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Multilevel, hierarchical, dynamically mapped data storage subsystem

  • US 5,155,835 A
  • Filed: 11/19/1990
  • Issued: 10/13/1992
  • Est. Priority Date: 11/19/1990
  • Status: Expired due to Term
First Claim
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1. Apparatus for automatically archiving infrequently used data records onto more economical media in a dynamically mapped data storage subsystem that stores data records for at least one associated host processor, said dynamically mapped data storage subsystem including a plurality of disk drive devices, where the dynamically mapped data storage subsystem writes a stream of data records received from one of said associated host processors in available memory space on said disk drive devices, comprising:

  • cache memory means connected to and interconnecting said host processors and said disk drive devices for storing data records transmitted therebetween;

    tape drive archive memory means connected to said cache memory means for storing data records that were previously stored on said disk drive devices by said associated host processors;

    means, responsive to said host processor storing one of said data records in a first available memory location on said disk drive devices, for maintaining a count of the frequency of said host processor access of said one data record stored in said first available memory location on said disk drive devices;

    means for comparing said maintained count to a predetermined threshold;

    means, responsive to said threshold exceeding said count, for signifying said data record stored in said first available memory location on said disk drive devices as archivable;

    means for transferring said archivable data record from said first available memory location on said disk drives to said cache memory means for archiving; and

    means, responsive to said archivable data record being transferred into said cache memory means, for rewriting said cached archivable data record stored from said cache memory means into said tape drive archive memory means.

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