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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facsimile:
fax.

facsimile machine:
Synonym for fax machine.

fact:
In artificial intelligence, a statement whose validity is accepted with a high certainty factor.

factorial:
The product of the natural numbers 1, 2, 3, . . . up to and including a given integer.

factorial function:
The function that is used to compute factorials.

failsafe:
(1) Pertaining to a functional unit which, in the presence of a fault, assumes a prescribed safe state. Examples of safe states include the shutting down of a functional unit rather than producing erroneous results and a state which limits operations to minimize potential harm. (2) In computer security, pertaining to avoidance of compromise in the event of a failure.

failsafe operation:
The operation of a computer system such that in case of failure of a component, the probabilities of loss of equipment, damage to equipment, and harm to personnel are reduced.

failsoft:
Pertaining to a functional unit continuing to function in a degraded mode despite faults or out-of-limits operations. Fault tolerance is one technique for achieving failsoft operations.

failure:
The termination of the ability of a functional unit to perform a required function.

failure access:
An unauthorized, and usually inadvertent, access to data in a data processing system, resulting from a failure of hardware or software.

failure rate:
The number of failures of a functional unit in a given time interval, divided by the duration of this interval, under stated conditions.

fake sector:
A sector consisting of a header but no data, used in large numbers on a floppy disk to cause an unauthorized copying program to fail to copy the floppy disk.

family-of-parts programming:
A method of creating new parts on a computer-aided design and manufacturing system by making slight changes in the design of existing parts, or by combining parts, subassemblies or structures designed earlier.

fanfold paper:
Continuous forms previously folded as a fan and usually fed by means of feed holes on each side. Synonymous with z-fold paper, zig-zag fold paper.

fan-in:
The number of modules controlling a particular module. A high fan-in value suggests that coupling is high, because it is a measure of module dependencies.

fan-out:
The number of modules controlled by a module. A high fan-out value suggests that the complexity of the calling module may be high because of the complexity of the logic required to control and coordinate the subordinate components.

FAQ:
frequently asked questions.

fast select:
An option of a virtual call facility that allows the inclusion of user data in call set-up and call-clearing packets.

fatal error:
An error that results in the complete inability of a functional unit to perform its required function.

fault:
An abnormal condition that may cause a reduction in, or loss of, the capability of a functional unit to perform a required function.

fault seeding:
Synonym for error seeding.

fault tolerance:
The ability of a functional unit to continue to perform a required function in the presence of faults.

fault trace:
A record of the internal operation of a functional unit, obtained by a monitor that reflects a sequence of states immediately preceding the detection of an error.

fax (facsimile):
(1) The product of transmission of an image of a page or pages and the recreation of that image at a receiving station. Synonymous with telecopy. (2) To create a facsimile. Synonymous with telecopy, telefax.

fax adapter:
Synonym for fax board.

fax board:
An integrated circuit board in a workstation used to transmit or receive fax images over a telephone system. Synonymous with fax adapter.

fax machine:
A functional unit that converts images to signals for transmission over a telecommunication system or converts received signals back to hard copy images. Synonymous with facsimile machine.

fax modem:
A functional unit which combines the functions of a fax machine and the functions of a modem.

FC:
font change character.

FCS:
frame check sequence.

FDDI:
fiber distributed data interface.

FDM:
frequency division multiplexing.

FDMA:
frequency division multiple access.

feasibility study:
A study to identify and analyze a problem and its potential solutions to determine their viability, costs, and benefits.

feature:
In computer graphics, any characteristic descriptive of an image or a region in an image.

feature-based speech recognition:
Speech recognition achieved by template matching of such distinctive features as pitch, formant frequencies, envelope contours, or noise levels.

feature extraction:
In computer graphics, the process of measurement or observation to derive values of features to be used in image analysis.

feature space:
In computer graphics, a set of all possible feature vectors that can be used to represent features of an image.

feature vector:
In computer graphics, an ordered set of features that may be used to describe areas or objects within an image.

FED:
field emission display.

feedback loop:
The components and processes involved in correcting or controlling a system by using part of the output as input.

feedforward network:
In artificial neural networks, a multilayered network with no feedback paths nor any paths between artificial neurons within a given layer; for example, multilayered perceptron. Synonymous with forward-propagation network.

feedforward propagation:
In a multilayered network, the propagation of connection weight adjustment, layer by layer, from the input layer toward the output of the network. Not to be confused with feedforward network. Synonymous with forward propagation.

feed hole:
A hole punched in a data medium to enable it to be positioned. Synonymous with sprocket hole.

feed pitch:
The distance between corresponding points of adjacent feed holes along the feed track.

feed track:
A track in a data medium that contains feed holes. Synonymous with sprocket track.

FEP:
front-end processor.

fetch:
To locate and load a quantity of data from storage.

FF:
The form feed character.

fiber distributed data interface (FDDI):
A standardized technology for the use of fiber-optics in high-speed local area networks.

Fibonacci search:
A dichotomizing search in which the number of data elements in the set is equal to a Fibonacci number or is assumed to be equal to the next higher Fibonacci number and then at each step in the search the set of elements is partitioned in accordance with the Fibonacci series. The series 0, 1, 1, 2, 3, 5, 8, . . ., in which each element is the sum of the two preceding terms, is a Fibonacci series. The Fibonacci search has an advantage over binary search in slightly reducing the average movement of a sequentially accessed data medium, such as a magnetic tape.

field:
In organization of data, a specified area used for a particular class of data elements on a data medium or in a storage device; for example, a group of character positions used to enter or display wage rates on a screen.

field emission display (FED):
A flat-panal display technology using a grid of tiny cathodes for image generation.

field-of-view (FOV):
The solid angle viewed from an observer position and which selects in the scene the content of the image.

field-programmable gate array (FPGA):
A field-programmable logic array with limited capabilities but simpler to program. Field-programmable gate arrays perform low-level switching functions.

field-programmable logic array (FPLA):
A programmable logic array that can be customized by the user.

field separator character (FS):
The information separator intended to identify logical boundaries between fields, files, and other elements of a data structure.

field type:
A data type the instances of which are elementary within a certain conceptual context and that, within this context, represent information of elementary nature. In some contexts, a field type may be a scalar type or a composite type; for example, in a given context, a data type "Date" may be elementary but in other contexts it may consist of field types "Year", "Month", and "Day".

FIFO:
first-in-first-out.

figurative constant:
A data name that is reserved for a specified constant in a specified programming language.

file:
(1) A named set of records treated as a unit. (2) To store records or a document in a file by electronic, optical, or photographic means or as hard copy. (3) In the CODASYL model, a synonym for area.

file layout:
The arrangement and structure of data or words in a file, including the order and size of the components of the file.

file maintenance:
The activity of updating or reorganizing a file.

file organization:
(1) The physical order of records in a file, as determined by the access method used to store and retrieve them.

file protection:
The implementation of appropriate administrative, technical, or physical means to guard against the unauthorized access to, modification of, or deletion of a file.

file server:
A server that manages files and is organized to facilitate access to these files and/or storage of new files.

file transfer:
In networking, the process of copying a file's content over a computer network.

file transfer, access, and management (FTAM):
An application service element that enables user application processes to move files between end open systems and to manage and access a remote set of files, which may be distributed.

file transfer protocol:
FTP.

file updating:
The activity of adding, deleting, or changing data in a file.

filing:
The storing of a record or of a document by electronic, optical, or photographic means or as a hard copy.

fill:
(1) In a token-ring network, a specified bit pattern that a transmitting data station sends before or after frames, tokens, or abort sequences to avoid what would otherwise be interpreted as an inactive or indeterminate transmitter state. (2) In computer graphics, to propagate a repeated arrangement of display elements throughout a closed area or object.

filler:
One or more characters that are used to bring the representation of a data item up to a specified size.

filler character:
A specific character or bit combination used to fill the remainder of a field after justification.

fill pattern:
A repeated arrangement of display elements with which a closed area is filled.

filter:
A device or program that separates data or signals in accordance with specified criteria.

filtering:
Synonym for pattern matching (in artificial intelligence).

find:
Synonym for search.

find and replace:
Synonym for search and replace.

finite element analysis:
In computer-integrated manufacturing, the analysis of the structural properties of a mechanical part, or more generally a physical construction, based on simulative decomposition into discrete elements.

finite element modeling:
In computer-integrated manufacturing, the creation on a data processing system of a mathematical model representing a mechanical part or physical construction under design for finite element analysis.

fire a rule:
In artificial intelligence, to initiate the action specified by a rule when the condition stated by the rule is satisfied.

firewall:
A functional unit that mediates all traffic between two computer networks and protects one of them or some part thereof against unauthorized access. The protected network is in general a private, internal network. A firewall may permit messages or files to be transferred to a high-security workstation within the internal network, without permitting such transfer in the opposite direction.

firmware:
An ordered set of instructions and associated data stored in a manner that they are considered part of the hardware configuration as distinct from the software that is dynamically loaded as needed; for example, microprograms stored in read-only memory. Firmware may be implemented in hardware logic or stored in read-only memory; it may be addressed as part of the memory address space or be entirely separate. (Figure 2 - Hierarchy of language).

first-generation language (1GL):
A programming language closely resembling assembly language and very dependent on the machine language of a computer.

first-in-first-out (FIFO):
A queuing technique in which the next item to be retrieved is the item that has been in the queue the longest time. (Figure 23 - Stack, queue, and double-ended list).

first-line find:
Synonym for form feed.

fitness-for-use test:
Synonym for usability test.

fixed-count iteration:
An iteration scheme that terminates execution of a loop after a specific number of iterations rather than until a specific condition occurs.

fixed-cycle operation:
An operation that is completed in a specified number of regularly timed execution cycles.

fixed decimal mode:
A mode in which the number of decimal places to be shown in the result of a calculation is preselected.

fixed disk:
Synonym for hard disk.

fixed disk drive:
A disk drive in which the data medium is permanently attached within the device.

fixed-function generator:
A function generator in which the function it generates is set by construction and cannot be altered by the user.

fixed-pitch spacing:
Synonym for monospacing.

fixed-point part:
In a floating-point representation, the numeral that is multiplied by the exponentiated implicit floating-point base to determine the real number represented; for example, a floating-point representation of the number 0.0001234 is 0.1234 E-3, where: 0.1234 is the fixed-point part and E-3 is the exponent.

fixed-point representation system:
A radix notation in which the radix point is implicitly fixed in the series of digit places by some convention.

fixed-point type:
A numeric data type whose values are expressed in a fixed-point representation system. Synonymous with implied decimal type.

fixed-radix notation:
A radix notation in which all the digit places, except perhaps the one with the highest weight, have the same radix. The weights of successive digit places are successive integral powers of a single radix, each multiplied by the same factor. Negative integral powers of the radix are used in the representation of fractions. A fixed-radix notation is a special case of a mixed-radix notation.

fixed spacing:
Synonym for monospacing.

flag:
A variable indicating the status of a certain condition.

flag register:
Synonym for status register.

flame:
In networking, a strong opinion or criticism of something, usually as a frank, inflammatory statement in a forum or in an electronic mail system. Synonymous with flaming.

flaming:
Synonym for flame.

flash card:
(1) In micrographics, a target with distinctive markings that is photographed to facilitate the indexing of microfilm. (2) Deprecated synonym for flash memory card.

flash memory:
Nonvolitle memory that can be erased and reprogrammed in blocks instead of one byte at a time.

flash memory card:
A memory module in card format incorporating flash memory logic.

flatbed plotter:
A plotter that draws a display image on a flat display surface.

flatbed scanner:
A scanner characterized by a flat surface on which the item to be scanned is placed.

flat file:
(1) A one-dimensional array of records; for example, a list or table. (2) A collection of records that contain no data aggregates, and no nested repeating groups of data items.

flatness-of-field:
The degree to which a flat object appears as a flat image.

flat-panel display:
A display device whose physical depth (front to back) is relatively shallow; for example a plasma panel or a liquid-crystal display.

flaw:
In computer security, a mistake that allows protection mechanisms to be bypassed or disabled. Synonymous with loophole.

flexible disk:
Synonym for floppy disk.

flexible diskette:
Synonym for floppy disk.

flexible manufacturing system (FMS):
A system composed of numerically controlled manufacturing units and transport mechanisms that allows for easy adjustment to changes in manufacturing tasks.

flicker:
In computer graphics, an undesirable rhythmic variation in one of the characteristics of a display image, such as intensity or color.

flip-flop:
A circuit that alternates between two possible stable states whenever a suitable input pulse is applied. Synonymous with bistable trigger circuit, bistable circuit.

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