Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Patent
1997-09-30
1999-10-26
Beausoliel, Jr., Robert W.
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
G06F 1100
Patent
active
059745746
ABSTRACT:
A method of checking a large and/or replicated databases includes forming a position sensitive checksum for each entry of the database to be used in the check. The checksums are then exclusive Ored with one another to form a first database checksum. Periodically, the checksums are again created from each of the entries of the check and a second database checksum formed and compared to the first for a match that indicate checked entries of the database have not changed. In another embodiment, a modification to one of the check entries may be provided, accompanied by a master checksum indicative of what the first checksum should be after the entry is modified. The database entry is modified, and a position checksum value for the entry as modified is created. The checksum value for the modified entry, and for the entry before the modification, are exclusive OR with the first checksum value, and that result compared with the master checksum to ensure that the modification was properly made and that the database remains credible.
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Emlich Larry
Johnson Charles W.
Lennie Robert
Lonczak John
Beausoliel, Jr. Robert W.
Elmore Stephen C.
Tandem Computers Incorporated
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