Verifying fault-tolerant behavior of state machines

Fault tolerant behavior is an important non functional requirement for systems that involve high criticality. We present a framework which allows the analysis of fault tolerant behavior to be undertaken. This framework is based on the notion of state machines and tolerance relations. Results concerning fault tolerant behavior of finite state machines are presented and an illustrative example is discussed. Various kinds of fault tolerant behavior (masking, fail-stop, t-fail-stop, degradable, etc.) are modeled.