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- bit:
- Either of the digits 0 or 1 when used in the binary system. Synonymous with binary digit.
- bit configuration:
- The order for encoding the bits of data that define a character or other value.
- bit density:
- A measure of the number of bits recorded per unit of length or area. Synonymous with recording density.
- bit error rate:
- Deprecated synonym for bit error ratio.
- bit error ratio (BER):
- The number of erroneous bits divided by the total number of bits transmitted, received, or processed over some stipulated period of time.
- bitmap:
- A two-dimensional array of bits indicating the presence or absence of an attribute. For more general attribute representations, the preferred term is pixel map. Synonymous with bitplane.
- bit-oriented protocol:
- A data link protocol in which data-link control functions are specified in particular positions of the frame, allowing user data to be transferred as a transparent sequence of bits; for example, the high-level data link control protocol.
- bitplane:
- Synonym for bitmap.
- bit position:
- The position of a binary digit in a byte, a word, or in another appropriate unit.
- bit rate:
- The speed at which bits are transferred. The bit rate is usually expressed in bits per second, kilobits per second, megabits per second, etc.
- bit slice processor:
- A processor constructed of an array of identical units, each of which operates simultaneously upon one or more adjacent bits.
- bit string:
- A string consisting solely of bits.
- blackboard model:
- A problem-solving paradigm analogous to the use of a blackboard in a classroom, where a shared working memory (the "blackboard") is used to communicate intermediate results with the aid of a scheduler, that determines which knowledge source has access at any given time.
- black box:
- A unit of hardware or software whose function is documented but whose internal structure is unknown.
- blank:
- A character that represents an empty position in a graphic character string. A blank is conceptually different from a space character but may not be differentiated in a particular character set. For example, some character sets include a blank as a "nonbreaking space" that may be used between two graphic characters without being treated as a delimiter. Synonymous with blank character.
- blanking:
- The suppression of one or more regions in a display.
- blank medium:
- A data medium in or on which neither marks of reference nor user data have been recorded.
- blind-copy recipient:
- A recipient whose identity is not to be disclosed to other recipients of the same message. The abbreviation "bcc" used to designate a blind-copy recipient is derived from "blind carbon copy".
- blinding:
- The desensitizing of an image device due to exposure to intense light.
- blinking:
- An intentional periodic change in the intensity of one or more display elements.
- blob:
- (1) binary large object. (2) In computer graphics, a region in an image in which all pixels have the same color value.
- blob addressing:
- The mechanism used to select a blob, such as sequential addressing, X-Y addressing, and addressing by blob-identification number.
- blob analysis:
- Image analysis using an algorithm that identifies segmented objects according to geometrical properties of blobs, such as the shapes of perimeters.
- blob growing:
- Synonym for region growing.
- block:
- (1) In organization of data, a string of characters, of words, or of records, that is treated as a unit for a given purpose . (2) In text processing, a user-defined segment of text, usually rectangular, on which a text processing operation is to be performed.
- block cancel character:
- A cancel character used to indicate that the preceding portion of the block, back to the most recently occurring block mark, is to be disregarded. Synonymous with block ignore character.
- block check:
- That part of the error control procedure used for determining that a data block is structured according to given rules.
- block copy:
- A function that enables a user to duplicate a block of text and to insert it at another location within the document, or into another document.
- block diagram:
- A diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks.
- blocked:
- Pertaining to the task state of an executable task in which the task is delayed or waiting for an event.
- block ignore character:
- Synonym for block cancel character.
- blocking factor:
- The maximum number of records in a block.
- block length:
- Synonym for block size.
- block move:
- In text processing, a function that enables a user to designate a block of text and to move it to another location in a document or into another document. Block moves may be accomplished by cut and paste or by drag and drop.
- block size:
- The number of bytes, or any other appropriate unit, in a block. Synonymous with block length.
- block statement:
- In programming, any bounded sequence of statements that can be taken as a single syntactic unit and which may have an identifier. A block statement is a basic syntactic component of block-structured languages. For example: in Pascal, a procedure can be considered simply as a specific header followed by a block statement. In some programming languages (e.g., Ada) this concept is given very specific meaning and may include declarations and exception handlers. Implementation of a block statement usually has an impact on the scope and lifetime of data objects declared as part of a block statement. In other programming languages (e.g., C++), "block" is synonymous with compound statement.
- block structure:
- A hierarchy of program blocks.
- block-structured language:
- A programming language that supports the use of block statements; for example, Ada, ALGOL, C, Pascal, PL/I.
- blocks world:
- A small artificial world consisting of blocks, cylinders, and pyramids, used to develop ideas in logic, computer vision, robotics, natural-language interfaces, etc.
- block transfer:
- The process of transferring one or more blocks of data in one operation. A block transfer can be done with or without erasing data from the original location.
- blooming:
- Smearing of regions of the image where the detected brightness is at an excessive level to the receiving element due to electronic contamination from neighboring bright pixels.
- blowback:
- In micrographics, an enlargement.
- blur circle:
- The apparent circle in an image corresponding to a point source of light and caused by an optical system. The quality of the optical system and its focus affect the size of the blur circle; the smaller, the better.
- BNF:
- Backus-Naur form.
- board:
- A functional unit, typically consisting of a panel of insulating material, with electronic components on one or both sides, and connectors.
- body:
- (1) In programming languages, a language construct that comprises the executable part of a statement or module. (2) In some types of electronic mail messages, Web pages, etc., that part of the content that the originator explicitly communicates, but not including heading and certain control data. The body may consist of one or more parts.
- body stub:
- In programming, a form of a body that indicates that the executable part of a module is defined in a subunit.
- body suit:
- A suit for sensory body input and/or output. Synonymous with data suit, full-body suit.
- BOF:
- beginning of file.
- boilerplate:
- Stored text intended for reuse in multiple documents.
- Boltzmann machine:
- In artificial neural networks, a totally connected network having both visible neurons and hidden neurons, cyclically updated according to a probability distribution. During learning, some visible neurons are clamped onto specific states. There is some formal equivalence between statistical thermodynamics and the dynamic behavior of the Boltzmann machine.
- bombing:
- Malicious flooding.
- bookmark:
- (1) In hypermedia, a user-specified marker that facilitates access to a particular hypermedia node. (2) A reference to a network address which facilitates the use of that address, typically as a hyperlink.
- Boolean:
- Pertaining to the processes used in the algebra formulated by the mathematician George Boole in 1847.
- Boolean add:
- Synonym for OR.
- Boolean complementation:
- Deprecated synonym for negation.
- Boolean expression:
- A language construct that defines the computation of a logical value in accordance with the rules of Boolean algebra.
- Boolean function:
- A switching function in which the number of possible values of the function and of each of its independent variables is two.
- Boolean operation:
- Any operation in which each of the operands and the result take one of two values in accordance with the rules of Boolean algebra. (Figure 4 - Table of Boolean operations).
- Boolean operation table:
- An operation table that defines the logic of Boolean operations.
- Boolean operator:
- An operator defined by the rules of Boolean algebra.
- Boolean type:
- Synonym for logical type.
- boot:
- To initialize a computer by reloading the operating system and possibly clearing memory.
- bootstrap:
- (1) A short program that is permanently resident or easily loaded into a computer and whose execution brings a larger program, such as an operating system or its loader, into memory. Synonymous with initial program load (IPL). (2) To execute a bootstrap.
- bootstrap loader:
- A short program used to load a bootstrap.
- border:
- A region surrounding a window, usually having equal thickness on all sides.
- borrow:
- An arithmetically negative carry.
- borrow digit:
- A digit that is generated when a difference in a digit place is arithmetically negative and that is transferred for processing elsewhere. In a positional notation, a borrow digit is transferred to the digit place with the next higher weight for processing there.
- BOT:
- beginning-of-tape.
- BOT marker:
- Synonym for beginning-of-tape marker.
- bottleneck layer:
- The hidden layer that forces a neural network to develop a compact representation of the input data.
- bottom-up:
- Pertaining to a method or procedure that starts at the lowest level of abstraction and proceeds towards the highest level.
- boundary:
- An abstract line demarking the separation between two regions, typically along an edge. Contrast with edge.
- boundary representation (b-rep):
- Solid modeling by representing a solid object in terms of its interface boundaries: vertices, edges, and faces.
- boundary tracing:
- The process that follows the edges of a blob to determine its complete outline. Synonymous with tracing.
- bounding box:
- In computer graphics, a normally invisible rectangle that encloses a graphic object, and that may appear when this graphic object is selected.
- box diagram:
- A control flow diagram consisting of sequenced and nested boxes that represent sequential steps, repetition, and conditional statements. Synonymous with Chapin chart, Nassi-Shneiderman chart. (Figure 5 - Box diagram).
- BPN:
- back-propagation network.
- branch:
- (1) In a network, a direct interconnection between two nodes. In network topology or in an abstract arrangement, the branches are lines on a scheme. In a computer network, the branches are data links. (2) A direct path joining two nodes of a graph. (3) A set of instructions that are executed between two successive jump instructions. (4) Loosely, a conditional jump. (5) To select a branch as in (3).
- branching point:
- In an interactive medium presentation, a location in a program where the user may choose among two or more paths.
- breach:
- The circumvention or disablement of some element of computer security, with or without detection, which could result in a penetration of the data processing system. (Figure 57 - Levels of security risks).
- breadth-first search:
- A search that proceeds from higher levels to lower levels of a search tree, checking the nodes across all the possible alternatives at one level before going to the next lower level until the goal or a predetermined condition is reached.
- breakout box:
- A small hardware device that can be attached between two devices normally connected by a cable to display and, if necessary, change the activity through individual wires of the cable.
- breakpoint:
- A point in a program, module, or statement where execution may be suspended depending on a specific condition or event. A breakpoint is set to permit manual or automatic monitoring of program performance or results. There may be more than one breakpoint.
- bridge:
- A functional unit that interconnects two computer networks based on a common link level protocol and selects data to be passed based on link addresses. (Figure 6 - Interconnecting networks).
- bridge-router:
- Synonym for brouter.
- brightness:
- An attribute of visual sensation, in accordance with which a source appears to emit more or less light. Brightness is a qualitative concept for human perception and should not to be confused with luminance.
- brightness sliding:
- An image-enhancement operation that involves the addition or subtraction of a luminance constant to all pixels in an image. The result of this addition or subtraction may be clipped at a certain threshold value.
- broadband:
- A frequency band that is used for an application requiring a wide range of frequencies. The broadband can be divided into several narrower bands, each band of which can be used for different purposes or be made available to different users. Synonymous with wideband.
- broadband LAN:
- A local area network consisting of more than one channel, in which data are encoded, multiplexed, and transmitted with modulation of carriers.
- broadcast:
- Transmission of the same data to all destinations.
- broadcast mail:
- Electronic mail that is transmitted to all user terminals in a computer network.
- brouter:
- A functional unit that is able to combine the functions of a bridge and a router. Synonymous with bridge-router.
- browser:
- A functional unit that supports a user in browsing.
- browsing:
- (1) In hypermedia and multimedia, the navigation through hyperdocuments, such as on the World Wide Web. Contrast with
surf. (2) Any method of scanning; for example, scanning directories for executable programs. (3) In text processing, the use of scrolling to accomplish the rapid review of displayed text.
- brute-force attack:
- Synonym for exhaustive attack.
- BS:
- The backspace character.
- B-tree:
- A version of a balanced tree where all paths leading from the root node to a terminal node have the same length. A B-tree has the following properties, where n is the order of the B-tree:
- each node contains at most 2n items;
- each node, except the root node, contains at least n items;
- each node is either a terminal node or it has m+1 subordinate nodes, where m is its number of items.
B-trees are used for fast access to data on external storage. The number of accesses to each item of data is <logn+1(m).
- bubble chart:
- A diagram in which entities are depicted with circles (bubbles) and relationships are represented by links drawn between the circles. (Figure 7 - Bubble chart).
- bubblejet printer:
- A nonimpact printer that forms the characters or unique images by projecting heated particles or droplets of ink onto the output medium.
- bubble memory:
- A magnetic storage that uses nonvolatile bubble-shaped areas in thin film.
- bubble sort:
- An exchange sort in which lower values (or their addresses) float to the top and higher values (or their addresses) sink to the bottom. Synonymous with sifting sort.
- buffer:
- (1) A routine or storage used to compensate for differences in rate of flow of data, or time of occurrence of events, when transferring data from one device to another. (2) An isolating circuit used to prevent a driven circuit from influencing the driving circuit. (3) To allocate and schedule the use of buffers. (4) A special-purpose storage device or a storage area allowing, through temporary storage, the data transfer between two functional units having different transfer characteristics. A buffer is used between nonsynchronized devices, or where one is serial and the other is parallel or between those having different transfer rates.
- buffer storage:
- Storage used as a buffer.
- bug:
- A mistake or malfunction.
- bug seeding:
- Synonym for error seeding.
- built-in:
- Synonym for predefined.
- built-in check:
- Synonym for automatic check.
- bulk eraser:
- A device for eliminating all information from a storage medium, such as a floppy disk or a tape, by generating a strong magnetic field that scrambles the alignment of the ferrous materials in the media that encode stored data.
- bulletin board:
- A computer conference that is devoted to posting and discussing announcements and messages of interest to a specific community of users.
- bulletin board system (BBS):
- A computer system used for supporting a bulletin board. In current practice, in a bulletin board system, only authorized persons may post messages. Traditionally, bulletin board systems are accessible for anonymous readers; no user identification is required to read messages. A bulletin board system also can be used for uploading and downloading files as well as obtaining online data and services.
- bundle:
- In artificial neural networks, a collection of neural connections between slabs.
- burned image:
- An image that is permanent and that remains in a fixed position after the image should no longer exist.
- burn in:
- (1) A process of increasing the reliability of new or refurbished hardware by operating it in a prescribed environment and by performing corrective maintenance, if applicable, for every fault detected, with a view to eliminating as many early faults as possible or discarding faulty but nonrepairable units.
(2) Deprecated synonym for burned image.
- burst:
- (1) In data communications, a sequence of signals counted as one unit in accordance with some specific criterion or measure. (2) To separate continuous-forms paper into discrete sheets.
- burst transmission:
- Data transmission at a specific data signaling rate during controlled intermittent intervals.
- bus:
- An open-loop device designed for transferring data between several devices located between its two end-points, only one device being able to transmit at a given time.
- bus mouse:
- A mouse that attaches to the computer's bus through a special card or parallel port rather than through a serial port. Contrast with serial mouse.
- bus network:
- A network in which there is only one path between any two data stations and in which data transmitted by any station are available to all other stations connected to the same transmission medium.
- bus-quiet signal:
- In a token-bus network, a signal indicating that the transmission medium is inactive.
- bus topology:
- A computer network in which all computers and data communication equipment are connected to a common transmission medium. There is only one path between any two nodes.
- button:
- Synonym for pushbutton.
- byte:
- A string that consists of a number of bits, treated as a unit, and frequently representing a character or a part of a character. The number of bits in a byte is fixed for a given data processing system, and usually is eight.