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Method and means for cataloging data sets using dual keyed data sets and direct pointers

  • US 4,408,273 A
  • Filed: 05/27/1980
  • Issued: 10/04/1983
  • Est. Priority Date: 05/27/1980
  • Status: Expired due to Term
First Claim
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1. A method for operating a computing system under control of a catalog management facility referencing a catalog data set residing on a first data volume to open a user data set residing on a second data volume, where said first or second data volume may have been changed by events external to the catalog management facility, resulting in loss of synchronization between said user data set and said catalog data set, comprising the steps of;

  • searching said catalog data set for a first record keyed to said user data set, said first record including a pointer to a second record in a volume data set residing on said second data volume;

    responsive to said pointer, retrieving said second record;

    testing the key of said second record to detect a loss of synchronization; and

    ,if said second record is keyed to said user data set and thus indicates synchronization, opening the user data set described by said second record;

    otherwise, searching said volume data set in said second data volume to retrieve a third record keyed to said user data set, and upon locating said third record, updating said pointer to reestablish synchronization between said pointer and said user data set, and opening the user data set described by said third record;

    whereby said user data set is opened without signaling an error to the user even though loss of synchronization has previously resulted from an external event such as a restoration of said first data volume or said second data volume from an archival data volume.

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