This version of SWEHB is associated with NPR 7150.2B. Click for the latest version of the SWEHB based on NPR7150.2D

The following content is taken verbatim from NPR 7150.2B, NASA Software Engineering Requirements, Appendix A, which can be accessed through this NODIS web page.

Appendix A. Definitions

Accredit. The official acceptance of a software development tool, model, or simulation (including associated data) to use for a specific purpose.

Analysis. The post-processing or interpretation of the individual values, arrays, files of data, or execution information. It is a careful study of something to learn about its parts, what they do, and how they are related to each other.

Bidirectional Traceability. Association among two or more logical entities that is discernible in either direction (to and from an entity). (ISO/IEC/IEEE 24765 Systems and software engineering-Vocabulary)

Computer. Functional unit that can perform substantial computations, including numerous arithmetic operations and logic operations.

Computer Software Configuration Item. An aggregation of software that is designated for configuration management and treated as a single entity in the configuration management process.

Computer System. A system containing one or more computers and associated software. (Source: ISO/IEC/IEEE 24765 Systems and software engineering-Vocabulary)

Contracted Software. Software created for a project by a contractor or subcontractor.

Data. Information for computer processing (e.g., numbers, text, images, and sounds in a form that is suitable for storage in or processing by a computer).

Deviation. A documented authorization releasing a program or project from meeting a requirement before the requirement is put under configuration control at the level the requirement will be implemented.

Embedded Computer System. A computer system that is part of a larger system and performs some of the requirements of that system. (Source: ISO/IEC/IEEE 24765 Systems and software engineering-Vocabulary)

Embedded Software. Software that is part of a larger system and performs some of the requirements of that system. (Source: ISO/IEC 24765 Systems and software engineering- Vocabulary)

Establish and Maintain. Formulation, documentation, use/deployment, and current maintenance of the object (usually a document, requirement, process, or policy) by the responsible project, organization, or individual.

Glueware. Software created to connect the off-the-shelf software/reused software with the rest of the system. It may take the form of "adapters" that modify interfaces or add missing functionality, "firewalls" that isolate the off-the-shelf software, or "wrappers" that check inputs and outputs to the off-the-shelf software and may modify to prevent failures.

Government Off-the-Shelf Software. This refers to Government-created software, usually from another project. The software was not created by the current developers (see software reuse). Usually, source code is included and documentation, including test and analysis results, is available; e.g., the Government is responsible for the Government off-the-shelf (GOTS) software to be incorporated into another system.

Highly Specialized Information Technology. Highly Specialized IT is a part of, internal to, or embedded in a mission platform. The platform's function (e.g., avionics, guidance, navigation, flight controls, simulation, radar, etc.) is enabled by IT but not driven by IT itself (e.g., computer hardware and software to automate internal functions of a spacecraft or spacecraft support system such as spacecraft control and status, sensor signal and data processing, and operational tasking.) Highly Specialized IT acquisitions may include full development (where the information technology is a primary issue) to modification of existing systems (information architecture is firm and demonstrated in an operational environment) where information technology is not an issue. Real time is often critical -- and few opportunities exist to use Commercial Off The Shelf (COTS) or Government Off The Shelf (GOTS) beyond microprocessors and operating systems because these systems are largely unprecedented or largely unique applications. Certain IT considered Mission Critical because the loss of which would cause the stoppage of mission operations supporting real-time on-orbit mission operations is identified as "Highly Specialized" by the Directorate Associate Administrator. Highly Specialized IT is largely custom, as opposed to COTS or commodity IT systems or applications, and includes coding/applications that are integral parts of the research or science requirements, e.g., Shuttle Avionics Upgrade. Common engineering IT tools such as Product Life cycle Management (PLM) systems, Computer-Aided Design (CAD) systems, and collaborative engineering systems and environments are not Highly Specialized IT. Representative examples of Highly Specialized IT include: Avionics software, real-time control systems, onboard processors, Deep Space Network, spacecraft instrumentation software, wind tunnel control system, human physiology monitoring systems, ground support environment, experiment simulators, Mission Control Center, and Launch cameras. (Source: NPR2800.1, Managing Information Technology)

Independent Verification and Validation. Verification and validation performed by an organization that is technically, managerially, and financially independent of the development organization. (Source: ISO/IEC 24765 systems and software engineering vocabulary)

Information Technology. Any equipment or interconnected system(s) or subsystem(s) of equipment that is used in the automatic acquisition, storage, analysis, evaluation, manipulation, management, movement, control, display, switching, interchange, transmission, or reception of data or information by the Agency (reference FAR 2.101). (Source: NPR2800.1, Managing Information Technology)

Insight. An element of Government surveillance that monitors contractor compliance using Government-identified metrics and contracted milestones. Insight is a continuum that can range from low intensity such as reviewing quarterly reports to high intensity such as performing surveys and reviews. (Source: NPR 7123.1B)

Legacy and Heritage. Software products (architecture, code, requirements) written specifically for one project and then, without prior planning during its initial development, found to be useful on other projects. See software reuse.

Major Engineering/Research Facility. Used in this document to show research, development, test, or simulation facilities representing a significant NASA investment (facilities with a Current Replace Value (CRV) equal to or greater than 50 million dollars) which contains software that supports programs and projects managed under NPR 7120.5, NPR 7120.7, or NPR 7120.8 and that have a Mission Dependency Index value equal to or greater than 70.

Mission Critical. Item or function that should retain its operational capability to assure no mission failure (i.e., for mission success - meeting all mission objectives and requirements for performance and safety). (Source: NPR 8715.3)

Model. A description or representation of a system, entity, phenomena, or process. (Source: NASA-STD-7009) Only for the purpose of this document, the term "model" refers to only those models that are implemented in software.

Modified Off-the-Shelf Software. When COTS or legacy and heritage software is reused, or heritage software is changed, the product is considered "modified." The changes can include all or part of the software products and may involve additions, deletions, and specific alterations. An argument can be made that any alterations to the code and/or design of an off-the-shelf software component constitutes "modification," but the common usage allows for some percentage of change before the off-the-shelf software is declared to be modified off-the-shelf (MOTS) software. This may include the changes to the application shell and/or glueware to add or protect against certain features and not to the off-the-shelf software system code directly. See off-the-shelf software.

Off-the-Shelf Software. Software not developed in-house or by a contractor for the specific project now underway. The software is generally developed for a purpose different from the current project. Used in practice as umbrella for COTS, GOTS, and MOTS.

Open-Source Software. Software where its human-readable source code is made broadly available without cost under an OSS license, which provides conditions on use, reuse, modification/improvement, and redistribution; and often where the software development, management, and planning is done publicly, or easily observable by an individual or organization not previously connected with its open source project.

Operational Software. Software that has been accepted and deployed, has been delivered to its customer, or is deployed in its intended environment.

Primary Mission Objectives. Outcomes expected to be accomplished, which are closely associated with the reason the mission was proposed, funded, developed, and operated (e.g., objectives related to top-level requirements or their flow down).

Process Asset Library. A collection of process asset holdings that may be used by an organization or project. (Source: CMMI® for Systems Engineering/Software Engineering/Integrated Product and Process Development Supplier Sourcing)

Program. A strategic investment by a Mission Directorate or Mission Support Office that has a defined architecture and/or technical approach, requirements, funding level, and a management structure that initiates and directs one or more projects. A program defines a strategic direction that the Agency has identified as critical.

Project. A specific investment having defined goals, objectives, requirements, life-cycle cost, a beginning, and an end. A project yields new or revised products or services that directly address NASA's strategic needs. They may be performed wholly in-house; by Government, industry, academia partnerships; or through contracts with private industry.

Risk Management. An organized, systematic decision-making process that efficiently identifies, analyzes, plans, tracks, controls, communicates, and documents risk to increase the likelihood of achieving program/project goals. (Source: NPR 8715.3)

Safety-Critical Software. See description in NASA-STD-8719.13.

Scripts. A sequence of automated computer commands embedded in a program that tells the program to execute a specific procedure (e.g., files with monitoring, logic, or commands used by software to automate a process or procedure).

Simulation. The imitation of the characteristics of a system, entity, phenomena, or process using a computational model. (Source: NASA-STD-7009) Only for the purpose of this document, the term "simulation" refers to only those simulations that are implemented in software.

Software. Computer programs, procedures, scripts, rules, and associated documentation and data pertaining to the development and operation of a computer system. This definition applies to software developed by NASA, software developed for NASA, commercial-off-the-shelf (COTS) software, Government-off-the-shelf (GOTS) software, modified-off-the-shelf (MOTS) software, reused software, auto-generated code, embedded software, the software executed on processors embedded in Programmable Logic Devices (see NASA-HDBK-4008), and open-source software components.

Software Architecture. The software architecture of a program or computing system is the structure or structures of the system, which comprise software components, the properties of those components, and the relationships between them. The term also refers to documentation of a system's software architecture. Documenting software architecture facilitates communication between stakeholders, documents early decisions about high-level design, and allows reuse of design components and patterns between projects.

Software Assurance. The planned and systematic set of activities that ensure that software life- cycle processes and products conform to requirements, standards, and procedures. For NASA, this includes the disciplines of software quality (functions of software quality engineering, software quality assurance, and software quality control), software safety, software reliability, software verification and validation, and IV&V.

Software Engineering. The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, i.e., the application of engineering to software. (Source: IEEE 24765, Systems and software engineering-Vocabulary, paragraph 3.2760)

Software Item. Source code, object code, control code, control data, or a collection of these items.

Software Peer Review and Inspection. A visual examination of a software product to detect and identify software anomalies, including errors and deviations from standards and specifications. (Source: IEEE 1028, IEEE Standard for Software Reviews and Audits). Refer to NASA-STD-8739.9 for guidelines for software peer reviews or inspections.

Software Reuse. A software product developed for one use but having other uses or one developed specifically to be usable on multiple projects or in multiple roles on one project. Examples include, but are not limited to, COTS products, acquirer-furnished software products, software products in reuse libraries, and pre-existing developer software products. Each use may include all or part of the software product and may involve its modification. This term can be applied to any software product (such as requirements and architectures), not just to software code itself. Often, this is software previously written by an in-house development team and used on a different project. GOTS software would come under this category if the product is supplied from one Government project to another Government project.

Software Validation. Confirmation that the product, as provided (or as it will be provided), fulfills its intended use. In other words, validation ensures that "you built the right thing." (Source: IEEE 1012, IEEE Standard for Software Verification and Validation)

Software Verification. Confirmation that work products properly reflect the requirements specified for them. In other words, verification ensures that "you built it right." (Source: IEEE 1012, IEEE Standard for Software Verification and Validation)

Static Analysis. The process of evaluating a system or component based on its form, structure, content, or documentation. (Source: ISO/IEC 24765, Systems and software engineering vocabulary)

Subsystem. A secondary or subordinate system within a larger system. (Source: ISO/IEC 24765, Systems and software engineering-Vocabulary)

System. The combination of elements that function together to produce the capability required to meet a need. The elements include hardware, software, equipment, facilities, personnel, processes, and procedures needed for this purpose. (Source: NPR 7123.1)

Tailoring. The process used to adjust or seek relief from a prescribed requirement to accommodate the needs of a specific task or activity (e.g., program or project). The tailoring process results in the generation of deviations and waivers depending on the timing of the request.

Uncertainty. (1) The estimated amount or percentage by which an observed or calculated value may differ from the true value. (2) A broad and general term used to describe an imperfect state of knowledge or a variability resulting from a variety of factors including, but not limited to, lack of knowledge, applicability of information, physical variation, randomness or stochastic behavior, indeterminacy, judgment, and approximation. (Source: NPR 8000.4)

Unit Test. (1) Testing of individual routines and modules by the developer or an independent tester (ISO/IEC/IEEE 24765 Systems and software engineering--Vocabulary) (2) A test of individual programs or modules in order to ensure that there are no analysis or programming errors (ISO/IEC 2382-20 Information technology--Vocabulary--Part 20: System development, 20.05.05) (3) Test of individual hardware or software units or groups of related units. (ISO/IEC/IEEE 24765 Systems and software engineering--Vocabulary)

Waiver. A documented authorization releasing a program or project from meeting a requirement after the requirement is put under configuration control at the level the requirement will be implemented.

Wrapper. See glueware definition.

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