Dual reference track scheme
US4918972A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 1988 |
| Grant date | Apr 24, 1990 |
| Priority date | — |
| Expiry date | Nov 10, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/106
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for performing adaptive calibration of a disk drive assembly and for determining an offset value to compensate for differences in servo head to data head distance from a nominal value. The present invention has particular application in a relative track count servo system where absolute track position is not known from a reading of the servo track itself. In the preferred embodiment, a single head assembly having both a data head and a servo head is utilized. The distance between the data head center and the servo head center must be known so that a disk written on one drive assembly can be read in another drive assembly. This distance is a nominal value but may vary due to manufacturing tolerances. In the present invention, both the data and servo heads are utilized to establish a servo anchor reference track and to determine an offset correction value to compensate for variations in the servo/data head spacing. A dual reference track architecture is employed on the disk surface. The data head is positioned over the first reference track and centered to within a desired accuracy. Once the data head is in place, the servo track beneath the servo head is estab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.