Object replication using version vector

In object-based systems, objects supporting abstract methods are replicated to increase the performance, reliability and availability. We discuss a novel object-based locking (OBL) protocol to lock replicas of objects by extending the quorum-based protocol for read and write to abstract methods. Unless two methods conflict, subsets of the replicas locked by the methods do not intersect even if the methods change the replicas. Methods not computed on a replica A but computed on another replica are computed on A when a method conflicting with the methods are issued to A in the OBL protocol. We newly propose a version vector to identify what methods are computed on a replica.