Handling of verification data in disk drive cache

Patent metadata

Field	Value
Publication number	US-11422710-B2
Application number	US-202016994375-A
Country	US
Kind code	B2
Filing date	Aug 14, 2020
Priority date	Aug 14, 2020
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

In a magnetic recording drive that includes a shingled magnetic recording (SMR) region and a conventional magnetic recording (CMR) region, the quantity of validation data that is stored by the CMR region is reduced. In the magnetic recording drive, verification data stored in the CMR region is invalidated under certain circumstances, including when an SMR band is closed, when an SMR band is indicated by a host to be reused, when an SMR band is indicated to be finished, and when a last data track of an SMR has data stored therein.

First claim

We claim:

1. A disk drive comprising:
a shingled magnetic recording region that includes a plurality of data storage bands including a first data storage band including a first track to which a first set of data has been written;
a conventional magnetic recording region that includes a cache; and
a controller configured to:
upon receipt of a second set of data for storage from a host, determine whether an operating temperature of the disk drive is abnormal;
upon determining that the operating temperature is not abnormal, write the second set of data to a second track of the first data storage band that partially overlaps the first track; and upon determining that the operating temperature is abnormal,
write a first copy of the second set of data to the second track;
write a second copy of the second set of data to the cache;
verify the first set of data written to the first track; and
after verifying the first set of data, invalidate a copy of the first set of data from the cache.

2. The disk drive of claim 1 , wherein the controller is further configured to:
after verifying the first set of data, determine that the second track is the last track of the first data storage band; and
in response to determining that the second track is the last track of the first data storage band, verify the first copy of the second set of data written to the second track and invalidate the second copy of the second set of data from the cache.

3. The disk drive of claim 2 , wherein the controller is further configured to determine that the second track is the last track of the first data storage band when a write pointer for the first data storage band is positioned at an end point of the first data storage band.

4. The disk drive of claim 2 , wherein the second track is adjacent to the first track.

5. The disk drive of claim 1 , wherein
the second track is adjacent to the first track and overlaps the first track in the radial direction.

6. The disk drive of claim 5 , wherein the first set of data is partially overwritten in the radial direction by the second track.

7. The disk drive of claim 5 , wherein the controller is further configured to:
determine that a first portion of the first set of data cannot be verified and a second portion of the first set of data can be verified; and
retain in the cache a copy of the first portion of the first set of data and invalidate in the cache a copy of the second portion of the first set of data.

8. The disk drive of claim 7 , wherein the controller is configured to determine that the first portion of the first set of data cannot be verified and the second portion of the first set of data can be verified in response to the second track overwriting the first set of data.

9. The disk drive of claim 7 , wherein the controller is configured to determine that the first portion of the first set of data cannot be verified and the second portion of the first set of data can be verified in response to determining that the second track is the last track of the first data storage band.

10. The disk drive of claim 1 , wherein the controller is further configured to:
position a write pointer for the first data storage band at a start point of the first data storage band in response to receiving a command from a host; and
in response to positioning the write pointer at the start point, invalidate data stored in the cache that is associated with the first data storage band.

11. The disk drive of claim 1 , wherein the controller is further configured to:
after writing the first copy and the second copy of the second set of data, receive a command to close the first data storage band; and
verify the first copy in response to the command.

12. The disk drive of claim 11 , wherein all portions of the second track are not overwritten by any adjacent track of the first data storage band.

13. The disk drive of claim 11 , wherein the controller is further configured to, in response to the command:
determine that a particular portion of data stored in the first data storage band cannot be verified; and
in response to determining that the particular portion of data cannot be verified, retain a copy of the particular portion of data in the cache.

14. The disk drive of claim 11 , wherein the controller is further configured to, in response to the command:
determine that a particular portion of data stored the first data storage band is verified; and
in response to determining that the particular portion of data is verified, invalidate a copy of the particular portion of data in the cache.

15. The disk drive of claim 11 , wherein the controller is further configured to:
receive a command to open the first data storage band after receiving the command to close the first data storage band; and
in response to the command to open the first data storage band, copy to the cache data written to a third track of the first data storage band that has most recently had data appended thereto.

16. The disk drive of claim 15 , wherein the controller is further configured to:
write data to a fourth track of the first data storage band after copying to the cache the data written to the third track of the first data storage band, wherein the fourth track is adjacent to the third track and radially overlaps a portion of the third track; and
prior to writing the data to the fourth track, store a copy of data stored in the portion of the third track to the cache.

17. The disk drive of claim 16 , wherein the controller is further configured to:
after storing the copy of the data stored in the portion of the third track to the cache, verify the data stored in the portion of the third track; and
in response to verifying the data stored in the portion of the third track, invalidating in the cache the copy of the data stored in the portion of the third track.

18. The disk drive of claim 1 , wherein the controller is further configured to, upon determining that the operation temperature is abnormal and prior to writing the first copy of the second set of data to the second track, store the copy of the first set of data written to the first track in the cache.

19. The disk drive of claim 1 , wherein the first set of data written to the first track is verified using the copy of the first set of data stored in the cache.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Ehrlich Richard M
• Dunn Eric R
• Zayas Fernando A
• Aoki Shoichi

Classifications

• G06F3/0656

  Data buffering arrangements · CPC title

• G06F3/0676 Primary

  Magnetic disk device · CPC title

• G06F3/0653

  Monitoring storage devices or systems · CPC title

• G06F3/0659

  Command handling arrangements, e.g. command buffers, queues, command scheduling · CPC title

• G06F3/0616

  in relation to life time, e.g. increasing Mean Time Between Failures [MTBF] · CPC title