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The fifty percent rule revisited

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Abstract

Combinatorial reasoning is applied to the analysis of two kinds of dynamic storage allocation system to derive results about the degree and characteristics of memory fragmentation. The simple first-fit scheme with immediate replacement, discussed by Knuth, is analyzed further, providinginter alia a new derivation of the “fifty percent rule”. Next a system with garbage collections is considered, and the mean and variance of the number of holes following a garbage collection are determined, along with other results. The cell distributions resulting from these two idealized policies are contrasted.

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Authors and Affiliations

  1. Department of Computer Science, The University of Western Ontario, N6A 5B9, London, Ontario, Canada

    D. Julian & M. Davies

Authors
  1. D. Julian
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  2. M. Davies
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Additional information

This research was supported in part by the National Science and Engineering Research Council of Canada under an operating grant.

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Julian, D., Davies, M. The fifty percent rule revisited. BIT 20, 279–288 (1980). https://doi.org/10.1007/BF01932770

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  • DOI: https://doi.org/10.1007/BF01932770

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