0-9 A B C D E F G H I J K L M N O P Q R S T U V W XYZ

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display:
(1) A visual presentation of data. (2) To present data visually.

display and printing calculator:
A calculator that provides the data output facilities of a display calculator and, if selected by the operator, a printing calculator.

display calculator:
A calculator in which the data output is shown in the form of nonpermanent characters.

display command:
A command that changes the state or that controls the action of a display device.

display console:
A console that includes at least one display surface and may also include one or more input units.

display device:
An output unit that gives a visual representation of data. Usually, the data are displayed temporarily; however, arrangements may be made for producing a hard copy of this representation.

display element:
A basic graphic element that can be used to construct a display image. For example, a dot, a line segment. Synonymous with graphic primitive, output primitive.

display group:
Synonym for display segment.

display image:
A collection of display elements that are represented together at one time on a display surface. Synonymous with image (in computer graphics).

display instruction:
Deprecated synonym for display command.

display line:
The writing line on a display device.

display position:
In computer graphics, any position in a display space that can be occupied by a pixel.

display recall control:
On a battery-powered calculator, a control for recalling a display that has been blanked out by battery-saving circuitry.

display segment:
In computer graphics, a collection of display elements that can be manipulated as a unit. A display segment may consist of several display elements such as dots, arcs, or line segments. Synonymous with display group.

display space:
That portion of a device space corresponding to the area available for displaying images. (Figure 63 - Window/viewport transformation).

display surface:
In a display device, that medium on which display images may appear. For example, the screen of a cathode ray tube, the paper in a plotter.

display window:
Synonym for window.

distortion:
An undesired change in the features of an image or waveform.

distributed database:
A database that is physically decentralized and handled by a database management system in a way that provides a logically centralized view of the database to the user.

distributed data processing (DDP):
Data processing in which the performance of operations is dispersed among the nodes in a computer network. DDP needs collective cooperation that is achieved by data communication among the nodes.

distributed system:
A system that performs distributed data processing.

distributed transaction processing:
A type of distributed data processing in which transactions entered by users are disbursed among several computers for processing.

distribution list (DL):
(1) A list of intended recipients defined and named by, or for the use of, the originator. (2) In electronic mail, an abstraction that represents a pre-specified group of users and other distribution lists and that is a potential destination for the information objects a message handling system conveys. Membership can contain O/R names identifying either users or other distribution lists.

dithering:
A technique for varying raster color or intensity by assigning values from a restricted range available to pixels in patterns; for example, simulating a gray scale by using a group of pixels each capable of displaying only black and white. Dithering is used to create a wide variety of patterns for use as backgrounds, fills and shadings, as well as for creating halftones, and for correcting aliasing. (Figure 22 - Dithering).

DL:
distribution list.

DLE:
The data link escape character.

DLL:
dynamic-link library.

DMA:
direct memory access.

DMD:
directory management domain.

DMF:
data modeling facility.

DML:
data manipulation language.

DNC:
direct numerical control.

DNS:
domain name system, domain name server, domain name service.

docking station:
Hardware that accepts a portable computer so that it can be used as a desktop computer. Synonymous with expansion unit.

document:
(1) Data in a form that generally has persistence and that can be read by man or machine. (2) In text processing, a named, structured unit of text and possibly images that can be stored, edited, retrieved, and exchanged among systems or users as a separate unit.

document architecture:
A complete set of interrelated rules defining the possible structures of documents taken into consideration in a specific text processing environment.

documentation:
(1) One or more of the aids provided for the understanding of the structure and intended uses of an information system or its components, such as flowcharts, textual material, and user manuals. (2) A collection of documents on a given subject.

document body:
The contents of a document, including text, internal graphics, and layout information, but excluding the document profile.

document delivery:
The transfer of a document into the recipient's environment.

document formatter:
A program that allows a user to lay out and obtain a printable copy of a document. A document formatter may perform other functions such as numbering pages or paragraphs.

document interchange format:
The rules for representing documents for the purpose of interchange among users of an office automation system.

document mark:
In micrographics, an optical mark within the recording area and outside the image on a roll of microfilm that may be used to count automatically images or film frames.

document merge:
A function of a text processor that enables a user to create a customized document from previously stored documents or parts of documents. For example, the merging of a form letter with the name and address of recipients recorded in a list.

document profile:
A set of attributes that specifies the characteristics of an entire document, such as its type and format.

document reader:
A character reader whose input data are the text from hard copy of documents.

document reference edge:
In character recognition, a specified edge with respect to which the alignment of characters of the document is defined.

domain:
(1) A specific field of knowledge or expertise. (2) The set of permissible data values from which actual values are taken for a particular attribute or specific data element. Synonymous with attribute domain. (3) In a relational database, all of the permissible tuples for a given relation. (4) In distributed data processing, that part of a computer network in which the resources or addressing are under common control. The domain scheme may be geographical or organizational. (5) In computer security, all of the objects that a subject can access.

domain knowledge:
Knowledge accumulated in a particular domain.

domain model:
A model of a specific field of knowledge or expertise.

domain name:
The identifier for a domain. In the Internet, the fully qualified domain name is composed of multiple parts, hierarchically arranged with the top-level domain name on the right. Contrast with IP address.

domain name server (DNS):
A server within the Internet that performs translation between fully qualified domain names and IP addresses according to the domain name system.

domain name service (DNS):
A service to map fully qualified domain names to IP addresses.

domain name system (DNS):
The set of databases that provides the correspondence between a fully qualified domain name and the associated IP address. The domain name system contains a kind of naming tree for domains and hosts, identifying each Internet node unambiguously.

domain of definition:
A reference set of elements (real or abstract) from which a selection may be made or to which selected elements may be referenced.

dongle:
A security device connected to a port to permit the use of a particular software package on that computer.

dot address:
Synonym for IP address.

dot matrix character generator:
A character generator that generates display images of characters composed of dots located on a parallelogram.

dot matrix printer:
A printer that prints characters or images represented by dots. Synonymous with matrix printer.

dot pattern:
The arrangement and size of dots in an image.

dot pitch:
A measure of spatial resolution on a display, expressed as the distance between phosphor dots of the same color.

double-density disk (DDD):
A floppy disk with the form of a single-density disk but operating at double the original physical recording density. Synonymous with DD disk.

double-ended list:
A list that is constructed and maintained so that it allows insertions and retrieval at either end. Synonymous with double-ended queue. (Figure 23 - Stack, queue, and double-ended list).

double-ended queue:
Deprecated synonym for double-ended list.

double-length register:
Two registers that function as a single register. A double-length register may be used:
  1. in multiplication, for storing the product;
  2. in division, for storing the partial quotient and the remainder;
  3. in character manipulation, for shifting and for accessing character strings.
Synonymous with double register.

double precision:
Characterized by the use of two computer words to represent a number that accomodates the required precision.

double-pulse recording:
Phase modulation recording with unmagnetized regions on each side of the magnetized regions. (Figure 24 - Double-pulse recording).

double-rail logic:
Self-timing asynchronous circuits in which each logical variable is represented by two electrical lines which together can take on three meaningful states: zero, one, and undecided.

double register:
Synonym for double-length register.

double sided/double density (DSDD):
A double-density disk where both sides are used for the recording of data.

doublet:
A byte composed of two bits. Synonymous with 2-bit byte.

double word:
A sequence of contiguous bits or characters that comprise two computer words and that may be addressed as a unit.

DOW disk:
Synonym for direct overwrite disk.

do while statement:
An iteration statement where the iteration control is incorporated in a while-construct.

DOW MO disk:
Synonym for direct overwrite magneto-optical disk.

downlink:
(1) In a local area network, pertaining to data transmission from the headend to a data station. (2) In satellite systems and airborne platforms, that portion of a communication link used for transmission of signals from a satellite or airborne platform to a surface terminal.

download:
To transfer programs or data from another computer. Originally the concept was to transfer data from a large computer to a smaller one.

down time:
The time during which a functional unit is not capable of performing a required function, or is not accessible to the user, or the required external resources are not provided. Contrast with outage.

draft copy:
A preliminary version of a document prepared for review, approval, or editing.

draft mode:
A print option that sacrifices print quality for printing speed.

draft quality:
Print quality of text that is not suitable for business correspondence, but good enough for most internal documents, and that is used to obtain higher printing speed rather than near-letter quality.

dragging:
Relocating display elements on a screen with a pointing device. Dragging is typically done by pressing and holding a pushbutton while moving the pointer on the screen.

DRAM:
dynamic RAM.

drift:
The unwanted change of the value of an output signal of a device over a specified period of time when the values of all input signals of the device are kept constant.

drop cable:
The cable that connects a data station to a trunk coupling unit. (Figure 3 - Interconnection of data stations on a trunk cable).

drop-in:
An error due to the presense of a bit where none was intended.

drop-out:
An error due to the absence of a bit where one was intended, such as failure to detect a bit in a medium or a failure in its recording.

drum plotter:
A plotter that draws a display image on a display surface mounted on a rotating drum.

drum printer:
An impact printer in which a full character set, placed on a rotating drum, is made available for each printing position.

drum scanner:
A scanner that rotates the medium being scanned, such as a sheet of paper, around a stationary scan head.

DSA:
directory system agent.

DSDD:
double sided/double density.

DSE:
data switching exchange.

DSP:
digital signal processor.

DSR:
data signaling rate.

DSS:
decision support system.

DTE:
data terminal equipment.

DTW:
dynamic time warping.

DUA:
directory user agent.

dual-cable broadband LAN:
A broadband LAN that uses separate cables for the forward LAN channel and the backward LAN channel.

dual-homed host:
A host computer that participates in two separate networks. A dual-homed host can provide security functions as a firewall.

dual operation:
In a Boolean operation, another Boolean operation whose result, when it is performed on operands that are the negation of the operands of the first Boolean operation, is the negation of the result of the first Boolean operation; for example, disjunction is the dual operation of conjunction.

dumb terminal:
A user terminal that has no independent data processing capability beyond display, communication, and possibly data entry. Synonymous with nonprogrammable terminal.

dummy:
Pertaining to the characteristic of having the appearance of a specified thing but not having the capacity to function as such; for example, a dummy argument (formal parameter), or a dummy statement.

dummy argument:
Synonym for formal parameter.

dummy instruction:
An item of data in the form of an instruction that is inserted into a sequence of instructions, but that is not intended to be executed.

dump:
(1) To record or display, in a format that facilitates analysis, the contents of all or part of a storage device at a particular instant. Dumps include
  1. internal storage, such as the contents of memory and general-purpose registers and
  2. external storage, such as detailed structures of data on disks or magnetic tapes.
Dumping is usually for debugging. (2) The process of dumping. (3) Data that have been dumped. Synonymous with datadump.

duodecimal:
(1) Characterized by a selection, choice, or condition that has twelve possible different values or states. (2) Of a fixed-radix notation, having a radix of twelve.

duplex transmission:
Data transmission in both directions at the same time. Synonymous with full-duplex transmission.

duplicate:
(1) To make an identical copy of an existing document. (2) To copy from a source data medium to a destination data medium that has the same physical form. For example, to reproduce the contents of one magnetic tape onto another magnetic tape.

duplication check:
A check based on the consistency of the results of two independent performances of the same tasks.

durability:
The ability of a functional unit to perform a required function under given conditions for a given time interval.

DVD (digital versatile disk, digital video disk):
An optical disk with improved capacity, bandwidth, and versatility over the CD. The improved capacity is achieved through closer pit engraving and multilayer technology.

dyadic operation:
An operation on two and only two operands.

dyadic operator:
An operator that represents an operation on two and only two operands.

dye-sublimation printer:
A printer that produces an image using smoothly blended levels of continuous ink for gradations of gray or color. Synonymous with continuous-tone printer.

dynamic:
In programming, pertaining to a data attribute whose values can only be established during the execution of part or all of a program. For example, the length of a variable-length data object is dynamic.

dynamically programmable connection:
In artificial neural networks, a neural connection whose connection weight may be modified dynamically.

dynamic binding:
Binding performed during the execution of a program.

dynamic breakpoint:
A breakpoint for which the specific events or conditions that initiate it may change during the execution of its own or another program.

dynamic buffering:
Allocation of buffer storage as the need arises. Contrast with static buffering.

dynamic image:
Synonym for foreground image.

dynamic-link library (DLL):
An application programming interface, the subprograms of which applications may access through calls to the operating system.

dynamic RAM (DRAM):
A direct access RAM that is a volatile storage and whose content has to be periodically refreshed. A binary state is represented by the presence or absence of electric charge in each storage cell.

dynamic relocation:
The movement of a program to new absolute addresses during a run.

dynamic resource allocation:
An allocation of resources assigned for the execution of programs as determined by criteria applied at the moment of need.

dynamic scope:
The scope created by the activation of portions or all of the modules that contain declarations used by another module that lacks these declarations during the execution of the latter module.

dynamic storage:
(1) Storage that requires periodic refreshment. Contrast with static storage (2) Memory that can be used for dynamic storage allocation.

dynamic storage allocation:
Allocation of storage space to data objects only for the duration of the execution of their scope.

dynamic time warping (DTW):
A procedure using a dynamic programming algorithm that nonlinearly aligns the time scales of stored speech templates and test speech samples to be recognized. The nonlinear alignment is better than the linear alignment and provides a more realistic measure of dissimilarity between the patterns.

dynamic tool display:
A computer-aided design and manufacturing feature whose display represents one or more numerically controlled tools moved along its tool path and its movements displayed on the monitor to simulate and verify a manufacturing process.

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