Computer Science

Hacker
Also known as a "Cracker", a Hacker is a person who breaks into a site through a computer's security.

Half-Duplex
Half-Duplex can send transmissions both ways (send and receive), but only one at a time.

Hard Drives
High capacity internal magnetic disk for data storage and program files. Also called a fixed disk.

Hardware
The physical elements of the computer system.

Header
The portion of a packet that contains source and destination addresses, and other information. It precedes the actual data.

hit
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 2 graphics, 3 "hits" would occur at the server: 1 for the HTML page, and one for each of the graphics. Usually though, the number of visitors to a site are referred to as "hits."

HMA
High Memory Area

Home Page
The page that your browser is set to open when you logon. Also refers to the main (or home) page of a multiple page Web site. Sometimes spelled as one word (homepage).

Host
The computer on which a web site is physically located.

HOSTS and LMHOSTS
HOSTS and LMHOSTS are text files that are used to look up and resolve NetBIOS names to IP addresses.

HRR
Horizontal Refresh Rate - The speed at which the electron beam in a CRT completes one horizontal trace.

HTML
Hypertext Mark-up Language. HTML is not really a programming language, but a way to format text by placing marks around the text. For example HTML allows you to make a word bold or underline it. Early word processing programs used to work this way. HTML is the foundation for most web pages.

HTTP
Hypertext Transfer Protocol - The protocol used for moving hypertext files across the Internet. This is a very important protocol on the WWW, hence when you enter in URL the address starts with http://..

Hub
The center of a cabling system or a network with star topology architecture.

Hybrid Topology
A network topology that combines bus, star, or ring topologies.

Hypermedia
Media (such as pictures, videos, and audio), on a web page that links the user to another web page by clicking on the media.

Hypertext
Text on a web page that links the user to another web page. The hypertext, or links will usually be a different color than the other text on the page and is usually underlined.