Reversible Communicating Systems

Abstract

One obtains in this paper a process algebra RCCS, in the style of CCS, where processes can backtrack. Backtrack, just as plain forward computation, is seen as a synchronization and incurs no additional cost on the communication structure. It is shown that, given a past, a computation step can be taken back if and only if it leads to a causally equivalent past.

Causal-Consistent Reversibility in a Tuple-Based Language

“…Of course, this is not desired when the processes are accessing a shared resource in read-only modality. This is nevertheless the behavior obtained if the resource is, e.g., a message in ρπ [14] or an output process in [5], [18], [4].…”

“…This observation led to the concept of causalconsistent reversibility: one may undo any action if no other action depending on it has been executed (and not undone). Building on this definition, reversible extensions of many concurrent calculi and languages have been defined, e.g., for CCS [5], [18], π-calculus [4], higher-order π [14] and µOz [17]. However, to figure out how to make a general programming language reversible, the interplay between reversibility and many common language features has still to be understood.…”

Retractable and Speculative Contracts

“…The semantics defined above for retractable client/server pairs can be seen as an instantiation on contracts of the standard reversible semantics for process calculi, see, e.g., [17,29,25,26]. In particular, the semantics would become a classic uncontrolled semantics (according to the terminology in [26]) by removing the four control mechanisms below:…”

Events, Causality and Symmetry

“…Causal models, their equivalences and logics are making a surprising appearance in reversible computation [27,77].…”