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Lookup NU author(s): Professor Maciej KoutnyORCiD
The application of N-Modular Redundancy (NMR) in the contruction of software permits redundant systems to be robust with respect to failures in replicated processors. In order to exhibit consistent behaviour, all processors in an MNR node must process input requests in the same order. This paper investigates the introduction of synchronization points among replicated computations in a nondeterministic model for concurrent programming. A formal specification is given of a distributed synchronization mechanism that does not introduce any additional deadlock in the replication of a basic single system. We propose this synchronization mechanism as a means of preventing the occurence of the so-called sequencing failures. The properties of the proposed solution are specified and proved using the COSY path expression formalism. Finally, some implementation schemes are proposed which satisfy the given specification.
Author(s): Koutny M, Mancini LV
Publication type: Report
Publication status: Published
Series Title: Computing Laboratory Technical Report Series
Year: 1987
Pages: 38
Report Number: 237
Institution: Computing Laboratory, University of Newcastle upon Tyne
Place Published: Newcastle upon Tyne
URL: http://www.cs.ncl.ac.uk/publications/trs/papers/237.pdf
