CONSISTENT OBJECT REPLICATION IN THE ETERNAL SYSTEM

The Eternal system replicates CORBA objects to provide fault tolerance , high availability, and evolution of live objects. By exploiting the IIOP interface, Eternal renders the replication transparent to the app lication objects, and also to the ORE and thus works with standard com mercial CORBA ORBs. To maintain replica consistency, Eternal uses oper ations communicated in totally ordered multicast messages, detection o f duplicate invocations and duplicate responses, transfer of state bet ween the object replicas, consistent scheduling of concurrent operatio ns, and fulfillment operations for restoring a consistent state after network partitioning and remerging. The difficult issues of replicatio n, consistency, fault detection, and recovery are handled by Eternal a nd are hidden from the application programmer. (C) 1998 John Wiley & S ons, Inc.