An Efficient Optimistic Message Logging Scheme for the Recoverable Mobile Computing Systems

This paper presents an efficient scheme to implement the optimistic message logging and the asynchronous recovery for the mobile computing environment. Most of the coordinated checkpointing schemes may not be suitable for the mobile environment, since the unreliable mobile hosts and the fragile network connection may hinder any kind of coordination for checkpointing and recovery. In this paper, optimistic message logging is used with the independent checkpointing. To reduce the logging overhead imposed on mobile hosts, mobile support stations take care of message logging and dependency tracking; and mobile hosts maintain only a small amount of information for the mobility tracking. As a result, asynchronous recovery for the mobile computing systems can be achieved with the little overhead. The performance of the proposed scheme is evaluated and the simulation results show that with the reasonable overhead, fault-tolerant mobile computing systems can be implemented based on the optimistic message logging.