Servo defect management scheme in hard disk drives
US6906883B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 2001 |
| Grant date | Jun 14, 2005 |
| Priority date | — |
| Expiry date | Oct 15, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B27/3027
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present disclosure relates to a system for detecting a plurality of defect types on the surface of a disk in a hard disk drive. In particular, the disclosure relates to utilizing information obtained from a plurality of servo bits to determine if a sector contains a physical defect. Where such a defect is found, the sector's write gate is disabled and its burst signal data is ignored for track following purposes. In addition, large changes in PES are used to identify closure spike defects. Such defects are managed by providing a compensation signal to the read value of the PES to improve track following. Finally, high PES values are used to signal a third defect type where no other signs of defect are present. In such case, the sector is mapped as defective, but the burst signals continue to be used for track following purposes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.