Write-through media caching

• US 9,311,939 B1
• Filed: 12/23/2014
• Issued: 04/12/2016
• Est. Priority Date: 12/23/2014
• 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: Malina, James N., Salehudin, Aznizam Abdullah, Tran, Bill Phuc
• Primary Examiner(s): Dinh, Tan X
• Application Number:
  US14/582,025
• Time in Patent Office: 476 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G11B 19/042 due to external shock or vibration
• CPC Class Codes: G11B 19/044 by using a data buffer
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1889 with discs

Abstract

Write-through media caching for a Data Storage Device (DSD) including at least one disk for storing data. A write command is received for storing data in the DSD and the data is written for the write command in a first region of the at least one disk with a first track density. The data for the write command is also written in a second region of the at least one disk with a second track density greater than the first track density without reading the data for the write command from the first region.

Claims

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

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

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

a controller configured to;

receive a write command for storing data in the DSD;

control the at least one head to write the data for the write command in the first region with a first track density using a first margin of allowable deviation from a center of a target track in the first region; and

control the at least one head to write the same data for the same write command in the second region with a second track density greater than the first track density using a second margin of allowable deviation from a center of a target track in the second region and without reading the data for the write command from the first region, wherein the second margin of allowable deviation is less than the first margin of allowable deviation.

2. The DSD of claim 1, wherein the first region and the second region include servo wedges for positioning the at least one head, and wherein the servo wedges are arranged in the first region so that they are read by the at least one head more frequently than the servo wedges in the second region during an operation of the at least one head.

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

determine whether there was an error in writing the data for the write command in the first region;

if there was an error in writing the data for the write command in the first region, control the at least one head to rewrite the data for the write command in the first region with the first track density; and

if there was not an error in writing the data for the write command in the first region, control the at least one head to write the data for the write command in the second region with the second track density.

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

determine whether there was an error in writing the data for the write command in the second region; and

if there was an error in writing the data for the write command in the second region, control the at least one head to rewrite the data for the command in the second region with the second track density.

5. The DSD of claim 1, further comprising a volatile memory for buffering the data for the write command, and wherein the controller is further configured to:

store the data for the write command in a write buffer of the volatile memory; and

control the at least one head to write the data for the write command in the first region and the second region using the data stored in the write buffer of the volatile memory.

6. The DSD of claim 5, wherein a data capacity size of the first region is approximately equal to a data capacity size for the write buffer of the volatile memory.

7. The DSD of claim 1, wherein the controller is further configured to control the at least one head to write the data for the write command in the second region in overlapping tracks.

8. The DSD of claim 7, wherein the controller is further configured to control the at least one head to write the data for the write command in the first region in overlapping tracks.

9. The DSD of claim 1, wherein a data capacity size of the first region is based on a predetermined amount of time for writing the data for the write command in the first region when writing the data for the write command in the second region would not be possible due to an environmental condition.

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

receive a plurality of write commands including the write command;

detect a sequentiality of the write commands; and

upon detection of the sequentiality of the write commands, perform the control of the at least one head to write the data for the write command in the first region with a first track density and the control of the at least one head to write the same data for the same write command in the second region with a second track density greater than the first track density and without reading the data for the write command from the first region.

11. A method for storing data in a Data Storage Device (DSD) including at least one disk with a first region and a second region, the method comprising:

receiving a write command for storing data in the DSD;

writing the data for the write command in the first region with a first track density using a first margin of allowable deviation from a center of a target track in the first region; and

writing the same data for the same write command in the second region with a second track density greater than the first track density using a second margin of allowable deviation from a center of a target track in the second region and without reading the data for the write command from the first region, wherein the second margin of allowable deviation is less than the first margin of allowable deviation.

12. The method of claim 11, wherein the first region and the second region include servo wedges for positioning at least one head of the DSD, and wherein the servo wedges are arranged in the first region so that they are read by the at least one head more frequently than the servo wedges in the second region during an operation of the at least one head.

13. The method of claim 11, further comprising:

determining whether there was an error in writing the data for the write command in the first region;

if there was an error in writing the data for the write command in the first region, rewriting the data for the write command in the first region with the first track density; and

if there was not an error in writing the data for the write command in the first region, writing the data for the write command in the second region with the second track density.

14. The method of claim 11, further comprising:

determining whether there was an error in writing the data for the write command in the second region; and

if there was an error in writing the data for the write command in the second region, rewriting the data for the command in the second region with the second track density.

15. The method of claim 11, wherein the DSD comprises a write buffer for buffering the data for the write command, and wherein the method further comprises:

storing the data for the write command in the write buffer; and

writing the data for the write command in the first region and the second region using the data stored in the write buffer.

16. The method of claim 15, wherein a data capacity size of the first region is approximately equal to a data capacity size for the write buffer.

17. The method of claim 11, further comprising writing the data for the write command in the second region in overlapping tracks.

18. The method of claim 17, further comprising writing the data for the write command in the first region in overlapping tracks.

19. The method of claim 11, wherein a data capacity size of the first region is based on a predetermined amount of time for writing the data for the write command in the first region when writing the data for the write command in the second region would not be possible due to an environmental condition.

20. The method of claim 11, further comprising:

receiving a plurality of write commands including the write command;

detecting a sequentiality of the write commands; and

upon detection of the sequentiality of the write commands, performing the controlling of the at least one head to write the data for the write command in the first region with a first track density and the controlling of the at least one head to write the same data for the same write command in the second region with a second track density greater than the first track density and without reading the data for the write command from the first region.

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

receive a write command for storing data in the DSD;

write the data for the write command in the first region with a first track density using a first margin of allowable deviation from a center of a target track in the first region; and

write the same data for the same write command in the second region with a second track density greater than the first track density using a second margin of allowable deviation from a center of a target track in the second region and without reading the data for the write command from the first region, wherein the second margin of allowable deviation is less than the first margin of allowable deviation.

22. The non-transitory computer readable medium of claim 21, wherein the computer-executable instructions further comprise computer-executable instructions to cause the controller to:

receive a plurality of write commands including the write command;

detect a sequentiality of the write commands; and

upon detection of the sequentiality of the write commands, perform the control of the at least one head to write the data for the write command in the first region with a first track density and the control of the at least one head to write the same data for the same write command in the second region with a second track density greater than the first track density and without reading the data for the write command from the first region.