Method and apparatus for providing positional information on a disk

• US 7,158,337 B2
• Filed: 10/07/2005
• Issued: 01/02/2007
• Est. Priority Date: 09/13/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Chu, Sang Hoon, Choi, Soo Il, Nguyen, Tung, Shim, Jun Seok, Yu, Seong Hwan, Lee, Kang Seok
• Primary Examiner(s): TZENG, FRED
• Application Number:
  US11/245,644
• Publication Number:
  US 20060028755A1
• Time in Patent Office: 452 Days
• Field of Search: 360/77.08, 360/77.04, 360/63, 360/31, 360/75
• US Class Current: 360/77.08
• CPC Class Codes: G11B 5/5556 with track following after a "seek"
• CPC Class Codes: G11B 5/59644 Acquisition or selection of servo format from a system reference after track seek G11B5/5556

Abstract

The present invention is a method and apparatus for positioning a read/write head in a hard disk drive. The method comprises providing a disk having a at least one side with a plurality of tracks, where each of the tracks has a servo field with servo bits. The servo bits are read to provide a position signal for positioning a read/write head. The method determines a difference in position between an initial and a subsequent position of the read/write head on a track, where the subsequent location occurs after the read/write head has moved one revolution from the initial position on the track. The initial and subsequent positions are offset laterally. The method generates a compensation signal based on the initial position, the subsequent position and the difference. The position signal and the compensation signal are combined to provide a compensated position signal for positioning the read/write head. Various embodiments are described.

Claims

1. A hard disk drive, comprising:

a disk having at least one side with a plurality of tracks, each of said tracks having a servo field, said servo field having servo bits;

a head coupled to said disk;

an actuator arm assembly coupled to said head;

a voice coil motor coupled to said actuator arm;

a circuit that is coupled to said head and determines a magnitude of a difference in position between an initial position and a subsequent position of said head on a track, said subsequent location to occur after said head has moved one revolution from said initial position on said track, said initial and subsequent position being laterally offset, said circuit generates a compensation signal based on said initial position, said subsequent position and said difference with less than all of the sectors of a track, said circuit combines said position signal and said compensation signal to provide a compensated position signal for positioning said head.

2. The disk drive of claim 1, wherein said circuit determines a sector for initiating gap compensation based on said initial and subsequent positions.

3. The disk drive of claim 2, wherein circuit determines if a difference between said initial position and half of a length of said gap compensation is greater or equal to zero;

if so, said sector for initiating gap compensation is equal to a difference between said initial position and half of a length of said gap compensation;

otherwise, said sector for initiating gap compensation is equal to a sum of said difference between said initial position and half of a length of said gap compensation, and a total number of sectors on said track.

4. The disk drive of claim 3, wherein said compensation signal is further based on a current position of said head and said length of said gap compensation.

5. A hard disk drive, comprising:

a disk having at least one side with a plurality of tracks, each of said tracks having a servo field, said servo field having servo bits;

a head coupled to said disk;

an actuator arm assembly coupled to said head;

a voice coil motor coupled to said actuator arm;

circuit means for determining a magnitude of a difference in position between an initial position and a subsequent position of said head on a track, said subsequent location to occur after said head has moved one revolution from said initial position on said track, said initial and subsequent position being laterally offset, and for generating a compensation signal based on said initial position with less than all of the sectors of a track, said subsequent position and said difference, and for combining said position signal and said compensation signal to provide a compensated position signal for positioning said head.

6. The disk drive of claim 5, wherein said circuit determines a sector for initiating gap compensation based on said initial and subsequent positions.

7. The disk drive of claim 6, wherein circuit means determines if a difference between said initial position and half of a length of said gap compensation is greater or equal to zero;

if so, said sector for initiating gap compensation is equal to a difference between said initial position and half of a length of said gap compensation;

otherwise, said sector for initiating gap compensation is equal to a sum of said difference between said initial position and half of a length of said gap compensation, and a total number of sectors on said track.

8. The disk drive of claim 7, wherein said compensation signal is further based on a current position of said head and said length of said gap compensation.