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Database backup method

  • US 4,686,620 A
  • Filed: 07/26/1984
  • Issued: 08/11/1987
  • Est. Priority Date: 07/26/1984
  • Status: Expired due to Term
First Claim
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1. In a distributed data base system having a central computer, a central computer main memory, a central computer mass memory, and a plurality of peripheral data base memories, a method of generating a backup copy of the contents of each of the peripheral data base memories in the central computer mass memory, comprising the steps ofsetting indications of modifications to the stored contents of a peripheral memory as modifications are made,executing a plurality of update passes on each of the peripheral memories, wherein each pass except the last pass includesallowing update modifications to occur to the peripheral memory being backed-up at a given time during execution of the pass,sequentially examining the modification indications and transmitting indicated modifications of the peripheral memory being backed-up at a given time from the peripheral memory to the mass memory,removing indications of modifications as the modifications are transmitted to the mass memory,executing a last update pass on each of the peripheral memories, wherein the last pass includesinhibiting update modifications to the peripheral memory being updated at a given time, andtransmitting all modifications to the peripheral memory being backed-up indicated to be present at the beginning of the last pass to the mass memory.

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