Data management for data storage device with different track density regions

• US 9,129,628 B1
• Filed: 10/23/2014
• Issued: 09/08/2015
• Est. Priority Date: 10/23/2014
• 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: Boyle, William B., Fallone, Robert M.
• Primary Examiner(s): Neyzari, Ali
• Application Number:
  US14/522,451
• Time in Patent Office: 320 Days
• Field of Search: 360/15, 360/51, 360/46, 360/77.08
• US Class Current: 1/1
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10212 compensation for data shift, e.g. pulse-crowding effects
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1889 with discs
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/09 Digital recording
• CPC Class Codes: G11B 5/5521 across disk tracks spiral track following G11B5/596
• CPC Class Codes: G11B 5/5526 Control therefor; circuits, track configurations or relative disposition of servo-information transducers and servo-information tracks for control thereof G11B5/556 takes precedence
• CPC Class Codes: G11B 5/596 for track following on disks G11B5/5526, G11B5/5552, G11B5/5565, G11B5/5582 take precedence

Abstract

Managing data stored in a Data Storage Device (DSD) including at least one disk for storing data. Data is written in a first region of the at least one disk with a first track density. A frequency of access is determined for the data written in the first region, and the frequency of access is compared to a threshold. Based on the comparison, a copy of the data written in the first region is written in a second region of the at least one disk with a second track density different than the first track density.

Claims

1. A Data Storage Device (DSD), comprising:

at least one disk for storing data including a first region and a second region;

at least one head for reading and writing data on the at least one disk; and

a controller configured to;

control the at least one head to write data in the first region with a first track density;

determine a frequency of access for the data written in the first region;

compare the frequency of access for the data written in the first region to a threshold; and

based on the comparison, control the at least one head to write a copy of the data written in the first region in the second region with a second track density different than the first track density.

2. The DSD of claim 1, wherein the frequency of access is based on a number of previous read commands to access the data.

3. The DSD of claim 1, wherein the frequency of access is based on a number of previous write commands to modify the data.

4. The DSD of claim 1, wherein the frequency of access is based on information provided from a host in communication with the DSD.

5. The DSD of claim 1, wherein the controller is further configured to:

determine whether the frequency of access for the data written in the first region is less than the threshold; and

if the frequency of access is less than the threshold, control the at least one head to write a copy of the data written in the first region in the second region with the second track density, wherein the second track density is greater than the first track density.

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

determine whether the frequency of access for the data written in the first region is greater than or equal to the threshold; and

if the frequency of access is greater than or equal to the threshold, control the at least one head to write a copy of the data written in the first region in the second region with the second track density, wherein the second track density is less than the first track density.

7. The DSD of claim 1, wherein the controller is further configured to adjust the threshold based on a remaining available data capacity of the first region.

8. The DSD of claim 1, wherein the second track density is greater than the first track density, and wherein the controller is further configured to perform an Inter-Track Interference Cancellation (ITIC) operation for data stored in the second region without performing the ITIC operation for data stored in the first region, and in performing the ITIC operation, the controller is further configured to:

control the at least one head to read data from a target track in the second region;

control the at least one head to read data from an adjacent track in the second region that is adjacent the target track; and

account for an effect of the data in the adjacent track on the data in the target track.

9. The DSD of claim 1, wherein the second track density is greater than the first track density, and wherein the controller is further configured to perform a refresh operation for data stored in the second region without performing the refresh operation for data stored in the first region, and in performing the refresh operation, the controller is further configured to:

identify data in the second region that is susceptible to interference from an adjacent track; and

control the at least one head to rewrite the data that is susceptible to interference from the adjacent track on the at least one disk.

10. The DSD of claim 1, wherein the first track density is lower than the second track density and the first region is located in a middle diameter portion of the at least one disk.

11. The DSD of claim 1, wherein the controller is further configured to:

determine an updated frequency of access for data written in the second region that is no longer stored in the first region;

compare the updated frequency of access to the threshold; and

based on the comparison, control the at least one head to write a copy of the data stored in the second region in the first region with the first track density.

12. A method for managing data stored in a Data Storage Device (DSD) including at least one disk for storing data, the method comprising:

writing data in a first region of the at least one disk with a first track density;

determining a frequency of access for the data written in the first region;

comparing the frequency of access for the data written in the first region to a threshold; and

based on the comparison, writing a copy of the data written in the first region in a second region of the at least one disk with a second track density different than the first track density.

13. The method of claim 12, wherein the frequency of access is based on a number of previous read commands to access the data.

14. The method of claim 12, wherein the frequency of access is based on a number of previous write commands to modify the data.

15. The method of claim 12, wherein the frequency of access is based on information provided from a host in communication with the DSD.

16. The method of claim 12, further comprising:

determining whether the frequency of access for the data written in the first region is less than the threshold; and

if the frequency of access is less than the threshold, writing a copy of the data written in the first region in the second region with the second track density, wherein the second track density is greater than the first track density.

17. The method of claim 12, further comprising:

determining whether the frequency of access for the data written in the first region is greater than or equal to the threshold; and

if the frequency of access is greater than or equal to the threshold, writing a copy of the data written in the first region in the second region with the second track density, wherein the second track density is less than the first track density.

18. The method of claim 12, further comprising adjusting the threshold based on a remaining available data capacity of the first region.

19. The method of claim 12, wherein the second track density is greater than the first track density, and wherein the method further comprises performing an Inter-Track Interference Cancellation (ITIC) operation for data stored in the second region without performing the ITIC operation for data stored in the first region, and in performing the ITIC operation, the method further comprises:

reading data from a target track in the second region;

reading data from an adjacent track in the second region that is adjacent the target track; and

accounting for an effect of the data in the adjacent track on the data in the target track.

20. The method of claim 12, wherein the second track density is greater than the first track density, and wherein the method further comprises performing a refresh operation for data stored in the second region more frequently than for data stored in the first region, and in performing the refresh operation, the method further comprises:

identifying data that is susceptible to interference from an adjacent track; and

rewriting the data that is susceptible to interference from the adjacent track on the at least one disk.

21. The method of claim 12, wherein the first track density is lower than the second track density and the first region is located in a middle diameter portion of the at least one disk.

22. The method of claim 12, further comprising:

determining an updated frequency of access for data written in the second region that is no longer stored in the first region;

comparing the updated frequency of access to the threshold; and

based on the comparison, writing a copy of the data stored in the second region in the first region with the first track density.

23. A non-transitory computer readable medium storing computer-executable instructions for managing data stored in a Data Storage Device (DSD) including at least one disk for storing data, wherein when the computer-executable instructions are executed by a controller, the computer-executable instructions cause the controller to:

write data in a first region of the at least one disk with a first track density;

determine a frequency of access for the data written in the first region;

compare the frequency of access for the data written in the first region to a threshold; and

based on the comparison, write a copy of the data written in the first region in a second region of the at least one disk with a second track density different than the first track density.

24. A host in communication with a Data Storage Device (DSD), the host comprising:

an interface for communicating with the DSD; and

a processor configured to;

store data in a first region of at least one disk of the DSD with a first track density;

determine a frequency of access for the data stored in the first region;

compare the frequency of access for the data stored in the first region to a threshold; and

based on the comparison, store a copy of the data written in the first region in a second region of the at least one disk with a second track density different than the first track density.