CSP Methods for IdentiQing Atomic Actions in the Design of Fault Tolerant Concurrent Systems

Limiting the extent of error propagation when faults occur and localizing the subsequent error recovery are common concerns in the design of fault tolerant parallel processing systems. Both activities are made easier if the designer associates fault tolerance mechanisms with the underlying atomic actions of the system. With this in mind, this paper has investigated two methods for the identification of atomic actions in parallel processing systems described using CSP. Explicit trace evaluation forms the hasis of the first algorithm, which enables a designer to analyze interprocess communications and thereby locate atomic action boundaries in a hierarchical fashion. The second method takes CSP descriptions of the parallel processes and uses structural arguments to infer the atomic action boundaries. This method avoids the difficulties involved with producing full trace sets, but does incur the penalty of a more complex algorithm. Index Term-Atomic actions, concurrent systems, CSP, fault tolerance.