Three Phase Coordinated Checkpointing Scheme for Mobile Distributed Systems

In this paper, a three phase minimum-process coordinated checkpointing algorithm for nondeterministic mobile distributed systems is proposed, where no useless checkpoints are taken. An effort has been made to minimize the blocking of processes and synchronization message overhead and to capture the partial transitive dependencies during the normal execution by piggybacking dependency vectors onto computation messages. Frequent aborts of checkpointing procedure may happen in mobile systems due to exhausted battery, non-voluntary disconnections of MHs, or poor wireless connectivity. Therefore, in the proposed scheme, all concerned MHs will take ad-hoc checkpoint only and these checkpoint is stored on the memory of MH only. In this case, if some process fails to take checkpoint in the first phase, then MHs need to abort their ad-hoc checkpoints only. In this way, we try to minimize the loss of checkpointing effort when any process fails to take its checkpoint in coordination with others. Keyword--Checkpointing, Ad-hoc checkpoint, Mobile Host, Mobile Support System