Hard disk drive employing a reference track to compensate for tracking error
Patent 4974109 Issued on November 27, 1990. Estimated Expiration Date: 
November 27, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 27, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References Re32075 3737883 3753254 3775655 3812533 3881184 3924268 Head positioning servo system for disk drives Thermal compensation for disk pack systems Positioning system and method particularly useful for magnetic disk drives InventorsAssigneeApplicationNo. 081651 filed on 08/04/1987US Classes:360/77.11, Continuous servo signal360/77.03, By nonmagnetic sensing (e.g., optical, capacitive)360/77.04, By memory storage of repeatable error or correction360/78.11Including nonmagnetic position sensingExaminersPrimary: Psitos, Aristotelis M.Assistant: Garland, Steven R. Attorney, Agent or FirmForeign Patent References
International ClassG11B 005/596Foreign Application Priority Data1986-08-27 JPAbstractA magnetic disc apparatus wherein off-track quantities are stored with regard to reference servo tracks formed circularly in divided data areas on a magnetic disc and, at the time of displacing the magnetic head, the head is shifted an extent of the stored off-track quantity after being once positioned by a head position detector. Gradients of the off-track quantities corresponding to tracks at individual temperatures in the apparatus are previously stored and, after the actual temperature is detected by means of a temperature sensor, the off-track quantity relative to the reference servo track is corrected in accordance with the gradient of the off-track quantity to the relevant track at the detected temperature, whereby just tracking is achieved. The magnetic head can be positioned exactly with respect to a desired data track while the head displacement time is shortened. Furthermore, data can be written in the entire length of each circular data track to enhance the efficiency of utilizing the magnetic disc, and high-precision tracking is attainable with the off-track quantity reduced to zero in any data track.Other References
Field of SearchRotary carrierBy nonmagnetic sensing (e.g., optical, capacitive) By memory storage of repeatable error or correction By tracking signal recorded on or immediately beneath surface Including nonmagnetic position sensing For rotary carrier (e.g., disc) Continuous servo signal Distinct servo sector By recorded servo reference or address signal Temperature compensation | |
