Spiral servo patterns with absolute reference point
US7561359B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2004 |
| Grant date | Jul 14, 2009 |
| Priority date | — |
| Expiry date | Jul 23, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59661
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is directed to a method and apparatus for providing an absolute reference point on a disk surface of a disk drive. A write head associated with the disk surface is used to write spirals of servo information thereon, for example, under control of a servo track writer. The spirals of servo information include standard spirals and special spirals. In one embodiment, the special spirals are shorter than the standard spirals and the special spirals are rotationally non-symmetric. For example, an unequal number of standard spirals are interposed between one pair of adjacent special spirals relative to the number of standard spirals interposed between other pairs of adjacent special spirals. The special spirals may take a variety of other forms to distinguish themselves from standard spirals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.