Toward Improved Verification And Certification of Legacy Systems

Existing standards for dependable systems, and in particular DO-178B for commercial flight software and DO-254 for flight hardware, are best suited to “clean sheet of paper” designs for entirely new systems. Yet, in industry – and in particular for safety-critical systems – entirely new designs are relatively rare, and generally entail very high risks in both financial and performance terms. This paper briefly surveys the state of the art in methods for certifying legacy (or COTS) systems, and proposes improved procedures for the future, including the increased use of formal verification methods to enhance dependability. As standards evolve, these procedures may ameliorate the very high current cost and risk associated with present compliance requirements.