Software fault tolerance for distributed object based computing

Abstract

Providing resiliency from software failures requires design diversity. Multi-versioning the software components provides the required diversity. Distributed object based computing (DOC) uses the distributed nature of objects to build a distributed software composed of software components that are encapsulated and reusable. Taking advantage of the redundant computing resources available in the distributed environment, DOC can provide resilience from hardware failures by replicating objects. In this paper, we discuss the technique that provides software fault tolerance in addition to hardware fault tolerance. The technique uses the encapsulation property of objects to provide a group of concurrently executing objects that all share a common interface but have different implementations. The objects in the group appear to the client as if they are a single object since they all respond to the same request from the same interface at the same time. The application layer implementation of the technique is possible since no hardware or operating system level support is necessary.