Internet Glossary

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Access provider See ISP.

Address book List of names and mail addresses of all registered net-work users. The Address book is used by the post office to verify that messages are correctly addressed and to deliver them to the correct recipient. The full list of all available users is called the global address book.

Alias simple name for a user or group of users, interpreted by e-mail software. Using an alias means you don't have to remember com-plicated mail addresses.

Attachment File linked to an e-mail message and sent at the same time.

Authoring Creating a WWW page using HTML codes to format images and text.

Backbone A very fast communications link that connects major ISPs together across the world. Large companies may also have a high-speed backbone linking many network servers together.

Bit A basic storage unit used in computers; a bit can only be one of two values '1' or'0'.Data is stored in a computer as a combination of bits (eight together are referred to as a byte).

Body Main part of an electronic mail message, as opposed to header and attachment.

bps Bits (binary digits) per second - the measure of data communi-cations speed. It's commonly confused with, but not the same thing as, baud, which refers to the number of transitions made per second and which equals bps only at low speeds such as 300 bps.

Bridge An interconnection device that can connect LANs at the data link level, so allowing similar LANs using different transmission methods, for example Ethernet or Token Ring to talk. Bridges are able to read and filter the data packets and frames employed by the protocol and use the addresses to decide whether or not to pass a packet.

Browser Software program used to navigate through WWW pages stored on the Internet.

Byte Basic unit for storing data in a computer; a byte is made up of eight separate bits and can store numbers between 0 and 1024.To put it in a more understandable way, a byte is normally used to store a character or digit.

CCITT Comit Consultatif Internationale de Telegraphie et Telephonie: the United Nations group responsible for setting inter-national telecommunications standards. Its recommendations for standard phone lines always start with the letter V (see below).

CGI Common gateway interface: a standard that defines how a WWW page can call special scripts on the Internet server to carry out functions that enhance a web page; see also Pen.

Client Network workstation that communicates with a server; an e-mail letterbox.

Client server A computing system consisting of networked 'clients' which request information and a central 'server' which stores data and manages shared information and resources. Client-server soft-ware, or architectures, are trying to reduce the amount of data traffic flowing over the wires between clients and server. It does this by processing data at the server as well as simply retrieving it. For example, a client PC with a simple front-end application asks the server to find all contacts in South London. The server trawls through the database and only returns the correct matches. The alternative is for the client to request the entire database to be sent which it then searches. The difference is subtle, but is the new design on which server-based SQL databases and similar work. The result is that the network is not stressed so heavily. The only caveat is that the server does more by having to run an application in par-allel with the NOS.

Dial up A connection that uses a standard telephone line or ISDN link to connect your computer to an ISP

Distributed processing A technique to enable processors or computers to share tasks amongst themselves most effectively Each processor completes allocated subtasks independently and the results are then recombined.

Domain name The unique name that identifies the location of an Internet server or computer on the Internet. For example, '' identifies the server provided by Microsoft.

Domain name server (DNS) A computer that stores the names and addresses of every other computer on the Internet. This is used to lookup the correct destination address when you try and access a WWW page or send an electronic mail message. The DNS actually converts the name into a complex and unique pattern of numbers called the IP address.

Duplexing A technique to increase the fault tolerance of networks. In a duplexed disk system, there are two identical controllers and disk drives. Data is written to both via a separate controller. If one goes wrong the second device is switched in under software control with no effect to the user This is a more fault tolerant system than disk mirroring.

E-mail Electronic mail: the biggest use of the Internet is to send electronic mail. You can send messages to any other user on the Internet if you know their address.

FAQ Frequently asked question.

Finger A software program that will go off and retrieve information about a user based on their electronic mail address.

Folder 'Container' for mail messages in a user's mail front-end -rather like a directory under DOS.

FTP File transfer protocol: system used to transfer files between computers linked to the Internet.

Gateway High-level interconnection device which passes packets of data from one type of networking system, computer or application to another by convening the protocols and format of the packets used.

Gateway (e-mail) Interface between different e-mail systems; gate-ways convert protocols to connect dissimilar networks.

GIF The most common graphics format used to store images dis-played on the Internet.

Gopher An (older) menu-based system that lets you navigate the Internet; has now been mostly replaced by the www

Hayes AT The de facto standard command set for controlling a modem from a communications program. Even more so than a printer that doesn't work with Epson or Hewlett-Packard software drivers, a modem that doesn't follow one of Hayes' command sets is a software-incompatible oddball.

Header Part of a message that contains the recipient's address, sender's name and any delivery options.

Home page The opening page of a Web site (normally stored in a file called 'index.html').

HTML Hypertext markup language: standard set of codes that describe formatting functions for Web pages including which text is bold, italic, different sizes and how they link to other Web pages.

HTTP Hypertext transfer protocol: the language used by a browser to ask an Internet server for information about a Web page.

Hypertext A way of linking one word or image to another page; when the user selects the word or image, he jumps directly to the new page. This is the basis of navigating around the www - if you click on an underlined word in a Web page, it will link you to another section of the page or to another page.

Internet Millions of computers linked together to form a global network allowing users to transfer information between any two computers connected to the Internet. No one person or company controls the Internet.

Intranet Private network of computers within a computer that pro-vide similar functions to the Internet - such as electronic mail, newsgroups and the WWW - but do not have the associated secu-rity risks of linking the company to a public network.

IP A unique number that defines a computer that is connected to the Internet. Each time you connect to the Internet you use an IP number that identifies you.

ISDN System that allows digital signals to be transmitted over a spe-cial telephone line using a special modem (called an ISDN adapter). ISDN transmits data at 64Kbps - much faster than a nor-mal modem - and makes a call and connects very quickly

ISP Internet Service Provider: a company that provides one of the permanent links that make up the Internet and sells connections to private users and companies to allow them to access the Internet. If you want to access the Internet you will (in most cases) have to have an account with an ISP The ISP normally has very fast fixed links to other ISPs on the Internet and provides telephone access numbers for users to dial in with a modem or ISDN adapter

JPEG File format used to store graphic images (although GIFs are more usual).

Kbps Kilo bits per second: a measure of the amount of data that a device can transfer each second. A fast modem can transfer 28.8Kbps whereas an ISDN adapter can transfer 64Kbps.

LAN Local Area Network: a group of workstations PCs or Macs) that are physically and electronically linked using cabling. Network software allows each workstation to share files and resources, such as a printer. You can connect your office LAN to the Internet either by adding a gateway to your electronic mail software or by con-necting the LAN to an ISP with an ISDN or leased line.

Leased line A permanent communications link between two sites; companies that want to set up their own Internet server in-house would normally choose a leased line between their offices and the ISP. Two ISPs could use a fast leased line to connect to each other to transfer data.

Mail-enabled application A normal application from which it is possible to send mail without specifically calling up your e-mail package. Lotus is mail-enabling new releases of its Windows pack-ages to automatically call up cc:Mail; WinMail supplies macros to mail-enable standard applications.

Mail server A computer that stores incoming mail and sends it to the correct user, and stores outgoing mail and transfers it to the correct destination server on the Internet.

MIME Multipurpose Internet multimedia extensions: a way of send-ing normal document or data files using electronic mail software. MIME allows a user to send files over the Internet to another user without having to carry out any other actions. Before MIME was developed, you would have to first encode the file and then send it as a ten mail message.

Mirroring A means of improving fault tolerance in a network. In a mirrored disk system, two separate hard disks are connected to the same controller The same data is duplicated on the two drives by one controller. This offers a cheaper, but less secure, fault tolerance than disk duplexing.

MNP A set of error control standards developed by Microcom Inc. and adopted into the CCITT v42 standard. MNP allows a modem or communications program to detect transmission errors and request a resend.

Modem A device that lets your computer send and receive infor-mation over a normal telephone line. To connect to the Internet you need a modem that will connect to the ISP with which you have an account. A modem works by converting data into sounds that can then be transmitted over the telephone.

Name server A computer that provides a Domain name service. See DNS.

Naming services An imp ortant development within the last couple of years, spurred on by the importance of WAN s. It simply dictates that within a network, each node has a unique address and name of any server or computer can reach and communicate with any other

NetBIOS Network Basic Input/Output System: a low-level software interface that lets applications talk to network hardware. If a net-work is NetBIOS-compatible, it will respond in the same way to the set of NetBIOS commands, accessed from DOS by the Int 5Ch interrupt. NetBIOS used to be the de facto standard, thanks to a lack of international standards, but its limitations and age now make it near-redundant.

Netscape Navigator One of the most popular WWW browsers (to download a free trial version, look at '').

Newsgroup One area within what's often called Usenet - a news-group lets anyone discuss a particular topic. There are over 15,000 different newsgroups that cover just about every subject available. Newsgroups are one of the most active parts of the Internet: you can read messages from other users, comment on them or submit your own message.

Packet The basic unit of data sent over the network during inter-communication. A packet includes the address of the sending and receiving stations, error control information and check proce-dures, and, finally, the information itself

PoP Point of presence: a telephone number that links to a modem at an ISP Normally the ISP will have hundreds of modems linked to local telephone numbers (PoPs) around the country.

POP 3 System used to transfer electronic mail messages between a user's computer and a server (at an ISP).

Post office Central store for the messages for users on a local area network; the post office will also ensure that messages are deliv-ered locally and might have a gateway to route any mail to other post offices or mail systems.

Protocol Rules covering format and timing of messages on a net-work.

Receive log Tracks total mail received at that point, whether on a mail server or a client.

Remote client User accessing mail without being connected to the mail server's local network. The user can be elsewhere in a WAN, or accessing the mail system via a modem link.

Router A device that lets you connect your office network server or in-house Internet server to the Internet via a leased line. You do not need a router for an ISDN or modem connection.

Rules Method of testing incoming messages for certain conditions (such as the name of the sender or the contents) and acting upon them. For example, a rule could define that any mall from user 'boss' should be moved to the urgent folder

Shared folder Mail folder accessible to more than one user, func-tioning as a bulletin board.

SMTP Simple Mail Transfer Protocol: system that allows servers to exchange electronic mail messages in transit from the sender to the recipient.

SSL Secure sockets layer: method of securing a Web site by scrambling the information between the user and server - essential for secure payments and ordering.

TCP/IP Transmission Control Protocol I Internet Protocol: a set of communications protocols developed by the US Department of Defence (DOD), originally for use in military applications. TCP/IP bundles and unbundles sent and received data into packets, man-ages packet transmission and checks for errors across networks. Originally found binding Unix networks together; its flexibility and portability are making it a de facto standard for any LAN and WAN.

Telnet System that lets you connect to any computer on the Internet (that allows Telnet) and type in commands as if you were sitting in front of the computer In practice, Telnet is normally used when you are setting up your Web site to create directories, set up security and move files

UART Universal Asynchronous Receiver/Transmitter: the circuit that converts between the parallel data used by PCs and the serial data used by modems. Serial ports have a UART while internal modems supply their own. For high DTE rates on systems with a heavy pro-cessing load (typically those that use Windows), a 16550A UART provides better more reliable performance.

URL Uniform resource locator: the full address that defines where a Web page is stored on a server connected to the Internet.

Usenet The most popular collection of newsgroups.

UUencoding Method of converting documents and files to a pseudotext format that lets them be transmitted as an electronic mail message. This gets around the internetís inability to transfer mall messages other than text. This has now been largely replaced by MIME.

V.32 The CCITT modulation standard for dial-up modems that allows data-transmission rates as high as 9,600 bps.

V.32bis The CCITT standard for data transmission at 14,400 bps and several slower rates.

V.42 A CCITT standard for error control. It's based on a European error control standard called IAP M, which also can use MNP Classes 2-4.

V.42bis A CCITT standard for data compression, requiring V.42. Under ideal conditions, V42bis can provide up to fourfold com-pression.

WAN Wide area network: multiple small, linked local area networks or a network with multiple servers linked together using public telephone circuits, leased lines or high-speed bridges.

Web browser Software that lets you view Web pages stored on the Internet or on your computer

Web page Single file stored on a Web server that contains formatted text, graphics and hypertext links to other pages on the Internet. A Web page is created using HTML codes.

Web server Computer that stores the collection of Web pages that make up a Web site.

Web site Collection of Web pages from one person or company that link together with hypertext links to form a home that users can visit on the Internet.

Winsock Utility software that is required to control the modem when connecting to the Internet under MS-DOS or Windows 3. Windows 95 has its own version of this utility built in.

WWW World Wide Web: the collection of the millions of Web sites and Web pages that together form the Web of information that allows a user to see a graphical view of the Internet and the infor-mation it contains.