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Active Replication of Distributed Programs: Problems and Solutions

Lookup NU author(s): Emeritus Professor Santosh Shrivastava, Dr Alan Tully



Replicated execution of distributed programs provides a means of masking hardware (processor) failures in a distributed system. Application level entities (processes, objects) are replicated to execute on distinct processors. Non-deterministic program constructs within the replicas could cause messages to be processed in non-identical order, or computations to choose different execution paths producing divergence of states. The replicas could thereafter produce inconsistent responses to identical messages and hence appear to be faulty. We identify possible sources of non-determinism and present general solutions for ensuring that non-faulty replicas process messages in identical order and follow identical execution paths in their computations thereby preventing state divergence. Particular attention is paid to real-time programs which can contain a variety of non-deterministic program constructs.

Publication metadata

Author(s): Shrivastava SK, Tully A

Publication type: Report

Publication status: Published

Series Title: Department of Computing Science Technical Report Series

Year: 1993

Pages: 25

Print publication date: 01/03/1993

Source Publication Date: March 1993

Report Number: 418

Institution: Department of Computing Science, University of Newcastle upon Tyne

Place Published: Newcastle upon Tyne