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hard drive: The place on a computer where data is stored and retrieved.

hardware cache: High-speed, temporary, chip-based storage that offers faster access time than CD-ROM hardware. By placing data in the hardware cache, you minimize the CD-ROM system's waiting time. Hardware cache speeds up access to the CD and the CD's performance.

headroom: The amount of gain an amplifier can produce before distorting.

hertz: A unit used to measure frequency in cycles/seconds.

host: Any computer on a network that is a repository for services available to other computers on the network.

HTML (hypertext markup language): The document format used to build pages on the World Wide Web. HTML tags, or codes, define the structure and layout of a Web document. There are hundreds of tags used to format and lay out a webpage. For instance, is used to make bold text and

denotes a new paragraph. HTML tags also specify hypertext links , allowing Web designers to direct users to other Web addresses or URLs.

HTTP (hypertext transfer protocol):The underlying communications protocol used to connect servers on the World Wide Web. For example, when you enter a URL in your browser, the browser sends an HTTP command to the Web server directing it to retrieve and transmit the requested page.

hub: Hardware used to network computers together (usually over an Ethernet connection). Its a small box with five or more RJ-45 connectors that accept cables from individual computers.

hyperlink: An icon or text element in a document that serves as a connection to another place in the same document or to an entirely different document. Hyperlinks are the foundation of hypertext systems, including the World Wide Web.

hypertext: Any text that contains links to other documents. When users click on hyperlinked text, another document is retrieved and displayed.

ICANN (Internet Corporation for Assigned Names and Numbers): A nonprofit, private corporation responsible for overseeing the following aspects of the World Wide Web: assigning space for IP addresses, managing the domain name system, and taking care of the root server system. Jon Postel created ICANN in 1998 in response to a call from the US Department of Commerce for a private sector, not-for-profit organization to manage r the Internet name and address system.
IDE (intelligent [or integrated] drive electronics): IDE connects mass storage devices such as hard drives or CD-ROMs to a computer.

in-line console: A type of mixing console that houses the monitor circuits within the same modules as the channel circuit. Most modern consoles are constructed this way.

insert: An input jack on an audio device that is used to route in audio signals from other devices.

IP address: The identifying address of a computer or device attached to a TCP/IP network. TCP/IP networks use IP addresses to route messages to their proper destinations. The IP address is written as four sets of numbers separated by periods. For an isolated network, IP addresses may be assigned at random provided each one is unique. However, if the private network is to be connected to the Internet, registered IP addresses (called Internet addresses) must be used, in order to avoid duplicates. Available unregistered addresses are becoming scarce under the three class (A, B and C) system of assigning addresses, so it is being replaced by the classless CIDR (Classles Inter-Domain Routing) system.

IRC (Internet relay chat): A system that allows people to have live conversations over the Internet. You can get on one of hundreds of available IRC channels, and whatever messages you type are seen by everyone on that channel. It was the first chat system to allow more than two people at a time to have a discussion.

ISDN (integrated services digital network): A digital communication system that can transmit voice or packet data over a regular phone line at rates between 64 Kbps and 256 Kbps. (Most home service maxes out at 128 Kbps.)

ISP (Internet service provider): An organization that supplies you with access the Internet for a fee.

Java: A programming language that is particularly useful on the Internet. Java was created and licensed by Sun Microsystems and is typically used to provide interactivity.

JavaScript: JavaScript has nothing to do with Java. This confusion was created by Netscape, which parasitically named the scripting language for its browser "JavaScript" to capitalize on the success of the Java programming language. Java, the programming language, is what's called a compiled language. It's written using English-language words and then translated by the computer into something that the computer can understand. Script is written in English as well, but is only understood and translated by the browser, not the computer itself. JavaScript is basically an advance on HTML coding that is used to provide functionality in webpages -- rollovers, pull-down menus, and so on.

JPEG (Joint Photographic Experts Group): Pronounced "jay-peg," JPEG is an ISO/ITU standard for compressing still images. Using discrete cosine transform, it provides lossy compression (you lose some data from the original image) with ratios up to 100:1 and higher. It depends on the image, but ratios of 10:1 to 20:1 may provide little noticeable loss. The more the loss can be tolerated, the more the image can be compressed. Compression is achieved by dividing the picture into tiny pixel blocks, which are halved over and over until the appropriate ratio is achieved. JPEG is implemented in software and hardware, with the latter providing sufficient speed for real-time, on-the-fly compression.

kernel: The central part of the Linux operating system that oversees all other operations. It loads first and stays in the memory throughout the operation of the OS.

kilobyte: In decimal systems, kilo stands for 1,000, but in binary systems, a kilo is 1,024 (2 to the 10th power). Technically, a kilobyte is 1,024 bytes, but it is often used loosely as a synonym for 1,000 bytes.

Don't see the word you want? Let us know at techglossary@techtv.com. For links to other resources, go back to the glossary's start page.

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