Dependability of fault-tolerant systems-explicit modeling of the interactions between hardware and software components

This paper addresses the dependability modeling of hardware and software fault-tolerant systems taking into account explicitly the interactions between the various components. It presents a framework for modeling these interactions based on Generalized Stochastic Petri Nets (GSPNs). The modeling approach is modular: the behavior of each component and each interaction is represented by its own GSPN, while the system model is obtained by composition of these GSPNs. The composition rules are defined and formalized through clear identification of the interfaces between the component and the dependency nets. In addition to modularity, the formalism brings flexibility and re-usability. This approach is applied to a simple, but still representative, example.