Property coverage for quality assessment of fault tolerant or failsafe systems

In the design environment, system properties, such as fault tolerance and safe operation, need to be demonstrated in new product development of safety-critical systems. The onus of the proofs is by no means trivial, and the associated computational cost can be overwhelming. In this paper, a novel quality metrics is introduced, property coverage (PC), which allows, with affordable computational effort, to have a measure of the degree of confidence within which the property under evaluation holds. The proposed method uses fault sampling, and enables PC evaluation with limited fault list sizes. The methodology and associated metrics are ascertained through a case study, an ASIC for safety-critical gas burner control system, recently certified to be compliant to EN 298 safety standard.