Page-based failure management for flash memory

• US 8,122,319 B2
• Filed: 01/24/2007
• Issued: 02/21/2012
• Est. Priority Date: 01/24/2007
• Status: Active Grant

• Current Assignee: Thstyme International Limited
• Original Assignee: Charles I. Peddle
• Inventors: Peddle, Charles I.
• Primary Examiner(s): Rizk, Sam
• Application Number:
  US11/657,935
• Publication Number:
  US 20080177956A1
• Time in Patent Office: 1,854 Days
• Field of Search: 714/763, 365/185.22
• US Class Current: 714/763
• CPC Class Codes: G11C 29/88 with partially good memories

Abstract

A page-based failure management system for flash memory includes at least one flash memory device which includes at least one page and at least one operable page. The system also includes an indication of operability of the at least one page in the at least one flash device.

Claims

1. A page-based failure management system for flash memory, comprising:

at least one flash memory device, said at least one flash memory device comprising a plurality of blocks, each of said blocks comprising a plurality of pages; and

a memory controller for executing read, write and erase commands for said at least one flash memory device;

wherein said memory controller has at least one indication of an inoperable page in said flash memory device, said memory controller using other operable pages in a same block that contains an inoperable page.

2. The system of claim 1, wherein said at least one indication is stored in said at least one flash memory device.

3. The system of claim 1, wherein at least one operable page is identified from said indication identifying said at least one inoperable page.

4. The system of claim 3, wherein said at least one indication is determined prior to operation on said at least one operable page.

5. The system of claim 1, wherein at least one page further comprises a plurality of sectors and said at least one indication further identifies the operability of at least one operable sector individually in said at least one page.

6. The system of claim 1, wherein said memory controller is further configured to determine the operability of individual pages during operation of said flash memory device and update said at least one indication of an inoperable page.

7. The system of claim 1, wherein said memory controller is further configured to determine at least one change in operability of said at least one page.

8. The system of claim 7, wherein said memory controller is further configured to update said at least one indication to indicate said at least one change in operability of said at least one page.

9. The system of claim 7, wherein said change in operability is determined concurrently with operation on at least one operable page.

10. The system of claim 1, wherein said at least one flash memory device comprises at least one NAND flash memory device.

11. The system of claim 1, wherein said memory controller and said at least one flash memory device are configured to separate and reattach.

12. The system of claim 1, wherein said at least one indication comprises a table of operable pages within each block.

13. The system of claim 1, wherein said at least one indication comprises a table of inoperable pages within each block.

14. The system of claim 1, further comprising an error and checking correction (ECC) module for detecting pages that fail during operation of said flash memory device and for updating said at least one indication of an inoperable page in said flash memory device.

15. A method of page-based failure management for flash memory, comprising:

in a flash memory device comprising a plurality of blocks, each of said blocks comprising a plurality of pages,

storing at least one indication of the operability of at least one said page in said flash memory device; and

operating on at least one page, indicated to be operable by said at least one indication, that is located in a same block as another page indicated to be inoperable by said at least one indication.

16. The method of claim 15, further comprising determining the operability of at least one of said pages, wherein said determining step and said operating step are performed concurrently.

17. The method of claim 15, further comprising updating said at least one indication to reflect a change in operability of said at least one page.

18. The method of claim 15, wherein said indication identifies an operable page.

19. The method of claim 15, wherein said indication identifies at least one inoperable page.

20. The method of claim 15, wherein each page comprises a plurality of sectors, said method comprising tracking operability of individual sectors and using operable sectors even if one or more sectors within a same page are inoperable.