Method of reducing the complexity of an I/O request to a RAID-4 or RAID-5 array
US5519849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1994 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Oct 25, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/0689
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Data storage systems using a RAID-4 or RAID-5 organization divide an application I/O request into a number of individual I/O requests, each of which is contained within the boundaries of a single strip. The data blocks of each chunk on a strip responsive to an I/O request can form a complex geometric pattern requiring complicated operations to perform the I/O request. To simplify the necessary operations, each individual I/O request to a strip is divided into at most three requests targeted to data blocks forming a rectangle and each of these rectangles are processed as a unit. If a data block within a rectangle is unavailable, then the request to that rectangle is further subdivided into at most two requests targeted to data blocks forming smaller, non-overlapping rectangles which collectively are the original rectangle. The recursive decomposition of rectangles into smaller rectangles isolates the data block with an error and permits the selection of fewer and less complicated operation algorithms to complete the I/O request.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.