What does it mean?
Please browse our glossary of commonly-used technology terms.

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Address, Email

A unique identifier of the form "username@domainname.com" specifying a virtual location to which email can be sent.

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Address, Internet

Also called IP address. The numerical sequence that serves as an identifier for an Internet server. An IP address appears as a series of four groups of numbers separated by dots. Every server has its own unique address.

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Anonymous FTP

A common way to make software available. Users are allowed to log in as 'guest' without a password and copy whatever has been made available.

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Backbone

High-speed networks that carry Internet traffic that carry Internet traffic around the world and meet at Network Access Points (NAPs). Internet Service Providers (ISPs) connect either directly to a backbone, or they connect to a larger ISP with a connection to a backbone.

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Bandwidth

A measure of data flow rate in digital networks typically in bits per second. The higher the bandwidth the larger the capacity to transmit data.

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BPS

Bits Per Second is the unit used for measuring line speed, the number of information units transmitted per second.

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Browser

A software component capable of rendering HTML pages and allowing for navigation of HTML links on the Internet (e.g. Internet Explorer, Mozilla Firefox, etc.)

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Byte

A component in the machine data hierarchy larger than a bit and usually smaller than a word; now nearly always eight bits and the smallest addressable unit of storage. A byte typically holds one character.

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Cache

A fast temporary storage where most recent or most frequent values are stored to avoid having to reload from a slower storage medium.

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Case-sensitive

Whether a text matching operation distinguishes uppercase (capital) letters from lowercase (is "case-sensitive") or not ("case-insensitive"). For example, a case-sensitive password will not recognize "Password" and "password" as the same, but a case-insensitive comparison would.

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Client

The role of a computer application or system that requests and/or consumes the services provided by another having the role of server. For example, a workstation requesting the contents of a file from a file server is a client of the file server.

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Cookie

A packet of information sent by a server to a World Wide Web browser and then returned by the browser each time it accesses that server, used to maintain state between otherwise stateless HTTP transactions, for example, to identify the user. Typically this is used to authenticate or identify a registered user of a website without requiring them to sign in again every time they access it. Other uses are, e.g. maintaining a "shopping basket" of goods you have selected to purchase during a session at a site, site personalization (presenting different pages to different users) or tracking which pages a user has visited on a site.

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Download

To transfer data from one computer to another. Downloading usually refers to transfer from a larger "host" system (especially a server or mainframe) to a smaller "client" system (such as a personal computer), and "upload" usually means from small to large.

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DSL

An abbreviation for Digital Subscriber Line. A family of digital telecommunications protocols designed to allow high-speed data communication over the existing copper telephone lines between end-users and telephone companies. The technology is geared to Internet access with its asymmetric versions (faster downstream than upstream) and short haul connections with symmetric versions (same rate coming and going).

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Email

Abbreviation for "Electronic Mail." Messages automatically passed from one computer user to another, often through computer networks and/or via modems over telephone lines (over the Internet). The message is composed by the sender using a special mail program. It is then passed to some kind of "Message Transfer Agent" (MTA) - a program which is responsible for either delivering the message locally or passing it to another MTA, often on another host. The message is eventually delivered to the recipient's mailbox - normally a file on his computer - from where he can read it using his own mail program.

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Encryption

Any procedure used to convert plaintext into ciphertext (encrypted message) in order to prevent any but the intended recipient from reading that data.

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Firewall

The software that monitors traffic in and out of a private network or a personal computer and allows or blocks such traffic depending on its perceived threat.

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FTP (File Transfer Protocol)

A client-server protocol which allows a user on one computer to transfer files to and from another computer over a TCP/IP network.

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GIF (Graphics Interchange Format)

A standard for digitized images compressed with the LZW algorithm, defined in 1987 by CompuServe (CIS). GIF files are limited to 256 colors.

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Homepage

The top-level entry point web page relating to an individual or institution. All other pages on a website are usually accessible by following links from the home page. Also the web page a user's web browser is configured to load each time it is started. This will typically default to the home page (sense 1, above) of the organization that produced or distributed the browser.

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HTML (HyperText Markup Language)

A set of tags and rules used in developing hypertext documents to be presented on the World Wide Web, allowing incorporation of text, graphics, sound, video, and hyperlinks. Internet browsers read HTML to know what they should display.

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HTTP (HyperText Transfer Protocol)

The client-server TCP/IP protocol used on the World Wide Web for the exchange of HTML documents.

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Hypertext

Text, in a form readable by a web browser, in which the reader may navigate from one passage to another by clicking on hyperlinks within the text.

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ISP (Internet Service Provider)

A company which provides other companies or individuals with access to, or presence on, the Internet. Most ISPs are also Internet Access Providers; extra services include help with design, creation and administration of World-Wide Web sites, training and administration of intranets and domain name registration.

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JavaScript

A simple, cross-platform, World Wide Web scripting programming language used to add interactive functions to HTML pages.

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JPEG (Joint Photographic Expert Group)

An image file format designed for compressing either full-color or grayscale digital images of “natural,” real-world scenes. It does not work so well on non-realistic images, such as cartoons or line drawings. JPEG does not handle compression of black-and-white (1 bit-per-pixel) images or moving pictures.

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K (Kilobyte)

A standard unit of measurement. A kilobyte is 2^10, or 1024 bytes.

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LAN (Local Area Network)

A data communications network that is geographically limited (typically to a 1 km radius) allowing easy interconnection of terminals, microprocessors, and computers within adjacent buildings. Ethernet and FDDI are examples of standard LANs.

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Megabyte (MB)

A standard unit of measurement. A megabyte is 2^20, or 1,048,576 bytes, which is equal to 1024 kilobytes.

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Modem (MOdulator + DEModulator)

A device that encodes digital computer signals into analog telephone signals and vice versa and allows computers to communicate over a phone line

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MPEG (Moving Pictures Experts Group)

Any of a group of computer file formats for the compression and storage of digital video and audio data.

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Network

Multiple computers and other devices connected together to share information.

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Online

Describes a system which is connected (generally electrically) to a larger network. Also decribes something available over the Internet.

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Operating system software

The low-level software which handles the interface to peripheral hardware, schedules tasks, allocates storage, and presents a default interface to the user when no application program is running. This software is generally specific to a type of computer (e.g. Windows 95, Windows XP, Mac OS X).

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PDF (Portable Document Format)

The native file format for Adobe Systems' Acrobat. PDF is the file format for representing documents in a manner that is independent of the original application software, hardware, and operating system used to create those documents. A PDF file can describe documents containing any combination of text, graphics, and images in a device-independent and resolution independent format. These documents can be one page or thousands of pages, very simple or extremely complex with a rich use of fonts, graphics, color, and images. To view a PDF file, you need Adobe Acrobat Reader, a free application distributed by Adobe Systems.

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Router

A device which forwards packets between networks. The forwarding decision is based on network layer information and routing tables, often constructed by routing protocols.

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RSS (Real Simple Syndication)

A family of document types for listing updates to a site. RSS documents (generally called "RSS feeds") are readable with RSS readers (generally called "aggregators") like BottomFeeder, or through aggregator functions incorporated into web browsers.

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Script

A file containing a list of user commands, allowing them to be invoked once to execute in sequence.

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SSL (Secure Sockets Layer)

A protocol that provides secure communications over the Internet using asymmetric key encryption. SSL is layered beneath application protocols such as HTTP, SMTP, and FTP and is layered above the connection protocol TCP/IP.

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T1

A very high bandwidth network path used to transmit a digital signal at 1.544 megabits per second.

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TCP/IP (Transmission Control Protocol/Internet Protocol)

The standard protocol now widely in use for computers to communicate on networks, especially the Internet.

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Upload

To transfer programs or data over a digital communications link from a smaller or peripheral "client" system to a larger or central "host" one.

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URL (Uniform Resource Locator)

A standard way of specifying the location of an object, typically a web page, on the Internet. (e.g. http://www.crocker.com)

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WAN (Wide Area Network)

A network, usually constructed with serial lines, extending over distances greater than one kilometer.

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Webmaster

The alias or role of the person(s) responsible for the development and maintenance of one or more web servers and/or some or all of the web pages at a website.

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Web site

Pages on the World Wide Web that are accessible from the same URL and typically reside on the same server.

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WWW (World Wide Web)

An information space on the Internet in which the items of interest, referred to as resources, are identified by global identifiers called uniform resource identifiers.

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XHTML (Extensible Hypertext Markup Language)

A reformulation of HTML 4.01 in XML. Being XML means that XHTML can be viewed, edited, and validated with standard XML tools. At the same time, it operates as well as or better than HTML 4 in existing HTML 4 conforming user agents.

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