FLASH MANAGEMENT USING SEPARATE MEDTADATA STORAGE

• US 20090259919A1
• Filed: 04/15/2009
• Published: 10/15/2009
• Est. Priority Date: 04/15/2008
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Ellis, Robert W., Kilzer, Kevin L., Sterbenz, Rudolph J.
• Granted Patent: US 8,185,778 B2
• Time in Patent Office: Days
• US Class Current: 714/773
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence

Abstract

Disclosed are techniques for flash memory management, including storing metadata and/or error correcting information separately from payload data. In various embodiments, metadata and/or error correcting information are stored in a random access memory within a solid state drive.

Claims

1. A method for flash memory management, comprising:

storing at least one of metadata or error correcting information, wherein the stored information is associated with one or more logical pages in a flash memory; and

constructing a data table associated with the flash memory, wherein entries of the data table correspond to logical pages within the flash memory, and wherein entries of the data table comprise at least one of metadata or error correcting information associated with the logical pages.

2. The method of claim 1, further comprising storing the data table entirely in a memory configured for random access.

3. The method of claim 1, wherein the data table is constructed responsive to the flash memory being powered on.

4. The method of claim 1, wherein entries of the data table correspond to logical pages within the flash memory, and wherein the size of the logical pages is smaller than the size of a physical page in the flash memory.

5. The method of claim 1, further comprising updating the data table responsive to payload data being stored in at least one logical page within the flash memory, wherein the payload data is written to the flash memory in the order it was received from a host.

6. The method of claim 5, wherein writing the payload data in the order it was received further comprises writing the payload data in a sequential manner within at least one erase block in the flash memory.

7. The method of claim 1, further comprising retrieving at least one of metadata or error correcting information without accessing the flash memory.

8. The method of claim 1, further comprising storing payload data in the flash memory, wherein the payload data is stored in memory elements in the flash memory intended to store at least one of metadata or error correcting information.

9. The method of claim 1, wherein storing at least one of metadata or error correcting information comprises storing, in an erase block in the flash memory, at least one of metadata or error correcting information associated with payload data stored in a different erase block in the flash memory.

10. The method of claim 1, wherein the flash memory comprises at least two flash memory chips having different storage capacities.

11. The method of claim 1, further comprising storing the data table on a flash chip in a solid state drive, wherein the flash chip is separately addressable from any portion of the flash memory used to store payload data.

12. The method of claim 1, further comprising storing the data table in its entirety in a first location, and storing a copy of the data table in its entirety in a second location.

13. The method of claim 12, wherein the first location is a first metadata storage memory within a solid state drive, and wherein the second location is a second metadata storage memory within the solid state drive.

14. The method of claim 13, wherein the first metadata storage memory and the second metadata storage memory are located on different integrated circuits.

15. A data storage system, comprising:

a first memory configured for block-based erase operations;

a controller in communication with the first memory, wherein the controller is configured to write incoming data to the first memory in the order the data is received;

a second memory configured for random access, wherein the second memory is in communication with the controller, wherein the second memory stores at least one of metadata or error correcting information, and wherein the stored information is associated with one or more logical pages in a flash memory.

16. The data storage system of claim 15, wherein the controller comprises a buffer-host machine, a media-buffer machine, a data buffer, a local buffer, and a sequence and control machine.

17. The data storage system of claim 15, wherein the controller is configured to write incoming payload data in a sequential manner within an erase block in the first memory.

18. The data storage system of claim 15, wherein the second memory contains a data table, wherein entries of the data table correspond to logical pages within the flash memory, and wherein entries of the data table comprise at least one of metadata or error correcting information associated with the logical pages.

19. The data storage system of claim 18, further comprising updating the data table responsive to payload data being stored in at least one logical page within the first memory, wherein the payload data is written to the first memory in the order it was received from a host.

20. A tangible computer-readable medium having instructions stored thereon, the instructions comprising:

instructions to store at least one of metadata or error correcting information, wherein the stored information is associated with one or more logical pages in a flash memory; and

instructions to construct a data table associated with the flash memory, wherein entries of the data table correspond to logical pages within the flash memory, and wherein entries of the data table comprise at least one of metadata or error correcting information associated with the logical pages.