Seek control method for a disk device used for reading/writing data from and to a disk recording medium

• US 6,295,254 B1
• Filed: 04/29/1999
• Issued: 09/25/2001
• Est. Priority Date: 05/21/1998
• Status: Expired due to Term

• Current Assignee: Ts-Optics Corporation
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Tomishima, Yuichiro
• Primary Examiner(s): Tran, Thang V.
• Application Number:
  US09/302,031
• Time in Patent Office: 880 Days
• Field of Search: 369/44.28, 369/32, 369/54, 369/44.29, 369/44.27, 369/44.34, 369/58, 369/44.35, 369/53.29, 369/53.28, 360/78.04, 360/78.05
• US Class Current: 369/44.28
• CPC Class Codes: G11B 7/08529 Methods and circuits to control the velocity of the head as it traverses the tracks
• CPC Class Codes: G11B 7/08541 involving track counting to determine position

Abstract

A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk is provided. The method includes the steps of counting mirror signals generated for every revolution of the disk recording medium, where each mirror signal corresponds to one of the tracks radially arranged on the disk recording medium; moving a pickup until the counted number of mirror signals is equal to a predetermined number of tracks required for the pickup to pass to reach a target track. The method further includes the steps of checking respective intervals of successive mirror signals; determining if there is a difference in length between intervals of two successive mirror signals; and executing a correction mode by adding or subtracting a correction value to the counted number of mirror signals if there is a difference in length between intervals of two successive mirror signals.

Claims

1. A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk, said method comprising the steps of:

(a) moving the pickup of the disk device towards a target track of the disk;

(b) counting the number of mirror signals detected during movement of the pickup, where each mirror signal is associated with a respective track radially arranged on the disk;

(c) determining if movement of the pickup has been completed by comparing the counted number of mirror signals to a predetermined number of tracks required to reach the target track and stopping the movement of the pickup if the counted number of mirror signals equals the predetermined number of tracks;

(d) determining a respective interval length for each mirror signal if the counted number of mirror signals does not equal the predetermined number of tracks;

(e) comparing the respective interval lengths of two successive mirror signals to determine if there is a difference in interval length; and

(f) correcting the counted number of mirror signals by adding or subtracting a correction value to the counted number of mirror signals if there is a difference in interval length between the two successive mirror signals.

2. The method according to claim 1, wherein the step of comparing comprises the steps of:

(e1) dividing the tracks of the disk into an acceleration region, a maximum speed region, and a deceleration region, where in the acceleration region an interval length for a mirror signal associated with a preceding track is greater than an interval length for a mirror signal associated with a present track, in the maximum speed region the interval length for the mirror signal associated with the preceding track is equal to the interval length for the mirror signal associated with the present track, and in the deceleration region the interval length for the mirror signal associated with the preceding track is less than the interval length for the mirror signal associated with the present track;

(e2) returning to step (b) if all conditions identified in step (e1) are satisfied;

(e3) determining if a focus error has occurred;

(e4) stopping the movement of the pickup if a focus error has occurred;

(e5) determining if a mirror signal interval associated with a track succeeding the present track has been counted within a predetermined time period;

(e6) stopping the movement of the pickup if the mirror signal interval associated with the track succeeding the present track has not been counted within the predetermined time period; and

(e7) proceeding to step (f) if the mirror signal interval associated with the track succeeding the present track has been counted within the predetermined time period.

3. The method according to claim 1, wherein the step of correcting comprises the steps of:

(f1) dividing a mirror signal interval associated with a present track by a mirror signal interval associated with a preceding track to obtain a quotient; and

(f2) adding the quotient to a current counted number of mirror signals.

4. The method according to claim 2, wherein predetermined time periods corresponding to the acceleration, the maximum speed, and the deceleration regions, respectively, are stored within a processing unit.

5. The method according to claim 1, wherein the step of counting is performed by a system control unit.

6. The method according to claim 1, further comprising the step of returning to step (b) after the step of correcting.

7. A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk, said method comprising the steps of:

(a) moving the pickup of the disk device towards a target track of the disk;

(b) counting the number of mirror signals detected during movement of the pickup, where each mirror signal is associated with a respective track radially arranged on the disk;

(c) determining if movement of the pickup has been completed by comparing the counted number of mirror signals to a predetermined number of tracks required to reach the target track and stopping the movement of the pickup if the counted number of mirror signals equals the predetermined number of tracks;

(d) checking respective interval lengths of successive mirror signals;

(e) determining whether said successive mirror signal interval lengths satisfy a predetermined relationship;

(f) returning to step (b) if said predetermined relationship is satisfied;

(g) determining whether an interval length of a mirror signal associated with a succeeding track of said successive mirror signals has been counted within a predetermined time if said successive mirror signal interval lengths do not satisfy said predetermined relationship;

(h) executing a correction mode if said interval length of the mirror signal associated with the succeeding track has been counted within said predetermined time; and

(i) executing a forced stop mode for said pickup if said interval length of the mirror signal associated with the succeeding track has not been counted within said predetermined time.

8. The method according to claim 7, wherein the step of executing further comprises the step of returning to step (b) if the executing step is satisfied.

9. The method according to claim 7, wherein said predetermined relationship is defined by dividing the tracks of the disk into an acceleration region, a maximum speed region, and a deceleration region, where in the acceleration region an interval length for a mirror signal associated with a preceding track is greater than an interval length for a mirror signal associated with a present track, in the maximum speed region the interval length for the mirror signal associated with the preceding track is equal to the interval length for the mirror signal associated with the present track, and in the deceleration region the interval length for the mirror signal associated with the preceding track is less than the interval length for the mirror signal associated with the present track.

10. A method for performing a seek control operation for a disk device of the type having a pickup for reading/writing data from and to a disk, said method comprising the steps of:

(a) moving the pickup of the disk device towards a target track of the disk;

(b) counting the number of mirror signals detected during movement of the pickup, where each mirror signal is associated with a respective track radially arranged on the disk;

(c) determining if movement of the pickup has been completed by comparing the counted number of mirror signals to a predetermined number of tracks required to reach the target track and stopping the movement of the pickup when the counted number of mirror signals equals the predetermined number of tracks; and

(d) checking respective interval lengths of successive mirror signals when the counted number of mirror signals does not equal to the predetermined number of tracks thereby to execute a force to stop the pickup if there is a difference between the interval lengths.

11. The method according to claim 10, wherein said successive mirror signals are two.