Quick Search

Advanced Search

H CKInfo Items

Computer Knowledge information pages for terms starting with the letter H.

HAL - Hardware Abstraction Layer

(hal) An operating system component that lets programmers write device-independent code without the overhead normally seen with an API; an interface that might otherwise be used. More Information HAL Discussion Microsoft Definition Troubleshoot HAL

HD - High Density

(H-D) A term applied to many things but, originally, in computers it was applied to the storage density of floppy disks. First, there was single density, then double density, and high density increased the 5.25-inch floppy to 1.2MB and 3.5-inch fl...

HDD - Hard Disk Drive

(H-D-D) A general term used to describe disks that record data onto fixed platters spinning in an environmentally-controlled container. Hard disks have generally fast access times and connect to the computer via either IDE or SCSI interfaces. The ...

HDLC - High-level Data Link Control

(H-D-L-C) An OSI data link layer protocol that allows devices to both control data flow and correct data errors. HDLC sessions can be normal unbalanced (secondary only responds to a primary), asynchronous (secondary can also contact primary), asyn...

HDML - Handheld Device Markup Language

(H-D-M-L) A language that pre-dates Wireless Markup Language (WML), a language used to design Wireless Access Protocol (WAP) Web pages. More Information HDML FAQ

HDR - High Data Rate

(H-D-R) High speed data technology from Qualcomm. More Information HDR Overview

HDTV - High-Definition Television

(H-D-T-V) As the name implies, a form of television that increases definition (resolution) over current standards. HDTV uses digital signals versus the current analog standard. There are several picture sizes in the standard from a digital version...

HFS - Hierarchical Filing System

(H-F-S) The name for a filing system organized in layers. A directory tree would represent one type of HFS. More Information Macintosh HFS Page

HMA - High Memory Area

(H-M-A) The first 64K (minus 16 bytes) of extended memory (the 64K directly above the one megabyte point on an MS-DOS/Windows computer). The HMA is under the control of the driver HIMEM.SYS. The Intel 8086 and 8088 CPUs could only handle 1MB of me...

HMD - Head-Mounted Display

(H-M-D) A virtual reality headset containing small displays for the eyes, audio output for the ears, and, often, head-tracking equipment to allow user feedback and system response. More Information WearComp Papers

Recent Blogs