Dynamically assigning inactive pages not used in Reed-Solomon code in non-volatile solid-state storage array

• US 9,026,893 B1
• Filed: 12/13/2012
• Issued: 05/05/2015
• Est. Priority Date: 12/13/2012
• 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: Syu, Mei-Man L., Pajaro, Cliff
• Primary Examiner(s): Blair, April Y
• Assistant Examiner(s): GANDHI, DIPAKKUMAR B
• Application Number:
  US13/713,561
• Time in Patent Office: 873 Days
• US Class Current: 714/784
• CPC Class Codes: G06F 11/1044 with specific ECC/EDC distribution
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 2212/7208 Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes

Abstract

A data storage device is disclosed comprising non-volatile solid-state array comprising M storage elements for storing data protected by Reed-Solomon (R-S) code, each storage element comprising multiple blocks, each block comprising multiple pages for storing data. The data storage device further comprises a controller in communication with the storage array and defining a superblock comprising logical grouping of M blocks, each located in different storage element, and multiple superpages in each superblock, each superpage comprising M pages, each located in a different storage element. The controller generates, for each superpage, at least one R-S code parity page for protecting data pages in the superpage, where number of data pages and the at least one parity page is equal to M−1. The controller assigns one page in each superpage as an inactive page not used in the R-S code, where at least two inactive pages are in different storage elements.

Claims

1. A data storage device comprising:

a non-volatile solid-state storage array comprising M storage elements for storing data protected by a Reed-Solomon code, each storage element comprising a plurality of blocks, and each block comprising a plurality of pages for storing data;

a controller in communication with the non-volatile solid-state storage array and operable to;

define a superblock comprising a logical grouping of M blocks, wherein each block in the superblock is located in a different storage element, wherein each superblock comprises a plurality of superpages, wherein each superpage comprises a logical grouping of M pages, and wherein each page in a superpage is in a different storage element;

generate, for each superpage, at least one Reed-Solomon code parity page protecting data pages in the superpage, wherein the number of data pages and the at least one parity page is equal to M−

1; and

assign one page in each superpage as an inactive page not used in the Reed-Solomon code, wherein at least two of the inactive pages are in different storage elements.

2. The data storage device as recited in claim 1, wherein the controller is further operable to move the inactive page in at least one superpage from a first location in a first storage element to a second location in a second storage element.

3. The data storage device as recited in claim 2, wherein the controller is operable to move the inactive page in at least one superpage during a wear leveling operation.

4. The data storage device as recited in claim 2, wherein the controller is operable to move the inactive page in at least one superpage during a garbage collection operation.

5. The data storage device as recited in claim 2, wherein the controller is operable to move the inactive page in at least one superpage during an error handling operation.

6. The data storage device as recited in claim 1, wherein the controller is further operable to track the location of the inactive page in each superpage.

7. The data storage device as recited in claim 6, wherein the controller is operable to track the location of the inactive page in each superpage by using a tracking table.

8. The data storage device as recited in claim 1, wherein the controller is operable to assign a defective page in a superpage as the inactive page.

9. The data storage device as recited in claim 1, wherein the controller is operable to assign a page having a quality level below a threshold in a superpage as the inactive page.

10. The data storage device as recited in claim 1, wherein at least two inactive pages in at least two superpages in a superblock are in different storage elements.

11. The data storage device as recited in claim 1, wherein all of the inactive pages in all of the superpages in a superblock are in the same storage element.

12. The data storage device as recited in claim 1, wherein the storage element comprises a die.

13. The data storage device as recited in claim 1, wherein the storage element comprises a plane, and wherein at least two planes are located in one die.

14. The data storage device as recited in claim 1, wherein M is equal to 256.

15. The data storage device as recited in claim 1, wherein the Reed-Solomon code comprises 8-bit symbols.

16. The data storage device as recited in claim 1, further comprising magnetic media for storing data.

17. The data storage device as recited in claim 1, wherein the inactive page is assigned in each and every superpage within the super block.

18. The data storage device as recited in claim 1, wherein the inactive page is dynamically assigned to each superpage regardless of whether a defect occurs in the superpage.

19. A method of operating a data storage device, the data storage device comprising a non-volatile storage array comprising M storage elements for storing data protected by a Reed-Solomon code, each storage element comprising a plurality of blocks, and each block comprising a plurality of pages for storing data, the method comprising:

defining a superblock comprising a logical grouping of M blocks, wherein each block in the superblock is located in a different storage element, wherein each superblock comprises a logical grouping of M pages, and wherein each page in a superpage is in a different storage element;

generating, for each superpage, at least one Reed-Solomon code parity page protecting data pages in the superpage, wherein the number of data pages and the at least one parity page is equal to M−

1; and

assigning one page in each superpage as an inactive page not used in the Reed-Solomon code, wherein at least two of the inactive pages are in different storage elements.

20. The method as recited in claim 19, further comprising moving the inactive page in at least one superpage from a first location in a first storage element to a second location in a second storage element.

21. The method as recited in claim 20, wherein the inactive page in at least one superpage is moved during a wear leveling operation.

22. The method as recited in claim 20, wherein the inactive page in at least one superpage is moved during a garbage collection operation.

23. The method as recited in claim 20, wherein the inactive page in at least one superpage is moved during an error handling operation.

24. The method as recited in claim 19, further comprising tracking the location of the inactive page in each superpage.

25. The method as recited in claim 24, wherein tracking the location of the inactive page in each superpage comprises using a tracking table.

26. The method as recited in claim 19, further comprising assigning a defective page in a superpage as the inactive page.

27. The method as recited in claim 19, further comprising assigning a page having a quality level below a threshold in a superpage as the inactive page.

28. The method as recited in claim 19, wherein at least two inactive pages in at least two superpages in a superblock are in different storage elements.

29. The method as recited in claim 19, wherein all of the inactive pages in all of the superpages in a superblock are in the same storage element.

30. The method as recited in claim 19, wherein the storage element comprises a die.

31. The method as recited in claim 19, wherein the storage element comprises a plane, and wherein at least two planes are located in one die.

32. The method as recited in claim 19, wherein M is equal to 256.

33. The method as recited in claim 19, wherein the Reed-Solomon code comprises 8-bit symbols.

34. The method as recited in claim 19, wherein the data storage device further comprises magnetic media for storage data.