The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 24, 1994
Filed:
Aug. 12, 1992
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A 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.