High-Level Requirements
HLRSection 08: Software Certification (DO-178C)
Definition
Software requirements that are developed directly from the system requirements allocated to the software item. High-level requirements specify the functional behavior, performance characteristics, timing constraints, interface definitions, and safety-related requirements of the software item in terms that are implementation-independent. HLRs describe what the software must do, not how it does it. Each HLR must be traceable to the system requirement(s) from which it was derived. HLRs that are not traceable to system requirements are classified as derived requirements and must be evaluated for their safety impact.
Where This Shows Up
HLRs are the starting point of the software development process under DO-178C. They define the software's required behavior at a level above the implementation. The quality of HLRs — their accuracy, unambiguity, verifiability, and completeness — directly affects the quality of the downstream design, code, and tests. DO-178C requires that HLRs be reviewed for accuracy, consistency, verifiability, conformance to standards, traceability, and algorithm accuracy.
Primary Sources
Defines the software requirements process including high-level requirements development and review objectives.
Artifacts Produced
Document containing the high-level requirements for the software item, including functional, performance, interface, and safety requirements.
Related Terms
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