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.

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.

Source Documents

1. The New IEEE Standard Dictionary of Electrical and Electronics Terms, IEEE Std. 100-1992.
2. IEEE Standards Collection, Software Engineering, 1994 Edition, published by the Institute of Electrical and Electronic Engineers Inc.
3. National Bureau of Standards [NBS] Special Publication 500-75 Validation, Verification, and Testing of Computer Software, 1981.
4. Federal Information Processing Standards [FIPS] Publication 101, Guideline For Lifecycle Validation, Verification, and Testing of Computer Software, 1983.
5. Federal Information Processing Standards [FIPS] Publication 105, Guideline for Software Documentation Management, 1984.
6. American National Standard for Information Systems, Dictionary for Information Systems, American National Standards Institute, 1991.
7. FDA Technical Report, Software Development Activities, July 1987.
8. FDA Guide to Inspection of Computerized Systems in Drug Processing, 1983.
9. FDA Guideline on General Principles of Process Validation, May 1987.
10. Reviewer Guidance for Computer Controlled Medical Devices Undergoing 510(k) Review, Office of Device Evaluation, CDRH, FDA, August 1991.
11. HHS Publication FDA 90-4236, Preproduction Quality Assurance Planning.
12. MIL-STD-882C, Military Standard System Safety Program Requirements, 19JAN1993.
13. International Electrotechnical Commission, International Standard 1025, Fault Tree Analysis.
14. International Electrotechnical Commission, International Standard 812, Analysis Techniques for System Reliability - Procedure for Failure Mode and Effects Analysis [FMEA].
15. FDA recommendations, Application of the Medical Device GMP to Computerized Devices and Manufacturing Processes, May 1992.
16. Pressman, R., Software Engineering, A Practitioner's Approach, Third Edition, McGraw-Hill, Inc., 1992.
17. Myers, G., The Art of Software Testing, Wiley Interscience, 1979.
18. Beizer, B., Software Testing Techniques, Second Edition, Van Nostrand Reinhold, 1990.
19. Additional general references used in developing some definitions are:
20. Bohl, M., Information Processing, Fourth Edition, Science Research Associates, Inc., 1984.
21. Freedman, A., The Computer Glossary, Sixth Edition, American Management Association, 1993.
22. McGraw-Hill Electronics Dictionary, Fifth Edition, 1994, McGraw-Hill Inc.
23. McGraw-Hill Dictionary of Scientific & Technical Terms, Fifth Edition, 1994, McGraw-Hill Inc..
24. Webster's New Universal Unabridged Dictionary, Deluxe Second Edition, 1979.

The bulk of this information was obtained from FDA.gov.