Reassigning defective sectors on a disk
US5235585A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1991 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Sep 11, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention locates spare sectors for replacing secondary defects found during disk use. A sorted defective sector list is maintained for tracking the spare sectors that have been previously used for replacements of other secondary defects. When a secondary defect address is found, a secondary defect list is updated both on the disk and in the drive's memory. A spare sector, for replacing the secondary defect is located by first calculating a group number to determine which group the secondary defect is located in. Next, the boundaries for a plurality of spare sectors allocated for that group is determined. After searching the replacement sector list, the first available spare sector of the plurality of spare sectors is identified as the replacement sector. If all of the plurality of spare sectors have been previously assigned as replacement sectors, a spare sector is instead located from a plurality of spare sectors allocated to a neighboring group. After locating the spare sector, its physical address is returned and the spare sector is logged in the defective sector list and in the replacement list.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.