IP Library Granted Patent US 8,154,812
Granted Patent B1
US 8,154,812 · App. 13/253,294 · Granted Apr 10, 2012

Condensing a defect scan log for a disk of a disk drive

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Quick Facts
Patent No.
US 8,154,812
App. No.
13/253,294
Granted
Apr 10, 2012
Kind
B1
Abstract

The embodiments relate to optimizing a defect log of a storage device, such as a disk drive. The defect log may comprise entries for individual locations, such as sectors on a disk, and entries indicating zones. A zone comprises a plurality of locations in the medium of the storage device and may contain adjacent or non-adjacent defects. One or more medium of the storage device may be scanned for defects and locations of these defects are recorded in the defect log. The defect log may then be analyzed to determine if certain number of defects are in proximity to each other, adjacent or non-adjacent, within a zone. If the defects within a zone exceed a threshold, then the defect log may be condensed by coalescing the individual entries of the defects into zone entries. In addition, the defect log may be further condensed by coalescing zone entries of adjacent zones into combined entries.

Claims (35)

1. A method for optimizing a defect log for a medium of a storage device, wherein the defect log comprises entries indicating individual locations in the medium of the storage and zone entries indicating zones comprising a plurality of locations in the medium of the storage device, the method comprising:

detecting defects in locations in the medium of the storage device;

recording the locations of the defects into respective entries for individual locations in the defect log;

determining a quantity of defects that are adjacent or non-adjacent within a first zone of locations based on the entries of detected defects;

recording a zone entry in the defect log for the first zone of locations when the quantity of defects within the first zone exceed a threshold; and

removing the respective entries of the defects from the defect log that are within the zone entry for the first zone.

2. The method of claim 1 , wherein the zone entries indicating a zone comprise a first parameter indicating a plurality of wedges and a second parameter indicating a plurality of tracks.

3. The method of claim 1 , wherein recording the zone entry for the first zone of locations when the quantity of defects within the first zone exceed a threshold comprises recording the zone entry for the first zone of locations when the quantity of defects within the first zone exceed a threshold when the size of the defect log exceeds a threshold size.

4. The method of claim 1 , further comprising:

determining when zones recorded in the defect log are adjacent to one another based on their respective zone entries; and

combining the zone entries of adjacent zones into a single zone entry encompassing the adjacent zones.

5. The method of claim 4 , further comprising determining that the size of the defect log exceed a second threshold size prior to determining that the number of defects detected in adjacent zones and combining the zone entries of the adjacent zones.

6. The method of claim 4 , wherein the sizes of the adjacent zones are approximately equal.

7. The method of claim 1 , wherein the defect log is condensed prior to use of the storage device with a host device.

8. The method of claim 7 , further comprising determining if a number of sectors identified in the defect log exceeds a threshold value.

9. A disk drive comprising:

a disk including a plurality of tracks of sectors having a plurality of wedges;

a head to perform read operations from the disk including reading defects on the disk; and

a processor for controlling operations in the disk drive to condense a defect log for the disk, wherein the defect log comprises entries indicating defects located in individual sectors in the disk and zone entries indicating zones comprising at least a plurality of tracks and wedges, the operations comprising:

detecting defects in sectors in the disk of the disk drive,

recording the locations of the defects into respective entries for individual sectors in the defect log,

determining a quantity of defects that are adjacent or non-adjacent within a first zone based on the entries of detected defects,

recording a zone entry in the defect log for the first zone when the quantity of defects within the first zone exceed a threshold, and

removing the respective entries of the defects from the defect log that are within the zone entry for the first zone.

10. The disk drive of claim 9 , wherein the zone entry comprises adjacent and non-adjacent defects detected on the disk that are in proximity to one another along a first axis corresponding to a circumferential direction for the plurality of wedges and a second axis corresponding to a radial direction for the plurality of tracks.

11. The disk drive of claim 9 , wherein the processor performs operations further comprising determining that the number of log entries exceed a second threshold prior to recording a zone entry in the defect log for the first zone when the quantity of defects within the first zone exceed a threshold, and removing the respective entries of the defects from the defect log that are within the zone entry for the first zone.

12. The disk drive of claim 9 , wherein the processor performs operations further comprising:

determining that the number of defects detected in a second zone exceed the first threshold;

recording a second zone entry for the second zone;

determining that the first and second zones are adjacent to one another based on the zone entry and second zone entry; and

combining the zone entry and second zone entry into a single zone entry that encompasses at least the first and second zones.

13. The disk drive of claim 12 , wherein the processor performs operations further comprising determining that the number of log entries exceed a second threshold prior to determining that the first and second zones are adjacent to one another based on the zone entry and second zone entry and combining the zone entry and second zone entry into a single zone entry that encompasses at least the first and second zones.

14. The disk drive of claim 12 , wherein the sizes of the first and second zones are approximately equal size.

15. The disk drive of claim 9 , wherein the defect log is condensed prior to use of the disk drive with a host device.

16. The disk drive of claim 15 , wherein the processor performs operations further comprising determining if a number of sectors identified in the defect log exceed a threshold value.

Assignments (5)
RELEASE OF SECURITY INTEREST AT REEL 038744 FRAME 0481 Recorded Feb 8, 2022
From: JPMORGAN CHASE BANK, N.A.
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 058982/0556 →
RELEASE OF SECURITY INTEREST Recorded Mar 5, 2018
From: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
To: WESTERN DIGITAL TECHNOLOGIES, INC.
Reel/Frame 045501/0714 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 038722/0229 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: U.S. BANK NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 038744/0281 →
SECURITY AGREEMENT Recorded May 17, 2016
From: WESTERN DIGITAL TECHNOLOGIES, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 038744/0481 →