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An Optimal Strategy for Comparing File Copies
January 1994 (vol. 5 no. 1)
pp. 87-93

We study the problem of identifying corrupted pages between two remotely locatedcopies of a file in a distributed system. An efficient deterministic algorithm is presented to identify up to any given number of differing pages. The algorithm requires a singleexchange of messages and is based on the structure of the Reed-Solomon code. In orderto identify up to f corrupted pages, 2f signatures are transmitted. The algorithm requiresless communication costs than previously proposed solutions. In fact, we prove that ouralgorithm is optimal, in the sense that no other algorithm is guaranteed to identify withprobability 1 the corrupted pages by exchanging less information.

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Index Terms:
Index Termsdata integrity; Reed-Solomon codes; distributed databases; fault tolerant computing;optimal strategy; comparing file copies; corrupted pages; distributed system;deterministic algorithm; Reed-Solomon code
K.A.S. Abdel-Ghaffar, A. El Abbadi, "An Optimal Strategy for Comparing File Copies," IEEE Transactions on Parallel and Distributed Systems, vol. 5, no. 1, pp. 87-93, Jan. 1994, doi:10.1109/71.262591
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