H


H.323

The ITU-T standard for multimedia communications over networks that do not provide a guaranteed quality of service (QoS). This standard provides specifications for workstations, devices, and services to carry real-time video, audio, and data or any combination of these elements. See also International Telecommunication Union - Telecommunication [Standardization Sector] (ITU-T); Quality of Service (QoS).

hardware abstraction layer (HAL)

A thin layer of software provided by the hardware manufacturer that hides, or abstracts, hardware differences from higher layers of the operating system. By means of the filter provided by the HAL, different types of hardware look alike to the rest of the operating system. This allows the operating system to be portable from one hardware platform to another. The HAL also provides routines that allow a single device driver to support the same device on all platforms.

Hardware Compatibility List (HCL)

A hardware list that Microsoft compiles for a specific product. The Windows HCL, which is posted on the Web, lists the hardware devices and computer systems that are compatible with specific versions of Windows.

hardware configuration

Resource settings that have been allocated for a specific device. Each device on your computer has a hardware configuration, which can consist of interrupt request (IRQ) lines, DMA, an I/O port, or memory address settings. See also direct memory access (DMA); input/output (I/O) port.

hardware decoder

A type of digital video disc (DVD) decoder that allows a DVD drive to display movies on your computer screen. A hardware decoder uses both software and hardware to display movies. See also DVD decoder; DVD drive; software decoder.

hardware malfunction message

A character-based, full-screen error message displayed on a blue background. It indicates that the microprocessor detected a hardware error condition from which the system cannot recover.

head

The mechanism that reads data from and writes data to a hard disk. Hard disks use one head for each side of each platter. The heads are attached to a common head-movement area, so that all heads move in unison. The heads are always positioned over the same logical track on each side of each platter. See also track.

high byte

The byte containing the most significant bits (bits 8 through 15) in a 2-byte grouping representing a 16-bit (bits 0 through 15) value.

hop

In data communications, one segment of the path between routers on a geographically dispersed network. A hop is comparable to one "leg" of a journey that includes intervening stops between the starting point and the destination. The distance between each of those stops (routers) is a communications hop.

Hosts file

A local text file in the same format as the 4.3 Berkeley Software Distribution (BSD) UNIX /etc/hosts file. This file maps host names to IP addresses, and it is stored in the \%Systemroot%\System32\Drivers\Etc folder. See also systemroot.

HTML

See definition for Hypertext Markup Language (HTML).

HTML+TIME

A feature in Microsoft Internet Explorer 5 that adds timing and media synchronization support to HTML pages. Using a few Extensible Markup Language (XML)-based elements and attributes, you can add images, video, and sounds to an HTML page, and synchronize them with HTML text elements over a specified amount of time. In short, you can use HTML+TIME technology to quickly and easily create multimedia-rich, interactive presentations, with little or no scripting.

HTTP

See definition for Hypertext Transfer Protocol (HTTP).

hubbed mode

A mode in which the ARP/MARS provides ATM addresses to requesting clients in the form of a multicast server (MCS) list value. In this mode, the ARP/MARS acts as a multicast server, providing active forwarding of all multicast and broadcast traffic destined for IP addresses contained within the ranges specified in the list. See also Asynchronous Transfer Mode (ATM); IP address.

Human Interface Device (HID)

A firmware specification that is a new standard for input and output devices such as drawing tablets, keyboards, USB speakers, and other specialized devices designed to improve accessibility. See also universal serial bus (USB).

Hypertext Markup Language (HTML)

A simple markup language used to create hypertext documents that are portable from one platform to another. HTML files are simple ASCII text files with codes embedded (indicated by markup tags) to denote formatting and hypertext links. See also American Standard Code for Information Interchange (ASCII).

Hypertext Transfer Protocol (HTTP)

The protocol used to transfer information on the World Wide Web. An HTTP address (one kind of Uniform Resource Locator [URL]) takes the form: http://www.microsoft.com/




Microsoft Windows XP Professional Resource Kit 2003
Microsoft Windows XP Professional Resource Kit 2003
ISBN: N/A
EAN: N/A
Year: 2005
Pages: 338
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