Reliability of fully and partially replicated systems

The reliability of two replication methods, partial and full, is analyzed for a two-process/four-processor case. Three types of systems are analyzed and compared: no repair, finite repair-rate and instantaneous repair. These systems are modeled using discrete-state continuous-time Markov chains. The condition under which a partially replicated system might yield a better reliability than that of a fully replicated system is quantified and expressed in terms of system design parameters. Partial replication is most favorable in systems without repair capability and this advantage is manifested most when the underlying hardware is unreliable.<
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