ChaRM is a checkpoint-based backward fault recovery and process migration system. It is designed to recovery the fault of NOWs (networks of workstations) by checkpointing and rollback recovery. It offers functions of on-line software and hardware maintenance, process migration and load balance, etc. ChaRM is able to run on NOWs that change over time due to failure, load or availability. As long as there is at least one node alive in the cluster, the computation will complete in an efficient manner. The checkpointing, rollback recovery and process migration techniques, and some performance evaluation results are discussed in this paper.