Impossibility of scalar clock-based communication-induced checkpointing protocols ensuring the RDT property

Communication-induced checkpointing protocols constitute an interesting approach to the on-line determination of checkpoint and communication patterns enjoying desirable properties such as domino-effect freedom. They do not add control messages to the computation, but instead may attach control information to computation messages. Among these protocols, scalar clock-based protocols are particularly attractive as they use a single integer as control information. An interesting property of checkpoint and communication patterns is Rollback-Dependency Trackability, which ensures that all local checkpoint dependencies are on-the-fly trackable. So, it would be nice to design scalar clock-based communication-induced checkpointing protocols providing the RDT property, a previously open question. This paper shows that the design of such protocols is impossible. (C) 2001 Elsevier Science B.V. All rights reserved.