HALFTONE IMAGE

An image reproduced through a special screen made up of dots of various sizes to simulate shades of gray in a photograph. Typically used for newspaper or magazine reproduction of images.

HANDSHAKING

Handshaking is an exchange of signaling information between two communications systems. Handshaking establishes how the two systems will transmit data. A procedure carried out when establishing a connection between two data communications devices prior to any data transfer, communications synchronizing technique using two signals: (1) ready? (2) yes/no acknowledgement.

HARD COPY

In imaging usually used to describe anything on paper. Computer output that is produced on a permanent medium, generally paper.

HARD DISK

A hard disk is a magnetic storage device consisting of multiple spinning platters (disks), each with its own read write heads. Hard disk drives have a much higher storage capacity (up to a gigabyte or more) than floppy disks. They also have a much faster access time and higher transfer rate than floppy disk drives. A rigid circular platter coated with magnetic material. A type called a "Winchester" disk is contained in a disk drive unit that is permanently sealed to keep out dust and other contaminants. It has much greater storage capacity and can operate at faster speeds than a floppy disk of similar size.

HARDWARE

The 'nuts and bolts' of the computer, that includes the monitor, CPU, printers, disc drives, and etc.

HARDWIRED

Circuits that are permanently interconnected to perform a specific function, as distinct from circuits addressed by software in a program and, therefore, capable of performing a variety of functions, albeit more slowly. Also used to describe a non-switched connection between devices.

HCFA

Health Care Financing Administration.

HDTV (HIGH DEFINITION TELEVISION)

New video "standard" that will resolve 1,125 lines in the United States instead of the traditional 525 lines of the NTSC standard. In Europe and the Far East, the number of scan lines varies.

HEADER

The portion of a message, preceding the actual data, containing source and destination address and error-checking fields.

HEADER AREA

Portion of the transaction set which contains preliminary information that pertains to the entire transaction set, such as date, company name, address, terms, etc.

HEALTH CARE FINANCING ADMINISTRATION (HCFA)

Part of the United States Government Department of Health and Human Services, this group is responsible for national administration and guidance for Medicare and Medicaid programs.

HERTZ (HZ)

A unit of frequency. Hertz is used, for example, to describe the periodic properties of acoustic, electrical, and optical signals. Also used to describe refresh rate of monitors. One hertz is equal to one cycle per second.

HEXADECIMAL

Numbering system that uses 16 digits: 0, 1,2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. A base 16 numbering system.

HIERARCHICAL FILE STRUCTURE

A format for storing hierarchical files. Each unit of analysis has its own record structure or record type. Different units of analysis do not necessarily have the same number of bytes or characters as the records for other units of analysis. In order to give such a file a common physical record length, short logical records are typically "padded" with blanks so that they will all be the same physical record length. A hierarchical file can also be stored in a rectangular file. Typically, the hierarchical file structure is more space efficient but more difficult to use.

HIGH RESOLUTION

A quality of video graphics display systems or printers capable of producing images in great detail.

HIGH-LEVEL LANGUAGE

A programming language resembling natural language with powerful instructions, which require either a compiler or interpreter.

HIGHLIGHT

To make an object 'shaded' so that it is distinguished from other objects on a display screen or hard-copy printout.

HIGH-RESOLUTION VERSION

Version of the composite displayed on screen in the PIE window when the composite is being assembled. Shows exactly how the composite will look when it's printed.

HISTOGRAM

A bar graph analysis tool that can be used to identify contrast and dynamic range image problems. Histograms are found in most software programs that are used to manipulate digital images.

HIT

As used in reference to the World Wide Web, Hit means 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 3 graphics, 4 hits would occur at the server: for the HTML page and one for each of the 3 graphics. Hits are often used as a very rough measure of load on a server, e.g. "Our server has been getting 300,000 hits per month." Because each hit can represent anything from a request for a tiny document (or even a request for a missing document) to a request that requires some significant additional processing (such as a complex search request), the actual load on a machine from 1 hit is almost impossible to define.

HITS

The number of documents your program finds when you do a query.

HLLAPI

(High Level Language Application Program Interface) Used in an IBM environment, HLLAPl is a PC-based package that is used for creating interfaces between mainframes and PC applications. HLLAPl was designed specifically for use with high-level programming languages, such as C, Pascal, and BASIC.

HOLLERITH CARD

A punched hole card used for storing information for input into the computer. Aperture cards are a form of Hollerith card with a microfilmed image included.

HOME OFFICE

An office responsible for directing or managing two or more, but not necessarily all, segments of an organization. It typically establishes policy for and provides guidance to, the segments in their operations. It usually performs management, supervisory or administrative functions and may also perform service functions in support of the operations of the various segments. An organization, which has intermediate levels, such as groups, may have several home offices, which report to a common home office. An intermediate organization may be both a segment and a home office.

HOME PAGE

The term used to describe the first page or normal first point of access, of a web site. This page normally describes the site and should provide an index to the information or services provided by the site.

HOP COUNT

In message or packet routing, a hop is a transmission between two machines, which may be nodes or routers, depending on the size of the network or inter-network across which transmissions must go. In network routing, the number of nodes or routers through which a packet must (or may) pass in going from the source to the destination is called the hop count.

HOST

In the mainframe and minicomputer environments, a host or host computer is a machine that provides processing capabilities for attached terminals or nodes. The term used in the Internet community to describe any device attached to the network that provides application level service (i.e., a machine that one can log in to and do useful work). A router is not a host. Any computer on a network that is a repository for services available to other computers on the network. It is quite common to have one host machine provide several services, such as WWW and USENET.

HOST COMPUTER

In the context of networks, a computer that directly provides service to a user. In contrast to a network server, which provides services to a user through an intermediary host computer.

HOT FILE OR ITEM

Also known as a derogatory file or negative file. This refers to an item that is an exception, an account that should not be processed, generally due to insufficient funds or a closed account. This is critical in the case of a foreclosed mortgage, for example.

HOT KEY

In general, a hot key is a keystroke or keystroke combination that causes a particular action or function to be executed, usually regardless of the current state of a program or process.

HTML

Hypertext Markup Language.

HTML (HYPERTEXT MARKUP LANGUAGE)

An encoding format for linking and identifying electronic documents and used to deliver information on the World Wide Web. May be superseded by XML in the future.

HTTP ( HYPERTEXT TRANSFER PROTOCOL.)

The technology required for using hypertext. The beneficial feature of this text is that it allows the reader to follow links to different places in the document or to other related documents. See Hypertext Markup Language {HTML).

HUB

A hub is a network component that serves as a common termination point for multiple nodes and that can relay signals along the appropriate paths.

HUE

A term used to describe the entire range of colors of the spectrum; hue is the component that determines just what color you are using. In gradients, when you use a color model in which hue is a component, you can create rainbow effects.

HYBRID

A combination of technologies whose combined sum is a breed of the technology.

HYPERLINK

A pointer that when chosen displays the item to which it points. It typically takes the form of a button or highlighted text that points to related text, picture, video or audio. Hyperlinks allow non-linear exploration of media that contain them.

HYPERLINKS

Allow you to 'link' any document stored in a database with any other document. You can link a spreadsheet to an image, a database to a graphic, or a word processing file to a site on the World Wide Web. You can then navigate from one related document to another, simply by clicking on the hyperlinks.

HYPERMEDIA

Media (such as text, graphics, video, audio) that contain hyperlinks.

HYPERTEXT

Generally, any text that contains "links" to other documents. Words or phrases in the document which can be chosen by a reader and which cause another document to be retrieved and displayed.

HYPERTEXT MARKUP LANGUAGE (HTML)

The language used to develop pages for viewing on the World Wide Web. It has evolved from the print formatting standard, SGML, It enables web browsers to present information on the screen as the page designer intended preserving formats, permitting display of static and moving images and offering sound reproduction. The key feature is its ability to carry links, frequently described as hot links, to other pages both on the current web site and other sites.

HYPERTEXT TRANSFER PROTOCOL

Extremely fast protocol used for network file transfers in the WWW environment. Requires a HTTP client program on one end and an HTTP server program on the other end.