Appendix Glossary H

In the left margin you will find links to the glossary categorised alphabetically. Some of the pages are quite long and may take a few moments to load if you use a modem. This glossary is always being updated.

Glossary - H

Hack - To alter a computer program or gain unauthorised entry into a program, computer, or computer system.

Hacker - Though the term has been associated primarily with people who endeavour to violate computer or software security in some manner, the primary definition refers to an individual who is exceptionally skilled as a computer programmer. The other common meaning for the word is someone who gains unauthorised entry into a computer system or software program for the sake of mischief or financial gain. In light of many of the malicious deeds and pranks being played of late, such as the malicious introduction of viruses via email, and the intentional crippling of large Websites such as Yahoo, the accepted use of the term is unfortunately becoming negative.

Half Duplex - The normal connection type of network interface cards on Ethernet set-ups. Data can only be received or transmitted at one time (not both).

Half Height - Standard drive size equivalent to half the vertical space of a 5.25-inch drive.

Handshake - The communication between two modems that indicates a connection is being made.

Hang - A kind of computer crash that makes communication between the keyboard and computer impossible with the exception of utilising the CTRL-ALT-DEL function. Doing so will offer the user the option to close the active application or reboot the computer.

Hard Copy - An actual printed paper copy of a computer document. A soft copy exists only on a computer monitor.

Hard Disk - A type of storage medium that retains data as magnetic patterns on a rigid disk, usually made of a magnetic thin film deposited on an aluminium platter. Because hard disks spin more rapidly than floppy disks, and the head flies closer to the disk, hard disks can transfer data faster and store more in the same volume. A hard drive is the mass storage device in your computer. Whenever you same a document, you save it to your hard disk. The hard disk stores pretty much everything you see on the screen.

Hard Drive Controller - This is the circuitry that tells the hard drive what to do.

Hard Error - A data error that persists when the disk is reread, usually caused by defects in the physical surface.

Hardware - Components of a computer system including monitors, hard drives, CD-ROMs, printers, modems, etc. The physical components of a computer system. It is controlled by the software. It is like driving a car: the hardware is the car itself; the software is the actual driving or instructions given the car by the driver to take it to where the driver wants to go.

Hardwired - 1. built in computer components that cannot easily be altered. 2. online copy that remains the same whenever a particular Web page is viewed.

Hayes Compatible - An industry standard among modems and products using command language developed by Hayes Microcomputer Products Inc. known as AT command set. Virtually all modems manufactured today are Hayes compatible.

HDA - Acronym for head disk assembly, typically a sealed unit.

Head - The tiny electromagnetic coil and metal pole used to create and read back the magnetic patterns on the disk. Also known as the read/write head.

Head Crash - Damage to a read/ write head and magnetic media, usually caused by sudden contact of the heads with the disk surface. Head crash also can be caused by dust and other contamination inside the HDA. High-capacity drive - By industry conventions, typically a drive of 500 megabytes or more.

Heap - A block of data storage space allocated to a programmer for writing a program or a specific program function.

Heat Sink - A component, typically zinc alloy, that dissipates heat. CPUs require heat sinks.

Heat Spreader - A sheath, usually aluminium, that covers an electronic device and dissipates heat.

Hexadecimal - Base 16. The numbering system goes as follows 1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11,etc., where F would equal 15 in base 10.

HFS - "Hierarchical File System" HFS is the file structure used when formatting a volume for use in the Macintosh operating system. When one formats any disk (including a CD-ROM) for use on a computer running the Macintosh operating system, the formatting is done in accordance with the file system standard called "HFS."

Hidden Files - Files not listed in the directory or easily accessible to users in operating systems. Files vital to the operation of a system are hidden so a user will not accidentally alter or delete them.

Hierarchical - A system of organisation similar to the chain of command in the military where the root of the hierarchy is the primary element in the system. Using the military example, the President is the leader of all of the armed forces, followed by the head of the joint chiefs of staff, then the top generals and admirals in the various branches of the military, etc. A similar system is used in categorising the data contained on a computer, beginning with a computer's root directories, then subdirectories, folders, and files.

High Density Disk - A floppy disk of high quality that is able to hold 1.44 MB (megabytes) of data and can only be used in high density diskette drives.

High Level Formatting - Formatting performed by the operating system's format program (for example, the DOS FORMAT program). Among other things, the formatting program creates the root directory, file allocation tables, and other basic configurations.

History - A folder included as part of a Web browser that shows a user the Websites that have been visited. For example, on Microsoft's Internet Explorer, the history file may be accessed by first clicking View on the menu bar then select Explore Bar, and finally, History. This will display the recently viewed Web pages. The user can set the number of days a Website's URL will stay in the history file.

Hit - The request from a browser for a Web page and the delivery of that page by a Web server. Strictly speaking, individual components of a page such as an isolated graphic, and a block of text are each considered a hit. Therefore, a page containing three pictures would be counted as at least three hits. Hits are used to determine the volume of traffic a Website receives.

Home - Reference position track for recalibration of the actuator, usually the outer track (Track 0).

Home page - 1. The first page loaded by your browser when you start up. 2. The main WWW document for a person, group, or organisation.

HomeRF - Yet another wireless networking "standard," endorsed by Intel, Compaq, Proxim and a handful of others. Promises throughput up to 1.6 MBps

Hop - A term used when counting components and wiring segments in an Ethernet network to determine whether Ethernet compliance has been met.

Host - A computer connected directly to the Internet or a server on a LAN. A service provider's computer is a host.

Host Adapter - A plug-in board or circuitry on the motherboard that acts as the interface between a computer system bus and the disk drive. Typically used with embedded controller drives such as SCSI and IDE.

Hosting - The act of storing files on a common server and making them available to their owner or others. "Hosting" in this context does not refer to one's ability to throw really great parties, despite the fact that nerds and geeks alike love to party down.

Hot Swapping - The ability to add and/or remove PC cards without restarting the computer to use the cards.

HTML - "Hypertext Markup Language" HTML is the language that is used to construct pages on the world wide web. Web pages themselves are individual text documents that use specialised"tags" or instructions to define how text and images are to appear on the screen. In order to be readable by a web browser, these text documents are formatted with the Hypertext Markup Language or "HTML." It is though the miracle of HTML that nerds all over the world can each have their own websites to tell all the other nerds about their favourite books, movies, and other websites. HTML (Hypertext Markup Language) is the set of "markup" symbols or codes inserted in a file intended for display on a browser such as Microsoft's Internet Explorer or Netscape Communicator. The markup tells the web browser how to display a web page's words and images for the user to see (e.g. bold, centre, underline text, where to insert the image, etc.). HTML is a subset of SGML (Standard Generalised Markup Language).

HTTP - "Hypertext Transfer Protocol" HTTP is the standard that makes the world wide web possible. Users of the Internet will be most familiar with this acronym as the first characters of any complete web address. The URL for every web page starts with the characters "http://" which are followed by the specific address of the site in question. By entering this string of letters and punctuation, a user is telling the browser software that protocol to be used is the Hypertext Transfer Protocol, and therefore the materials being accessed are part of the world wide web. HTTP is the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server, asking it to send a file (usually an HTML file) back to the Web browser on your computer.

Hub - Also referred to as a "repeater" or "concentrator", its primary function is to receive and send signals along the network between the nodes connected to it. For home users, hubs usually have 4-8 "ports" (or RJ-45 jacks) that connect cables coming from individual computers on the network.

Hypergraphic - In a World Wide Web document, a graphic image coded to form a link to another file. As with hypertext, if you click on a hypergraphic, you will jump to the linked file.

Hyperlink - Hyperlinks are the references to specific locations on the Internet that are embedded in HTML documents (or web pages) on the world wide web. Authors of web pages typically use hyperlinks to other pages within a site to guide users through their content. Hyperlinks are also used to provide users with an instant connection to a totally different site, such as the author's favourite page about nothing. As you should be able to see by the above example, hyperlinks are usually underlined and displayed in a different colour in the browser window.

Hypermedia - Hyperlinks on a Website that connect a user to video, sound and enhanced graphics.

Hypertext - Documents which contain embedded links (often underlined or otherwise differentiated from the rest of the text) which allow the user to easily move among different parts of the same document, or between documents.