METHOD FOR OPERATING NON-VOLATILE MEMORY AND DATA STORAGE SYSTEM USING THE SAME

• US 20100174852A1
• Filed: 05/03/2009
• Published: 07/08/2010
• Est. Priority Date: 01/07/2009
• Status: Active Grant

• Current Assignee: Silicon Motion Incorporated California (Silicon Motion)
• Original Assignee: Silicon Motion Incorporated California (Silicon Motion)
• Inventors: CHIEN, Jieh-Hsin, Chang, Hsiao-Te
• Granted Patent: US 8,291,152 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7211 Wear leveling
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 16/3495 Circuits or methods to detect or delay wearout of nonvolatile EPROM or EEPROM memory devices, e.g. by counting numbers of erase or reprogram cycles, by using multiple memory areas serially or cyclically
• CPC Class Codes: G11C 29/24 Accessing extra cells, e.g. dummy cells or redundant cells
• CPC Class Codes: G11C 29/44 Indication or identification of errors, e.g. for repair
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• CPC Class Codes: G11C 29/70 Masking faults in memories by using spares or by reconfiguring
• CPC Class Codes: G11C 29/72 with optimized replacement algorithms

Abstract

A method for operating a non-volatile memory is provided. The non-volatile memory includes a plurality of physical blocks haing a plurality of data blocks and spare blocks. An index is obtained by comparing an average erase count of selected physical blocks with a first threshold. Each erase count for each physical block is the total number of the erase operations performed thereon. A performance capability status for the memory is determined according to the index. The performance capability status is set to a first status when the average erase count exceeds the first threshold. An indication is generated based on the performance capability status. A limp function is performed in response to the first status for configuring a minimum number of the at least some spare blocks reserved and used for data update operations.

Claims

1. A method for operating a non-volatile memory having a plurality of physical blocks, which comprise a plurality of data blocks and a plurality of spare blocks, wherein the data blocks are used for storing data, and at least some spare blocks corresponding to the data blocks are reserved and used for data update operations, comprising:

obtaining an index by comparing an average erase count of selected physical blocks with a first threshold;

determining a performance capability status for the non-volatile memory according to the index, wherein the performance capability status is set to a first status when the average erase count exceeds the first threshold;

generating an indication based on the performance capability status; and

performing a limp function in response to the first status, wherein the limp function is used to configure a minimum number of the at least some spare blocks reserved and used for data update operations.

2. The method according to claim 1, wherein when the average erase count is below the first threshold, the index is obtained by comparing the average erase count with a second threshold.

3. The method according to claim 2, wherein the indication is displayed by two flashing light signals alternating between a yellow color and a green color based on the compared result of the average erase count and the second threshold.

4. The method according to claim 1, wherein the index is obtained by comparing the average erase count with the first threshold and comparing a third threshold with a total number of spare blocks other than the at least some spare blocks corresponding to the data blocks reserved and used for data update operations.

5. A method for operating a non-volatile memory having a plurality of physical blocks, which comprise a plurality of data blocks and a plurality of spare blocks, wherein the data blocks are used for storing data, and at least some spare blocks corresponding to the data blocks are reserved and used for data update operations, comprising:

generating an index according to a total number of spare blocks other than the at least some spare blocks corresponding to the data blocks reserved and used for data update operations;

displaying an indication according to the index; and

performing a limp function when the indication is in a first status, wherein the limp function is used to configure a minimum number of the at least some spare blocks reserved and used for data update operations.

6. The method according to claim 5, wherein the index is further generated according to an average erase count of selected physical blocks.

7. The method according to claim 6, wherein the average erase count of selected physical blocks is larger than a first threshold.

8. The method according to claim 5, wherein the total number of spare blocks is less than a spare threshold.

9. The method according to claim 5, wherein the indication is displayed by a flashing light signal of a red color in response to the first status.

10. The method according to claim 5, further comprising:

performing a backup operation on the non-volatile memory in response to the first status for backup user data.

11. A data storage system, comprising:

a memory module having a non-volatile memory and a controller, wherein the non-volatile memory comprises a plurality of physical blocks having a plurality of data blocks and a plurality of spare blocks, and the data blocks are used for storing data and at least some spare blocks corresponding to the data blocks are reserved and used for data update operations, and the controller coupled to the non-volatile memory for obtaining an average erase count of selected physical blocks, wherein each erase count for each physical block is the total number of the erase operations performed thereon; and

a host coupled to the memory module for obtaining an index by comparing the average erase count with a first threshold, determining a performance capability status for the non-volatile memory according to the index, wherein the performance capability status is set to a first status when the average erase count exceeds the first threshold, generating an indication based on the performance capability status and performing a limp function in response to the first status, wherein the limp function is to configure a minimum number of the at least some spare blocks reserved and used for data update operations.

12. The data storage system according to claim 11, further comprising:

a monitor coupled to the host for displaying the indication.

13. The data storage system according to claim 11, wherein when the average erase count is below the first threshold, the host obtains the index by comparing the average erase count with a second threshold.

14. The data storage system according to claim 13, wherein the indication is displayed by two flashing light signals alternating between a yellow color and a green color based on the compared result of the average erase count and the second threshold.

15. The data storage system according to claim 11, wherein the host obtains the index by comparing the average erase count with the first threshold and comparing a third threshold with a total number of spare blocks other than the at least some spare blocks corresponding to the data blocks reserved and used for data update operations.

16. The method according to claim 11, wherein the host obtains the index by comparing each erase count of the selected physical blocks with the first threshold and comparing a third threshold with a total number of spare blocks other than the at least some spare blocks corresponding to the data blocks reserved and used for data update operations.

17. The data storage system according to claim 16, wherein the performance capability status is set to the first status when each erase count of the selected physical blocks exceeds the first threshold and when the total number is less than the third threshold.

18. The data storage system according to claim 17, wherein the indication is displayed by a flashing light signal of a red color in response to the first status.

19. The data storage system according to claim 18, wherein in response to the first status, the host instructs the controller to perform a backup operation on the non-volatile memory.