Optimized stripe detection for redundant arrays of disk drives
August 12, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesCache/disk subsystem with dual aging of cache entries Automatic adjustment of the quantity of prefetch data in a disk cache operation Method and apparatus for grouping asynchronous recording operations Sequentially processing data in a cached data storage system Method of handling disk sector errors in DASD cache Memory disk accessing apparatus Method for transferring data between memories Disk drive control unit having sets of operating command and operation length information and generating end signal based upon operation length information Method and means for accessing DASD arrays with tuned data transfer rate and concurrency Storage device array architecture with copyback cache Patent #: 5274799 InventorsAssigneeApplicationNo. 929076 filed on 08/12/1992US Classes:714/766Check bits stored in separate area of memoryExaminersPrimary: Canney, Vincent P.Attorney, Agent or FirmInternational ClassG06F 011/10AbstractA system for reducing the number of I/O requests required to write data to an redundant array of inexpensive disks (RAID) of a computer system including a host central processor unit and a memory buffer cache. The system includes determinations for writing new data stored in the cache to the disk drives, as stripes, using the least number of I/O requests possible. The system uses the best of two alternative techniques in which the parity for the stripe can be generated. A first procedure determines the number of I/O requests that would be required to generate the parity data from the entire stripe including the new data to be written to the disk drives. A second procedure determines the number of I/O requests that would be required to generate the parity data from the new data to be written to the disk drives and the old parity data of the stripe. The system then aggregates in memory the blocks necessary to generate the parity data as either an entire stripe or as individual blocks using the technique which requires the least number of I/O requests as determined by the first and second procedures.Other References
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