Preventive recovery from adjacent track interference

• US 7,747,907 B2
• Filed: 09/20/2005
• Issued: 06/29/2010
• Est. Priority Date: 09/20/2005
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Emo, Bruce Douglas, Coonen, Dan Joseph, Haines, Jonathan Williams, Feldman, Timothy Richard, Olds, Edwin Scott, Touchton, James Joseph
• Primary Examiner(s): Baderman; Scott T
• Assistant Examiner(s): PATEL, KAMINI B
• Application Number:
  US11/230,718
• Publication Number:
  US 20070074083A1
• Time in Patent Office: 1,743 Days
• Field of Search: 714/54, 714/5, 714/47, 714/42, 714/7, 360/60, 360/31, 711/112, 718/100
• US Class Current: 714/54
• CPC Class Codes: G06F 11/004 Error avoidance G06F11/07 and subgroups take precedence
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G11B 20/1883 Methods for assignment of alternate areas for defective areas
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers

Abstract

A predictive failure control circuit and associated method are provided in a data storing and retrieving apparatus. The circuit is configured to schedule a data integrity operation on data associated with a subportion of a data storage space, in relation to a comparison of an accumulated plurality of executed host access commands associated with the subportion. The subportion can comprise a sector or a single track or a band of tracks. A table preferably stores accumulated number of host access commands for each of a plurality of subportions of the data storage space. The data integrity operation can comprise reading the data on to detect degradation and restoring the recovered data to the same or to new, different tracks. The data subportions can also be reallocated to a new location.

Claims

1. A predictive failure control circuit apparatus that executes instructions stored on a computer readable medium to store ongoing observed numbers of executed host access commands individually for each of a plurality of different addressable storage locations of the medium, to compare each of the stored observed numbers to a predefined threshold quantity of executed host access commands, and in response to the comparison indicating that the stored observed number of executed host access commands at a first addressable storage location is greater than the predetermined threshold then to perform a data integrity operation on data stored at a second differently addressable storage location of the medium at a time when the stored observed number of executed host access commands at the second addressable storage location is less than the predetermined threshold quantity of executed host access commands.

2. The apparatus of claim 1 comprising a count table stored in the memory configured to store the observed numbers of executed host access commands.

3. The apparatus of claim 2 comprising a filtering table stored in memory configured to store a queue of other observed numbers of executed host access commands for each of a plurality of other addressable storage locations that are not represented in the count table but that are candidates for populating the count table in relation to ongoing host access command activity.

4. The apparatus of claim 1, wherein the first and second addressable storage locations are defined as different data storage tracks.

5. The apparatus of claim 4 wherein the data storage tracks are adjacent.

6. The apparatus of claim 5 wherein the data storage tracks overlap.

7. The apparatus of claim 1 wherein the first and second addressable storage locations are contained in a plurality of adjacent data storage tracks.

8. The apparatus of claim 7 wherein the plurality of data storage tracks are overlapping.

9. The apparatus of claim 1 wherein the observed number of executed host access commands at the first addressable location reflects a value summing the number of executed host access commands to any of a plurality of data storage tracks in a predefined band of data storage tracks, and the number of executed host access commands at the second addressable location reflects a value summing the number of executed host access commands to any of another different plurality of data storage tracks in another predefined band of data storage tracks.

10. The apparatus of claim 9 wherein the observed number of executed host access commands at one of the addressable storage locations reflects weighted incremental data associated with respective track locations of the executed host access commands within the respective band of data storage tracks.

11. The apparatus of claim 1 wherein the executed host access commands are characterized by storing data to the medium.

12. The apparatus of claim 1 wherein the data integrity operation is characterized by non-host commands to scan the medium in order to retrieve data.

13. The apparatus of claim 12 wherein the data integrity operation is characterized by reducing an effectiveness of an error correction scheme while scanning the medium.

14. The apparatus of claim 12 further configured to compare the observed number of executed host access commands to the threshold to implement a first data integrity operation that is non-interruptive of the ongoing host access command activity and to compare the observed number of executed host access commands to a second threshold to implement a second data integrity operation that interrupts the ongoing host access command activity.

15. A method comprising:

defining a subportion of a data storage space having a first addressable location and a second differently addressable location;

storing in a memory an ongoing observed number of executed host access commands at the first addressable location;

storing in the memory an ongoing observed number of executed host access commands at the second addressable location individually discernible from the observed number stored at the first addressable location;

comparing the observed numbers of executed host access commands at the first and second addressable locations individually to a predetermined threshold quantity of executed host access commands; and

in response to the comparing step, performing a data integrity operation on data stored at the second addressable location when the observed number of executed host access commands at the first addressable location is greater than the predefined threshold quantity of executed host access commands but the observed number of executed host access commands at the second addressable location is less than the predefined threshold quantity of executed host access commands.

16. The method of claim 15 wherein the defining step is characterized by the first and second addressable locations being different data storage tracks.

17. The method of claim 15 wherein the performing step is characterized by retrieving data from the second addressable location of the data storage space in response to storing data to the first addressable location of the data storage space.

18. The method of claim 15 wherein the defining step is characterized by the first and second addressable locations each being a band of a plurality of data storage tracks.

19. The method of claim 15 wherein the performing step is characterized by a first data integrity operation that is non-interruptive of ongoing host access command activity when the observed number of executed host access commands exceeds the threshold and a second data integrity operation that interrupts the ongoing host access command activity when the observed number of executed host access commands exceeds a second threshold.

20. An apparatus comprising:

a data transfer member responsive to host commands in a data storing and retrieving relationship with a storage medium; and

means for preventing adjacent storage location interference on the storage medium in relation to executed host access command activity individually at each of a plurality of addressable storage locations of the medium and a predetermined threshold quantity of executed host access commands.