Verification and Validation Guidelines for High Integrity Systems.

Abstract : Software verification and validation (VV both the nuclear and defense communities will benefit from it. A risk-based classification scheme was developed for high integrity systems. Risk is made a function of probability of failure and the severity of consequences associated with failure. The intent is to tailor the level of V&V according to the classification. An error classification scheme was developed for use with a database of failure modes and failure rates of existing systems. The intent is to enable a more objective evaluation of software V&V methodologies. The application of quality metrics to the high integrity software development process was explored. High integrity software verification guidance was developed for several methodologies, including reviews and audits, independent equivalent activities, backward reconstruction and algebraic methods. Verification over the entire life cycle is addressed. Two new tools, the Enhanced Condition Table Tool and the Code Analyzer Tool Set, are explored as methods of verification completely independent of the software developer. A combination of functional, structural, and statistical testing is (see reverse) recommended for validation. Issues covered relative to validation include how much testing is required, i.e., termination criteria and what other concerns should be addressed during validation.