Stochastic modeling of multiprocessor reliability

Colored Petri nets have been shown to create greatly simplified models that have many fewer places and transitions and can be applied to families of systems with minimal changes. The paper presents a modeling tool that uses a form of colored stochastic Petri nets to model the performance of fault tolerant multicomputers as resources fail. The model can be viewed as having tokens that collect to form compound tokens in a manner somewhat analogous to the formation of molecules from atoms. Therefore we call it the Polyvalent Stochastic Petri Net (PSPN) modeling system. Using this approach simple and relatively similar models can be used for systems of varying sizes and configuration. Complex actions such as backtracking and routing around failed links in a communications system can be expressed in the transitions. Failed parts are modeled by simply removing a resource token from a place