Method of apparatus to characterize and limit the effect of disk damage in a hard disk drive
US6266199A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1999 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | May 18, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for monitoring the quality of the readback signal of data written on a magnetic recording disk in a disk drive and for limiting data loss due to physical damage at a slider/disk interface. The amplitude of a read signal is continuously monitored in the read channel, either by directly measuring the read signal amplitude or by monitoring the amplification level of the automatic gain control (AGC) circuit in the read channel which is inversely proportional to the read signal amplitude. If the amplitude of the monitored read signal decreases below a chosen level, the location of the data on the disk track is flagged as possibly damaged. The data is rewritten at the same location and then reread to see if full recovery of the degraded data is possible. If the amplitude read signal of the rewritten data is greater than a chosen level, the disk track is judged to be usable and normal operation continues. If the amplitude of the rewritten data read signal is less than the chosen level, permanent damage of the location on the data track is assumed and the data is rewritten at a new location on the magnetic recording disk.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.