ENSURING VALUE LIVENESS of DISTRIBUTED SOFTWARE THROUGH CHANGELING†

This paper extends the Changeling methodology, which ensures safety of concurrent and distributed software, to provide responsiveness properties. Changeling employs formal methods to generate executable assertions which ensure that the physical state, in the actual run time environment, is consistent with the logical state specified in the assertion. The focus, here, is on the generation of executable assertions from value liveliness properties established in the temporal specifications. Specifically, a translation process was developed to generate run-time-assured programs. The verification tool adopted by Changeling is Interleaving Set Temporal Logic (ISTL) since the logic is based on partial order semantics and capable of expressing the intermediate assertions(behavior) of distributed programs. The translation is shown to be sound and relatively complete; an example of ensuring value liveliness properties is presented for distributed Branch and Bound type problems.