Servo control apparatus for a disk drive
US4630190A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1984 |
| Grant date | Dec 16, 1986 |
| Priority date | — |
| Expiry date | Feb 21, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/106
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a servo control apparatus for controlling a servo means that positions a recording head over a disk-shaped data storage medium. If the disk-shaped data storage medium is improperly mounted on a disk drive causing wobble of the disk as it turns, then the problem of runout occurs so that each of the tracks of data on the disk do not pass directly under the head throughout the whole rotation of the disk. The present invention provides a reference track near the outside circumference of the disk on which reference data is stored in a plurality of bursts spaced around the reference track. The servo control apparatus detects the reference data for each of the bursts and calculates the position of the centerline of the reference track with respect to the head for each of the bursts. From this calculation for 8 bursts spaced around the reference track, a computer means generates a runout factor which is used to control the servo means to position the head compensating for runout for each of the data tracks on the disk.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.