Rollback based on vector time

Causality, as made concrete by Lamport's "happened before" relation, is the central underlying basis in the design of optimistic protocols for checkpoint and recovery. After the recovery of a formerly failed process, all events and messages which causally follow the events and messages discarded by restoration of a state checkpoint must be discarded also. The isomorphism between causality and vector time is well-known. That isomorphism is exploited here in order to develop and verify a simple and effective protocol which explicitly uses the causal partial order, through the use of vector time, in order to rollback a computation in response to a process failure.<
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