Glossary of Computer Software Development Terminology
The terms are defined, as much as possible, using available standards. The source of such definitions appears immediately following the term or phrase in parenthesis, e.g. (NIST).
The source documents are listed at the bottom of this page.
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FDD. floppy disk drive.
FIPS. Federal Information Processing Standards.
FMEA. Failure Modes and Effects Analysis.
FMECA. Failure Modes and Effects Criticality Analysis.
FTA. Fault Tree Analysis.
FTP. file transfer protocol.
Fagan inspection. See: code inspection.
fail-safe. (IEEE) A system or component that automatically places itself in a safe operational mode in the event of a failure.
failure. (IEEE) The inability of a system or component to perform its required functions within specified performance requirements. See: bug, crash, exception, fault.
failure analysis. Determining the exact nature and location of a program error in order to fix the error, to identify and fix other similar errors, and to initiate corrective action to prevent future occurrences of this type of error. Contrast with debugging.
Failure Modes and Effects Analysis. (IEC) A method of reliability analysis intended to identify failures, at the basic component level, which have significant consequences affecting the system performance in the application considered.
Failure Modes and Effects Criticality Analysis. (IEC) A logical extension of FMEA which analyzes the severity of the consequences of failure.
fault. An incorrect step, process, or data definition in a computer program which causes the program to perform in an unintended or unanticipated manner. See: anomaly, bug, defect, error, exception.
fault seeding. See: error seeding.
Fault Tree Analysis. (IEC) The identification and analysis of conditions and factors which cause or contribute to the occurrence of a defined undesirable event, usually one which significantly affects system performance, economy, safety or other required characteristics.
feasibility study. Analysis of the known or anticipated need for a product, system, or component to assess the degree to which the requirements, designs, or plans can be implemented.
Federal Information Processing Standards. Standards published by U.S. Department of Commerce, National Institute of Standards and Technology, formerly National Bureau of Standards. These standards are intended to be binding only upon federal agencies.
fiber optics. Communications systems that use optical fibers for transmission. See: optical fiber.
field. (1) (ISO) On a data medium or in storage, a specified area used for a particular class of data; e.g., a group of character positions used to enter or display wage rates on a screen. (2) Defined logical data that is part of a record. (3) The elementary unit of a record that may contain a data item, a data aggregate, a pointer, or a link. (4) A discrete location in a database that contains an unique piece of information. A field is a component of a record. A record is a component of a database.
file. (1) (ISO) A set of related records treated as a unit; e.g., in stock control, a file could consists of a set of invoices. (2) The largest unit of storage structure that consists of a named collection of all occurrences in a database of records of a particular record type. Syn: data set.
file maintenance. (ANSI) The activity of keeping a file up to date by adding, changing, or deleting data.
file transfer protocol. (1) Communications protocol that can transmit binary and ASCII data files without loss of data. See: Kermit, Xmodem, Ymodem, Zmodem. (2) TCP/IP protocol that is used to log onto the network, list directories, and copy files. It can also translate between ASCII and EBCDIC. See: TCP/IP.
firmware. (IEEE) The combination of a hardware device; e.g., an IC; and computer instructions and data that reside as read only software on that device. Such software cannot be modified by the computer during processing. See: embedded software.
flag. (IEEE) A variable that is set to a prescribed state, often "true" or "false", based on the results of a process or the occurrence of a specified condition. Syn: indicator.
flat file. A data file that does not physically interconnect with or point to other files. Any relationship between two flat files is logical; e.g., matching account numbers.
floppy disk. See: diskette.
floppy disk drive. See: disk, disk drive.
flowchart or flow diagram. (2) (ISO) A graphical representation in which symbols are used to represent such things as operations, data, flow direction, and equipment, for the definition, analysis, or solution of a problem. (2) (IEEE) A control flow diagram in which suitably annotated geometrical figures are used to represent operations, data, or equipment, and arrows are used to indicate the sequential flow from one to another. Syn: flow diagram. See: block diagram, box diagram, bubble chart, graph, input-process-output chart, structure chart.
formal qualification review. (IEEE) The test, inspection, or analytical process by which a group of configuration items comprising a system is verified to have met specific contractual performance requirements. Contrast with code review, design review, requirements review, test readiness review.
FORTRAN. An acronym for FORmula TRANslator, the first widely used high-level programming language. Intended primarily for use in solving technical problems in mathematics, engineering, and science.
full duplex. See: duplex transmission.
function. (1) (ISO) A mathematical entity whose value, namely, the value of the dependent variable, depends in a specified manner on the values of one or more independent variables, with not more than one value of the dependent variable corresponding to each permissible combination of values from the respective ranges of the independent variables. (2) A specific purpose of an entity, or its characteristic action. (3) In data communication, a machine action such as carriage return or line feed.
functional analysis. (IEEE) Verifies that each safety-critical software requirement is covered and that an appropriate criticality level is assigned to each software element.
functional configuration audit. (IEEE) An audit conducted to verify that the development of a configuration item has been completed satisfactorily, that the item has achieved the performance and functional characteristics specified in the functional or allocated configuration identification, and that its operational and support documents are complete and satisfactory. See: physical configuration audit.
functional decomposition. See: modular decomposition.
functional design. (IEEE) (1) The process of defining the working relationships among the components of a system. See: architectural design. (2) The result of the process in (1).
functional requirement. (IEEE) A requirement that specifies a function that a system or system component must be able to perform. |
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Source Documents
The bulk of this information was obtained from FDA.gov. |
BIOS. basic input/output system.
bps. bits per second.
band. Range of frequencies used for transmitting a signal. A band can be identified by the difference between its lower and upper limits, i.e. bandwidth, as well as by its actual lower and upper limits; e.g., a 10 MHz band in the 100 to 110 MHz range.
bandwidth. The transmission capacity of a computer channel, communications line or bus. It is expressed in cycles per second [Hz], and also is often stated in bits or bytes per second. See: band.
bar code. (ISO) A code representing characters by sets of parallel bars of varying thickness and separation that are read optically by transverse scanning.
baseline. (NIST) A specification or product that has been formally reviewed and agreed upon, that serves as the basis for further development, and that can be changed only through formal change control procedures.
BASIC. An acronym for Beginners All-purpose Symbolic Instruction Code, a high-level programming language intended to facilitate learning to program in an interactive environment.
basic input/output system. Firmware that activates peripheral devices in a PC. Includes routines for the keyboard, screen, disk, parallel port and serial port, and for internal services such as time and date. It accepts requests from the device drivers in the operating system as well from application programs. It also contains autostart functions that test the system on startup and prepare the computer for operation. It loads the operating system and passes control to it.
batch. (IEEE) Pertaining to a system or mode of operation in which inputs are collected and processed all at one time, rather than being processed as they arrive, and a job, once started, proceeds to completion without additional input or user interaction. Contrast with conversational, interactive, on-line, real time.
batch processing. Execution of programs serially with no interactive processing. Contrast with real time processing.
baud. The signalling rate of a line. It's the switching speed, or number of transitions [voltage or frequency change] made per second. At low speeds bauds are equal to bits per seconds; e.g., 300 baud is equal to 300 bps. However, one baud can be made to represent more than one bit per second.
benchmark. A standard against which measurements or comparisons can be made.
bias. A measure of how closely the mean value in a series of replicate measurements approaches the true value. See: accuracy, precision, calibration.
binary. The base two number system. Permissible digits are "0" and "1".
bit. A contraction of the term binary digit. The bit is the basic unit of digital data. It may be in one of two states, logic 1 or logic 0. It may be thought of as a switch which is either on or off. Bits are usually combined into computer words of various sizes, such as the byte.
bits per second. A measure of the speed of data transfer in a communications system.
black-box testing. See: testing, functional.
block. (ISO) (1) A string of records, words, or characters that for technical or logical purposes are treated as a unity. (2) A collection of contiguous records that are recorded as a unit, and the units are separated by interblock gaps. (3) A group of bits or digits that are transmitted as a unit and that may be encoded for error-control purposes. (4) In programming languages, a subdivision of a program that serves to group related statements, delimit routines, specify storage allocation, delineate the applicability of labels, or segment parts of the program for other purposes. In FORTRAN, a block may be a sequence of statements; in COBOL, it may be a physical record.