demand paging-through-digitize
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time
demand paging
n. The most common implementation of virtual memory, in which pages of data are read into main memory from an auxiliary storage device only in response to interrupts that result when software requests a memory location that the system has saved to auxiliary storage and reused for other purposes. See also paging, swap (definition 2), virtual memory.
demo
n. 1. Short for demonstration. A partial or limited version of a software package distributed free of charge for advertising purposes. Demos often consist of animated presentations that describe or demonstrate the program's features. See also crippled version. 2. A computer in a store that is available for customers to test, to see if they wish to buy it.
demodulation
n. In communications, the means by which a modem converts data from modulated carrier frequencies (waves that have been modified in such a way that variations in amplitude and frequency represent meaningful information) over a telephone line to the digital form needed by a computer, with as little distortion as possible. Compare modulation (definition 1).
demonstration program
or demo program n. 1. A prototype that shows the on-screen look and sometimes the proposed capabilities of a program under development. See also prototyping. 2. A scaled-down version of a proprietary program offered as a marketing tool.
DES
n. Acronym for Data Encryption Standard. A specification for encryption of computer data developed by IBM and adopted by the U.S. government as a standard in 1976. DES uses a 56-bit key. See also encryption, key (definition 3).
descending sort
n. A sort that arranges items in descending order--for example, with Z preceding A and higher numbers preceding lower ones. See also alphanumeric sort. Compare ascending sort.
deselect
vb. To reverse the action of selecting an option, a range of text, a collection of graphical objects, and so on. Compare select.
desk accessory
n. A type of small program on Macintosh computers and in windowing programs for IBM and PC-compatible machines that acts as the electronic equivalent of a clock, calendar, calculator, or other small appliance found on a typical desktop. Desk accessories are conveniences that can be activated when needed and then either put away or moved to a small part of the screen. A special type of desk accessory, a control panel, provides the user with the ability to change the date and time as well as to control screen colors, mouse movements, and other parameters. Also called desktop accessory. See also control panel. Acronym: DA.
desktop
n. An on-screen work area that uses icons and menus to simulate the top of a desk. A desktop is characteristic of the Apple Macintosh and of windowing programs such as Microsoft Windows. Its intent is to make a computer easier to use by enabling users to move pictures of objects and to start and stop tasks in much the same way as they would if they were working on a physical desktop. See also graphical user interface.
desktop computer
n. A computer that fits conveniently on the surface of a business desk. Most personal computers as well as some workstations can be considered desktop computers. Compare portable computer.
desktop conferencing
n. The use of computers for simultaneous communication among geographically separated participants in a meeting. This communication may include input to and display from application programs as well as audio and video communication. See also data conferencing, teleconferencing, video conferencing.
desktop publishing
n. The use of a computer and specialized software to combine text and graphics to create a document that can be printed on either a laser printer or a typesetting machine. Desktop publishing is a multiple-step process involving various types of software and equipment. The original text and illustrations are generally produced with software such as word processors and drawing and painting programs and with photograph- scanning equipment and digitizers. The finished product is then transferred to a page-makeup program, which is the software most people think of as the actual desktop publishing software. This type of program enables the user to lay out text and graphics on the screen and see what the results will be; for refining parts of the document, these programs often include word processing and graphics features in addition to layout capabilities. As a final step, the finished document is printed either on a laser printer or, for the best quality, by typesetting equipment.
desktop video
n. The use of a personal computer to display video images. The video images may be recorded on video tape or on a laser disc or may be live footage from a video camera. Live video images can be transmitted in digital form over a network in video conferencing. Acronym: DTV.
destination
n. The location (drive, folder, or directory) to which a file is copied or moved. Compare source (definition 1).
detection
n. Discovery of a certain condition that affects a computer system or the data with which it works.
developer's toolkit
n. A set of routines (usually in one or more libraries) designed to allow developers to more easily write programs for a given computer, operating system, or user interface. See also library (definition 1), toolbox.
development cycle
n. The process of application development from definition of requirements to finished product, including the following stages: analysis, design and prototyping, software coding and testing, and implementation.
device
n. A generic term for a computer subsystem. Printers, serial ports, and disk drives are often referred to as devices; such subsystems frequently require their own controlling software, called device drivers. See also device driver.
device address
n. A location within the address space of a computer's random access memory (RAM) that can be altered either by the microprocessor or by an external device. Device addresses are different from other locations in RAM, which can be altered only by the microprocessor. See also device, input/output, RAM.
device dependence
n. The requirement that a particular device be present or available for the use of a program, interface, or protocol. Device dependence in a program is often considered unfortunate because the program either is limited to one system or requires adjustments for every other type of system on which it is to run. Compare device independence.
device driver
n. A software component that permits a computer system to communicate with a device. In most cases, the driver also manipulates the hardware in order to transmit the data to the device. However, device drivers associated with application packages typically perform only the data translation; these higher-level drivers then rely on lower-level drivers to actually send the data to the device. Many devices, especially video adapters on PC-compatible computers, will not work properly--if at all--without the correct device drivers installed in the system.
device independence
n. A characteristic of a program, interface, or protocol that supports software operations that produce similar results on a wide variety of hardware. For example, the PostScript language is a device-independent page description language because programs issuing PostScript drawing and text commands need not be customized for each potential printer. Compare device dependence.
device manager
n. A software utility that allows viewing and changing hardware configuration settings, such as interrupts, base addresses, and serial communication parameters.
Device Manager
n. In Windows 95, a function within the System Properties utility that indicates device conflicts and other problems and allows a user to change the properties of the computer and each device attached to it. See also property, property sheet.
device name
n. The label by which a computer system component is identified by the operating system. MS-DOS, for example, uses the device name COM1 to identify the first serial communications port.
DHCP
n. Acronym for Dynamic Host Configuration Protocol. A TCP/IP protocol that enables a network connected to the Internet to assign a temporary IP address to a host automatically when the host connects to the network. See also IP address, TCP/IP. Compare dynamic SLIP.
Dhrystone
n. A general-performance benchmarking test, originally developed by Rheinhold Weicker in 1984 to measure and compare computer performance. The test reports general system performance in dhrystones per second. It is intended to replace the older and less reliable Whetstone benchmark. The Dhrystone benchmark, like most benchmarks, consists of standard code revised periodically to minimize unfair advantages to certain combinations of hardware, compiler, and environment. Dhrystone concentrates on string handling and uses no floating-point operations. Like most benchmarking tests, it is heavily influenced by hardware and software design, such as compiler and linker options, code optimizing, cache memory, wait states, and integer data types. See also benchmark2. Compare sieve of Eratosthenes, Whetstone.
DIA
n. Acronym for Document Interchange Architecture. A document exchange guideline used in IBM's Systems Network Architecture (SNA). DIA specifies methods of organizing and addressing documents for transmission between computers of different sizes and models. DIA is supported by IBM's Advanced Program-to-Program Communication (APPC) and by Logical Unit (LU) 6.2, which establish the capabilities and types of interactions possible in an SNA environment. See also DCA (definition 1), SNA.
dialect
n. A variant of a language or protocol. For example, Transact-SQL is a dialect of structured query language (SQL).
dialog
n. 1. In computing, the exchange of human input and machine responses that forms a "conversation" between an interactive computer and the person using it. 2. The exchange of signals by computers communicating on a network.
dialog box
n. In a graphical user interface, a special window displayed by the system or application to solicit a response from the user. See also windowing environment. Compare integrator.
dial-up
adj. Of, pertaining to, or being a connection that uses the public switched telephone network rather than a dedicated circuit or some other type of private network.
dial-up access
n. Connection to a data communications network through a public switched telecommunication network.
dial-up service
n. A telephone connection provider for a local or worldwide public switched telephone network that provides Internet or intranet access, advertisement via a Web page, access to news services, or access to the stock market and other resources.
DIB
n. 1. Acronym for device-independent bit map. A file format designed to ensure that bitmapped graphics created using one application can be loaded and displayed in another application exactly the way they appeared in the originating application. See also bitmapped graphics. 2. Acronym for Directory Information Base. A directory of user and resource names in an X.500 system. The DIB is maintained by a Directory Server Agent (DSA). Also called white pages.
DIBengine
n. Software, or a combination of hardware and software, that produces DIB files. See also DIB (definition 1).
digit
n. One of the characters used to indicate a whole number (unit) in a numbering system. In any numbering system, the number of possible digits is equal to the base, or radix, used. For example, the decimal (base-10) system has 10 digits, 0 through 9; the binary (base-2) system has 2 digits, 0 and 1; and the hexadecimal (base-16) system has 16 digits, 0 through 9 and A through F.
digital
adj. 1. Related to digits or the way they are represented. 2. In computing, analogous to binary because the computers familiar to most people process information coded as combinations of binary digits (bits). Compare analog.
digital audio tape
n. A magnetic tape storage medium for recording digitally encoded audio information. Acronym: DAT.
digital audio/video connector
n. An interface on some high-end video cards or TV tuner cards that allows the simultaneous transmission of digital audio and video signals. Also called DAV connector. See also interface (definition 3), video adapter.
digital camera
n. A type of camera that stores photographed images electronically instead of on traditional film. A digital camera uses a CCD (charge-coupled device) element to capture the image through the lens when the operator releases the shutter in the camera; circuitry within the camera then stores the image captured by the CCD in a storage medium such as solid-state memory or a hard disk. After the image has been captured, it is downloaded by cable to the computer using software supplied with the camera. Once stored in the computer, the image can be manipulated and processed much like the image from a scanner or related input device. See also charge-coupled device.
digital data transmission
n. The transfer of information encoded as a series of bits rather than as a fluctuating (analog) signal in a communications channel.
digital display
n. A video display capable of rendering only a fixed number of colors or gray shades. Examples of digital displays are IBM's Monochrome Display, Color/Graphics Display, and Enhanced Color Display. See also CGA, EGA, MDA. Compare analog display.
digital photography
n. Photography by means of a digital camera. Digital photography differs from conventional photography in that a digital camera does not use a silver halide-based film to capture an image. Instead, a digital camera captures and stores each image electronically. See also digital camera.
digital signal
n. A signal, such as one transmitted within or between computers, in which information is represented by discrete states--for example, high and low voltages--rather than by fluctuating levels in a continuous stream, as in an analog signal.
digital signal processor
n. An integrated circuit designed for high-speed data manipulation and used in audio, communications, image manipulation, and other data acquisition and data control applications. Acronym: DSP.
digital signature
n. A personal authentication method based on encryption and secret authorization codes used for "signing" electronic documents.
Digital Simultaneous Voice and Data
n. A modem technology, patented by Multi-Tech Systems, Inc., that allows a single telephone line to be used for conversation together with data transfer. This is accomplished by switching to packet-mode communications when the need for voice transfer is detected; digitized voice packets are then transferred along with data and command packets. Acronym: DSVD.
digital subscriber line
n. An ISDN BRI (Basic Rate Interface) line or channel. See also BRI, ISDN. Acronym: DSL.
digital-to-analog converter
n. A device that translates digital data to an analog signal. A digital-to-analog converter takes a succession of discrete digital values as input and creates an analog signal whose amplitude corresponds, moment by moment, to each digital value. Compare analog-to-digital converter. Acronym: DAC.
digital video disc
n. The next generation of optical disc storage technology. With digital video disc technology, video, audio, and computer data can be encoded onto a compact disc (CD). A digital video disc can store greater amounts of data than a traditional CD. A standard single-layer, single-sided digital video disc can store 4.7 GB of data; a two-layer standard increases the single-sided disc capacity to 8.5 GB. Digital video discs can be double-sided with a maximum storage of 17 GB per disc. A digital video disc player is needed to read digital video discs; this player is equipped to read older optical storage technologies. Advocates of the digital video disc intend to replace current digital storage formats, such as laser disc, CD-ROM, and audio CD, with the single digital format of the digital video disc. Also called digital versatile disc. See also digital video disc-ROM. Acronym: DVD.
digiterati
n. The digital counterpart of literati, an undefined collection of individuals recognized as knowledgeable, hip, or up-to-date regarding all things digital.
digitize
vb. To convert any continuously varying (analog) source of input, such as the lines in a drawing or a sound signal, to a series of discrete units represented in a computer by the binary digits 0 and 1. Analog-to-digital converters are commonly used to perform this translation. See also aliasing, analog-to-digital converter.
A/B Switch box ~ America On-line AMI BIOS ~ Arithmetic Operation ARP ~ AVI Backbone ~ Bit Image Bit Map ~ Boot Disk Boot Drive ~ Bytes Per Inch C++ ~ Carrier Frequency carrier system ~ certification CGI ~ Chooser extension cipher ~ Clipper Chip clock ~ color color bits ~ communications satellite communications server ~ computer security CON ~ copy copy program ~ cycle time daemon ~ defragmentation demand paging ~ digitize DikuMUD ~ disk disk buffer ~ Document Style Semantics and Specification Language document window ~ dynamic Web page Easter egg ~ erase erase head ~ ezine F2F ~ finger2 firewall ~ font suitcase footer ~ FYI Game Control Adapter ~ GUI HAL ~ hot key1 hot key2 ~ Hz i486DX ~ internal modem internet ~ ISO 9660 ISO/OSI model ~ just-in-time K1 ~ knowledge base L1 cache ~ LU luggable computer ~ LZW compression MAC ~ MILNET mime ~ msec MTBF ~ MYOB named anchor ~ network drive Network File System ~ number crunching object ~ overwrite mode P5 ~ PC/XT keyboard PDA ~ pipeline processing piracy ~ preventive maintenance preview ~ pwd quasi-language ~ QWERTY keyboard R&D ~ registration marks Registry ~ RFI RF shielding ~ run-time library SAA ~ server error server push-pull ~ soft return software ~ style sheet stylus ~ System T1 ~ ToggleKeys token ~ typography UART ~ uupc V.120 ~ view2 viewer ~ VxD w3 ~ WinG WINS ~ WWW X.25 ~ X Windows Yahoo! ~ yotta- Z39.50 standard ~ Zulu time