A pessimistic consistency control algorithm for replicated files which achieves high availability

A consistency control algorithm is described for managing replicated files in the face of network partitioning due to node or communication link failures. It adopts a pessimistic approach in that mutual consistency among copies of a file is maintained by permitting files to be accessed only in a single partition at any given time. The algorithm simplifies the Davcev-Burkhard dynamic voting algorithm (1985) and also improves its availability by adding the notion of linearly ordered copies. A proof that any pessimistic algorithm with fresh reads is one-copy serializable is given.<
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