Quorum-based locking protocol for replicated objects

In order to make an object based system fault tolerant, objects are replicated. We discuss a novel object based locking (OBL) protocol to lock replicated objects by extending the traditional quorum based protocols to abstract methods. If a pair of methods op/sub 1/ and op/sub 2/ are compatible, the quorums for op/sub 1/ and op/sub 2/ do not intersect in the OBL protocol, even if op/sub 1/ or op/sub 2/ updates the object. We propose a version vector to identify which methods are performed on a replica. We discuss the OBL protocol where the replicas exchange the compatible methods by using the version vector.