The fastest and most popular file transfer protocol, due to its efficiency and crash recovery properties.