Disk array with parity data storage on the radially inner part of each disk
US5737741A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1995 |
| Grant date | Apr 7, 1998 |
| Priority date | — |
| Expiry date | Aug 15, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/1076
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A RAID system includes an array of disk units, with data mapped on to the disks as a series of stripes, each containing data and parity chunks. The data chunks of each stripe are located on radially more outer parts of the disks and the parity chunks of each stripe are located on radially more inner parts of the disks. As a result, the amount of head movement for read operations is reduced, which improves the read performance. Successive chunks within each stripe are physically located at successively more radially inward positions on successive disks, so that each stripe has a helical configuration. Mirroring can be considered as a special case in which the number of data chunks is equal to the number of parity chunks, and the parity consists of a simple replication of the data. In this case, data is written to the outermost half of a first disk and to the innermost half of a second disk, and is read from the first disk.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.