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Efficiency of file synchronization in a linear tape file system

  • US 9,940,338 B2
  • Filed: 06/03/2016
  • Issued: 04/10/2018
  • Est. Priority Date: 12/04/2013
  • Status: Active Grant
First Claim
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1. A method, in a data processing system, for improved file synchronization of a magnetic tape, the method comprising:

  • upon receiving one or more file checksums from a destination device, setting, by the source device, a value of an offset variable and a value of a disagree_length variable to 0;

    determining, by the source device, whether a sum of the value of the offset variable, the value of the disagree_length variable, and a predefined value of a block_length is less than or equal to a size of a modified version of the identified file thereby forming a new file, wherein the predefined value of the block_length is a length of a fixed-length block to calculate checksum;

    responsive to the determining that the sum of the value of the offset variable, the value of the disagree_length variable, and the predefined value of the block_length is greater than the size of the new file, transmitting, by the source device, the data equivalent to the difference of the size of the new file minus the offset from the value of the offset as a literal instruction to the destination device;

    segmenting, by the source device, data of the new file into fixed-length blocks that do not overlap one another;

    calculating, by the source device, one or more new file checksums for each of the fixed-length blocks;

    transmitting, by the source device, the one or more new file checksums to the destination device; and

    storing, by the destination device, the one or more new file checksums in the extended file attributes associated with the new file in the index associated with the magnetic tape in the local data structure.

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