Quorum-based protocol for locking replicas of objects

Object-based systems are composed of objects, which are encapsulation of data and methods. Objects are replicated in order to increase reliability and availability of the systems. Objects are manipulated only through the methods. In addition, methods are invoked in a nested manner. We discuss how to lock replicas of an object for methods in a quorum-based scheme and perform methods on the replicas. First, we extend the quorum concept for primitive read and write methods on simple objects like files to abstract methods supported by objects. The quorum size is decided based on a conflicting relation among methods and state updatability of methods