Hacker - A person who is on a first-name basis with RAM, ROM, and the microprocessor. A person who'd rather write application programs than use store-bought programs.

Half-Bridge - A device used to connect two remote networks over a telecommunications link.

Half-Duplex Modem - A modem that does not echo information it receives from the sending computer.

Half-Router - A router that is used to connect two or more remote networks over a telecommunications link. Each network is connected to a router, which in turn is connected to a modem. This combination of two half-routers serves, in effect, as a single routing unit. Also called a remote router.

Hand Controls - Computer accessories used mainly in games to move creatures and objects. Also used in simulation applications.

Handshaking - Handshaking is a method of controlling the speed of data transfer by signaling when each side of the connection is ready to receive data. This ensures that both sides can keep up and no data is lost. In hardware handshaking, the modem and computer exchange RTS and CTS signals over the connecting cable. In software handshaking, the modem and computer exchange XON and XOFF characters to start and stop data transfer.

Hard Disk-or Hard Disk Drive, or Hard Drive - Large-capacity, permanent storage for the computer used for storing applications and files, made of multiple disks housed in a rigid case.

Hardware - Those parts of the computer that you can see and touch. The computer and the machines that attach to it-the disk drive, printer, and other peripheral devices.

Header - Text that appears at the top of every page or every other page of a document. A footer is text that appears at the bottom of every page or every other page in a document.

HFS+ - hierarchical file system plus, also known as Mac OS Extended format, a data storage format.

- hierarchical file system, also known as Mac OS Standard format, a data storage format.

HID - human interface device, a class of USB devices.

High Definition Video - Refers to any of a wide range of video formats, including the 24P format, providing a higher quality image than standard video. Enhancements can include increased resolution, a wider aspect ratio, and progressive scanning.

High Resolution-A graphics mode that can display information using a rectangular array of 280 horizontal by 192 vertical dots.

High-Density Floppy Disk - A 1.4-megabyte floppy disk; the associated drive was commonly used in older Macintosh models.

Highlight - To select by clicking once on an icon or by clicking and dragging the insertion point across text in a document.

Hinting - Hinting creates a track for each streamable media track in the file that tells QuickTime Streaming Server how and when to deliver each frame of media. The hinting process performs in advance the required calculations, allowing QTSS to serve up a larger number of streams. Hinting also allows new codecs to be used without the need to upgrade the server.

Home Computer
- A computer, like the Apple IIgs, that is small enough and affordable enough to have in your house. When you take a home computer to the office, it becomes a productivity tool.

Home Control Device - A device that can regulate the temperature of your home, turn lamps on and off, or monitor smoke detectors and burglar alarms.

Home Directory - A folder for a user's personal use. Mac OS X also uses the home directory, for example, to store system preferences and managed user settings for MacOS X users.

Home Finance Application - An application that helps with budgeting, portfolio management, tax planning, and so on. Like a spreadsheet, only easier to use.

Home Row - The row of keys on the keyboard where the fingers of touch typists rest when they aren't reaching for other keys. In the standard keyboard layout, the home row contains A, S, D, F, G, and so on. In the Dvorak keyboard layout, the home row contains what August Dvorak determined were the most frequently used keys A, O, E, U, I, and so on.

Hop - A unit count between networks on an internet. Signifies one router away.

HTML-HyperText Markup Language - A set of simple tags that tells a computer how to display the text, graphics, and other objects that comprise a Web page.

HTTP Hypertext Transfer Protocol - An application protocol that defines the set of rules for linking and exchanging files on the World Wide Web.

Hz - Hertz.