An efficient recovery scheme for fault-tolerant mobile computing systems

This paper presents an efficient recovery scheme to provide fault-tolerance for the mobile computing systems. The proposed scheme is based on the message logging and the independent checkpointing. For the efficient management of the recovery information, such as checkpoints and message logs, the movement-based scheme is suggested. The mobile host carrying its recovery information to the nearby mobile support station can recover instantly in case of a failure. However, the support stations visited by the mobile host may have to experience the high failure-free execution cost for transferring the recovery information and accessing the stable storage. On the other hand, the recovery cost can be too high, if the recovery information remains dispersed over a number of mobile support stations. The movement-based scheme considers both of the failure-free execution cost and the failure-recovery cost. Hence, while a mobile host moves within a certain range, the recovery information of the mobile host remains at the support stations where the information was first saved. However, if the mobile host moves out of the range, it transfers the recovery information into the nearby support station. As a result, the scheme can control the transfer cost as well as the recovery cost. The performance of the proposed scheme is evaluated through the extensive simulation study.