40 Years of Computing at Newcastle

Department Technical Report Series No. 595

Co-ordinated Atomic Actions: from Concept to Implementation

B. Randell, A. Romanovsky, R.J. Stroud, J. Xu and A.F. Zorzo

University of Newcastle upon Tyne. 1997.

Abstract

The Co-ordinated Atomic Action (or CA action) concept is a unified scheme for co-ordinating complex concurrent activities and supporting error recovery between multiple interacting objects in a distributed object-oriented system. It provides a conceptual framework for dealing with different kinds of concurrency and achieving fault tolerance by extending and integrating two complementary concepts - conversations and transactions. Conversations (enhanced with concurrent exception handling) are used to control co-operative concurrency and to implement co-ordinated error recovery whilst transactions are used to maintain the consistency of shared resources in the presence of failures and competitive concurrency.

This paper explains the CA action concept in detail and then addresses related design issues such as multi-thread co-ordination, exception handling and resolution, co-ordinated access to shared objects and provision of software fault tolerance. Finally, brief details are given of a number of experimental prototype implementations and case studies.

Department Technical Report Series - 1997
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Technical Report Abstract No. 595, 30 June 1997