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US006629199B1
(12) United States Patent ao) Patent No.: us 6,629,199 Bi
Vishlitzky et al. (45) Date of Patent: Sep. 30,2003
(54) DIGITAL DATA STORAGE SYSTEM INCLUDING DIRECTORY FOR EFFICIENTLY PROVIDING FORMATTING INFORMATION FOR STORED RECORDS AND UTILIZATION OF A CHECK VALUE FOR VERIFYING THAT A RECORD IS FROM A PARTICULAR STORAGE LOCATION
(75) Inventors: Natan Vishlitzky, Brookline, MA (US);
Haim Kopylovitz, Brookline, MA (US)
(73) Assignee: EMC Corporation, Hopkinton, MA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/378,643
(22) Filed: Aug. 20, 1999
(51) Int. CI.7 G06F 12/00
(52) U.S. CI 711/113; 711/112; 711/207;
711/208; 711/209; 714/758; 714/769
(58) Field of Search 711/112, 113,
711/207, 208, 209; 714/758, 769
(56) References Cited
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OTHER PUBLICATIONS
Advanced Micro Devices (AMD), AM 2960 Family Handbook, 1983, pp 36^15.*
* cited by examiner
Primary Examiner—Hong Kim
(74) Attorney, Agent, or Firm—Fish & Richardson PC. (57) ABSTRACT
A digital data storage system in the form of a mass storage subsystem in which information is stored on one or more disk storage units, with a storage element constituting a track on a disk storage device and each track storing a plurality of records. Each track in each disk storage device of the digital data storage system is associated with a descriptor. When the control device retrieves the contents of a record, it can process the contents to generate a check value and compare the generated check value with the check value for the record as stored in the descriptor associated with the track. If they compare appropriately, the control device can determine that the record that was retrieved was, in fact, the record that was to be retrieved. On the other hand, if they do not compare appropriately, the control device can determine that the record that was retrieved was not the proper record. If the contents of the record are updated, the control device can update the check value in the descriptor to reflect the update of the record.
6 Claims, 6 Drawing Sheets
