Reducing effects of wide area track erasure in a disk drive

• US 8,699,159 B1
• Filed: 06/18/2012
• Issued: 04/15/2014
• Est. Priority Date: 06/18/2012
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Malina, James N.
• Primary Examiner(s): HINDI, NABIL Z
• Application Number:
  US13/525,611
• Time in Patent Office: 666 Days
• Field of Search: 360/31, 360/53, 360/54, 360/55, 360/39, 369/30.21, 369/57.17, 369/53.15
• US Class Current: 360/31
• CPC Class Codes: G11B 20/10305 signal quality assessment
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence

Abstract

Apparatus and methods for managing data stored in a disk drive having at least one disk including a first zone of tracks for storing data and a second zone of tracks for storing data, with the second zone being adjacent the first zone. It is determined whether a write counter for the first zone exceeds a threshold value. The write counter for the first zone represents a number of times the first zone has been completely written with data. If it is determined that the write counter for the first zone exceeds the threshold value, the disk drive is controlled to rewrite data from at least a portion of the second zone.

Claims

1. A disk drive, comprising:

at least one disk including a plurality of tracks for storing data, wherein the plurality of tracks are divided into a plurality of zones including at least a first zone of tracks and a second zone of tracks adjacent the first zone;

a read element constructed to read data stored in the plurality of tracks;

a write element constructed to write data in the plurality of tracks;

a memory storing a plurality of write counters for the plurality of zones, with each write counter representing a number of times a zone of the plurality of zones has been completely written by the write element; and

a controller configured to;

retrieve a write counter for the first zone from the memory;

determine whether the write counter for the first zone exceeds a threshold value during a zone monitoring process, the zone monitoring process being performed to determine whether any of the plurality of write counters stored in the memory exceed the threshold value;

control the read element to read data stored in at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value; and

control the write element to rewrite the data read by the read element from the second zone if it is determined that the write counter for the first zone exceeds the threshold value.

2. The disk drive of claim 1, wherein the controller is further configured to determine whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.

3. The disk drive of claim 2, wherein the controller is further configured to:

control the write element to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and

increment the write counter for the first zone after the write element has written data in the first zone in accordance with the request to write data in the first zone.

4. The disk drive of claim 1, wherein the controller is further configured to control the write element to rewrite the data read by the read element from the second zone in a zone associated with a lowest write counter of the plurality of write counters stored in the memory.

5. The disk drive of claim 1, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the controller is further configured to:

control the read element to read data stored in at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value; and

control the write element to rewrite the data read by the read element from the third zone if it is determined that the write counter for the first zone exceeds the threshold value.

6. The disk drive of claim 1, wherein the controller is further configured to:

disable writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

reset the write counter for the first zone after the rewritten data of the second zone has been rewritten.

7. The disk drive of claim 5, wherein the controller is further configured to:

disable writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

reset the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.

8. A method for managing data stored in a disk drive having at least one disk including a plurality of zones including at least a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, the method comprising:

determining whether a write counter for the first zone exceeds a threshold value during a zone monitoring process to determine whether any write counters of a plurality of write counters for the plurality of zones exceed the threshold value, with each write counter representing a number of times a zone of the plurality of zones has been completely written with data; and

controlling the disk drive to rewrite data from at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value.

9. The method of claim 8, further comprising determining whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.

10. The method of claim 9, further comprising:

controlling the disk drive to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and

incrementing the write counter for the first zone after data has been written in the first zone in accordance with the request to write data in the first zone.

11. The method of claim 8, wherein controlling the disk drive to rewrite data written in at least a portion of the second zone includes rewriting the data from the second zone in a zone associated with a lowest write counter of the plurality of write counters.

12. The method of claim 8, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the method further comprises controlling the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.

13. The method of claim 8, further comprising:

disabling writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

resetting the write counter for the first zone after the rewritten data of the second zone has been rewritten.

14. The method of claim 12, further comprising:

disabling writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

resetting the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.

15. A non-transitory computer readable medium storing computer-executable instructions for managing data stored in a disk drive having at least one disk including a plurality of zones including at least a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, and wherein when the computer-executable instructions are executed by a controller or a processor, the computer-executable instructions cause the controller or processor to:

determine whether a write counter for the first zone exceeds a threshold value during a zone monitoring process for determining whether any write counters of a plurality of write counters for the plurality of zones exceed the threshold value, with each write counter representing a number of times a zone of the plurality of zones has been completely written with data; and

control the disk drive to rewrite data from at least a portion of the second zone if it is determined that the write counter for the first zone exceeds the threshold value.

16. The non-transitory computer readable medium of claim 15, wherein the computer-executable instructions further cause the controller or the processor to determine whether the write counter for the first zone exceeds the threshold value is made in response to a request to write data in the first zone.

17. The non-transitory computer readable medium of claim 15, wherein the at least one disk includes a third zone of tracks adjacent the first zone on a side opposite the second zone, and wherein the computer-executable instructions further cause the controller or the processor to control the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.

18. A disk drive, comprising:

at least one disk including a plurality of tracks for storing data, wherein the plurality of tracks are divided into at least a first zone of tracks and a second zone of tracks adjacent the first zone;

a read element constructed to read data stored in the plurality of tracks;

a write element constructed to write data in the plurality of tracks;

a memory storing a write counter for the first zone, wherein the write counter represents a number of times the first zone has been completely written with data by the write element; and

a controller configured to;

retrieve the write counter for the first zone from the memory;

determine whether the write counter for the first zone exceeds a threshold value; and

if it is determined that the write counter for the first zone exceeds the threshold value;

control the read element to read data stored in at least a portion of the second zone;

control the write element to rewrite the data read by the read element from the second zone;

disable writing in the first zone until after the rewritten data of the second zone has been rewritten; and

reset the write counter for the first zone after the rewritten data of the second zone has been rewritten.

19. The disk drive of claim 18, wherein the controller determines whether the write counter for the first zone exceeds the threshold value in response to a request to write data in the first zone.

20. The disk drive of claim 19, wherein the controller is further configured to:

control the write element to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and

increment the write counter for the first zone after the write element has written data in the first zone in accordance with the request to write data in the first zone.

21. The disk drive of claim 18, wherein the memory stores a plurality of write counters for a plurality of zones of tracks, with each write counter representing a number of times a zone of the plurality of zones has been completely written by the write element, and wherein the controller is further configured to control the write element to rewrite the data read by the read element from the second zone in a zone associated with a lowest write counter of the plurality of write counters stored in the memory.

22. The disk drive of claim 18, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the controller is further configured to:

control the read element to read data stored in at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value; and

control the write element to rewrite the data read by the read element from the third zone if it is determined that the write counter for the first zone exceeds the threshold value.

23. The disk drive of claim 22, wherein the controller is further configured to:

disable writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

reset the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.

24. A method for managing data stored in a disk drive having at least one disk including a first zone of tracks for storing data and a second zone of tracks for storing data, wherein the second zone is adjacent the first zone, the method comprising:

determining whether a write counter for the first zone exceeds a threshold value, wherein the write counter for the first zone represents a number of times the first zone has been completely written with data; and

if it is determined that the write counter for the first zone exceeds the threshold value;

controlling the disk drive to rewrite data from at least a portion of the second zone;

disabling writing in the first zone until after the rewritten data of the second zone has been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

resetting the write counter for the first zone after the rewritten data of the second zone has been rewritten.

25. The method of claim 24, wherein the determination of whether the write counter for the first zone exceeds the threshold value is made in response to a request to write data in the first zone.

26. The method of claim 25, further comprising:

controlling the disk drive to write data in accordance with the request to write data in the first zone if it is determined that the write counter for the first zone does not exceed the threshold value; and

incrementing the write counter for the first zone after data has been written in the first zone in accordance with the request to write data in the first zone.

27. The method of claim 24, wherein controlling the disk drive to rewrite data written in at least a portion of the second zone includes rewriting the data from the second zone in a zone associated with a lowest write counter of a plurality of write counters for a plurality of zones of tracks with each write counter representing a number of times a zone of the plurality of zones has been completely written.

28. The method of claim 24, wherein the at least one disk includes a third zone of tracks adjacent the first zone and on a side of the first zone opposite the second zone, and wherein the method further comprises controlling the disk drive to rewrite data from at least a portion of the third zone if it is determined that the write counter for the first zone exceeds the threshold value.

29. The method of claim 28, further comprising:

disabling writing in the first zone until after the rewritten data of the second and third zones have been rewritten if it is determined that the write counter for the first zone exceeds the threshold value; and

resetting the write counter for the first zone after the rewritten data of the second and third zones have been rewritten.