Active Replication of Software Components

This paper considers active replication of distributed objects over CORBA and Java RMI. It describes a replication model and tools whose main purpose is the simplification of the design and implementation of applications with replicated components that intercommunicate to collaborate on a task or to maintain their consistency with client requests. The starting point of this work is Sensei, a group communications system that supports the replication of components as groups of objects working under a virtual synchronous model. It describes the requirements to support the component abstraction, as a key concept to facilitate the development of fault tolerant applications. This model is compared with the replication model defined by OMG for a fault tolerant service in CORBA.