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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.
RAM. random access memory.
RFI. radiofrequency interference.
RISC. reduced instruction set computer.
ROM. read only memory.
radiofrequency interference. High frequency electromagnetic waves that emanate from electronic devices such as chips and other electronic devices. An electromagnetic disturbance caused by such radiating and transmitting sources as electrostatic discharge [ESD], lightning, radar, radio and TV signals, and motors with brushes can induce unwanted voltages in electronic circuits, damage components and cause malfunctions. See: electromagnetic interference.
random access memory. Chips which can be called read/write memory, since the data stored in them may be read or new data may be written into any memory address on these chips. The term random access means that each memory location [usually 8 bits or 1 byte] may be directly accessed [read from or written to] at random. This contrasts to devices like magnetic tape where each section of the tape must be searched sequentially by the read/write head from its current location until it finds the desired location. ROM memory is also random access memory, but they are read only not read/write memories. Another difference between RAM and ROM is that RAM is volatile, i.e. it must have a constant supply of power or the stored data will be lost.
range check. (ISO) A limit check in which both high and low values are stipulated.
rapid prototyping. A structured software requirements discovery technique which emphasizes generating prototypes early in the development process to permit early feedback and analysis in support of the development process. Contrast with incremental development, spiral model, waterfall model. See: prototyping.
read only memory. A memory chip from which data can only be read by the CPU. The CPU may not store data to this memory. The advantage of ROM over RAM is that ROM does not require power to retain its program. This advantage applies to all types of ROM chips; ROM, PROM, EPROM, and EEPROM.
real time. (IEEE) Pertaining to a system or mode of operation in which computation is performed during the actual time that an external process occurs, in order that the computation results can be used to control, monitor, or respond in a timely manner to the external process. Contrast with batch. See: conversational, interactive, interrupt, on-line.
real time processing. A fast-response [immediate response] on-line system which obtains data from an activity or a physical process, performs computations, and returns a response rapidly enough to affect [control] the outcome of the activity or process; e.g., a process control application. Contrast with batch processing.
record. (1) (ISO) a group of related data elements treated as a unit. [A data element (field) is a component of a record, a record is a component of a file (database)].
record of change. Documentation of changes made to the system. A record of change can be a written document or a database. Normally there are two associated with a computer system, hardware and software. Changes made to the data are recorded in an audit trail.
recursion. (IEEE) (1) The process of defining or generating a process or data structure in terms of itself. (2) A process in which a software module calls itself.
reduced instruction set computer. Computer architecture that reduces the complexity of the chip by using simpler instructions. Reduced instruction set does not necessarily mean fewer instructions, but rather a return to simple instructions requiring only one or a very few instruction cycles to execute, and therefore are more effectively utilized with innovative architectural and compiler changes. Systems using RISC technology are able to achieve processing speeds of more than five million instructions per second.
region. A clearly described area within the computer's storage that is logically and/or physically distinct from other regions. Regions are used to separate testing from production [normal use]. Syn: partition.
register. A small, high speed memory circuit within a microprocessor that holds addresses and values of internal operations; e.g., registers keep track of the address of the instruction being executed and the data being processed. Each microprocessor has a specific number of registers depending upon its design.
regression analysis and testing. (IEEE) A software V&V task to determine the extent of V&V analysis and testing that must be repeated when changes are made to any previously examined software products. See: testing, regression.
relational database. Database organization method that links files together as required. Relationships between files are created by comparing data such as account numbers and names. A relational system can take any two or more files and generate a new file from the records that meet the matching criteria. Routine queries often involve more than one data file; e.g., a customer file and an order file can be linked in order to ask a question that relates to information in both files, such as the names of the customers that purchased a particular product. Contrast with network database, flat file.
release. (IEEE) The formal notification and distribution of an approved version. See: version.
reliability. (IEEE) The ability of a system or component to perform its required functions under stated conditions for a specified period of time. See: software reliability.
reliability assessment. (ANSI/IEEE) The process of determining the achieved level of reliability for an existing system or system component.
requirement. (IEEE) (1) A condition or capability needed by a user to solve a problem or achieve an objective. (2) A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed documents. (3) A documented representation of a condition or capability as in (1) or (2). See: design requirement, functional requirement, implementation requirement, interface requirement, performance requirement, physical requirement.
requirements analysis. (IEEE) (1) The process of studying user needs to arrive at a definition of a system, hardware, or software requirements. (2) The process of studying and refining system, hardware, or software requirements. See: prototyping, software engineering.
requirements phase. (IEEE) The period of time in the software life cycle during which the requirements, such as functional and performance capabilities for a software product, are defined and documented.
requirements review. (IEEE) A process or meeting during which the requirements for a system, hardware item, or software item are presented to project personnel, managers, users, customers, or other interested parties for comment or approval. Types include system requirements review, software requirements review. Contrast with code review, design review, formal qualification review, test readiness review.
retention period. (ISO) The length of time specified for data on a data medium to be preserved.
retrospective trace. (IEEE) A trace produced from historical data recorded during the execution of a computer program. Note: this differs from an ordinary trace, which is produced cumulatively during program execution. See: execution trace, subroutine trace, symbolic trace, variable trace.
revalidation. Relative to software changes, revalidation means validating the change itself, assessing the nature of the change to determine potential ripple effects, and performing the necessary regression testing.
review. (IEEE) A process or meeting during which a work product or set of work products, is presented to project personnel, managers, users, customers, or other interested parties for comment or approval. Types include code review, design review, formal qualification review, requirements review, test readiness review. Contrast with audit, inspection. See: static analysis.
revision number. See: version number.
risk. (IEEE) A measure of the probability and severity of undesired effects. Often taken as the simple product of probability and consequence.
risk assessment. (DOD) A comprehensive evaluation of the risk and its associated impact.
robustness. The degree to which a software system or component can function correctly in the presence of invalid inputs or stressful environmental conditions. See: software reliability.
routine. (IEEE) A subprogram that is called by other programs and subprograms. Note: This term is defined differently in various programming languages. See: module.
RS-232-C. An Electronic Industries Association (EIA) standard for connecting electronic equipment. Data is transmitted and received in serial format.
The bulk of this information was obtained from FDA.gov.