DATA PROTECTION METHOD FOR POWER FAILURE AND CONTROLLER USING THE SAME

• US 20090089484A1
• Filed: 01/16/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Phison Electronics Corporation
• Original Assignee: Phison Electronics Corporation
• Inventors: Chu, Chien-Hua
• Granted Patent: US 8,037,232 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers

Abstract

A data protection method suitable for a plurality of physical blocks mapped to a logical block in a non-volatile memory is provided. The data protection method includes recording data update information in each of the physical blocks for identifying an update relationship of the physical blocks and re-establishing the update relationship of the physical blocks according to the data update information. The data update information is composed of a plurality of words having a circular relationship, and the number of these words is greater than the number of the physical blocks. The data update information is sequentially recorded in each of the physical blocks according to the update relationship and the circular relationship.

Claims

1. A data protection method, suitable for a plurality of physical blocks mapped to a logical block in a non-volatile memory, the data protection method comprising:

recording a data update information in each of the physical blocks, wherein the data update information is used for identifying an update relationship of the physical blocks; and

re-establishing the update relationship of the physical blocks according to the data update information,

wherein the data update information comprises a plurality of words having a circular relationship, and the number of the words is greater than the number of the physical blocks,

wherein the data update information is sequentially recorded in each of the physical blocks according to the update relationship and the circular relationship.

2. The data protection method according to claim 1, wherein the words are a plurality of numbers or a plurality of characters.

3. The data protection method according to claim 1, wherein the step of re-establishing the update relationship comprises identifying a physical block containing the data update information of a word next to the unused words as the physical block having the oldest data according to the circular relationship and sequentially identifying the update relationship of the other physical blocks according to the circular relationship.

4. The data protection method according to claim 1, wherein the step of re-establishing the update relationship comprises identifying a physical block containing the data update information of a word next to the unused words as the physical block having the newest data according to the circular relationship and sequentially identifying the update relationship of the other physical blocks according to the circular relationship.

5. The data protection method according to claim 1, wherein the step of recording the data update information in each of the physical blocks is to record the data update information in a redundant area of the physical block.

6. The data protection method according to claim 1, wherein the non-volatile memory is a flash memory wherein each page can be programmed only once.

7. A controller, suitable for a storage device, wherein a logical block in a non-volatile memory of the storage device is mapped to a plurality of physical blocks, the controller comprising:

a non-volatile memory interface, for accessing the non-volatile memory;

a buffer memory, for storing data temporarily;

a microprocessor unit, for controlling the operation of the controller; and

a memory management module, for managing the non-volatile memory,

wherein the memory management module records a data update information in each of the physical blocks, and re-establishes the update relationship of the physical blocks according to the data update information, and

wherein the data update information is used for identifying an update relationship of the physical blocks, the data update information comprises a plurality of words having a circular relationship, and the number of the words is greater than the number of the physical blocks, and wherein the data update information is sequentially recorded in each of the physical blocks according to the update relationship and the circular relationship.

8. The controller according to claim 7, wherein the words are a plurality of numbers or a plurality of characters.

9. The controller according to claim 7, wherein in re-establishing the update relationship the memory management module identifies a physical block containing the data update information of a word next to the unused words as the physical block having the oldest data according to the circular relationship and sequentially identifies the update relationship of the other physical blocks according to the circular relationship.

10. The controller according to claim 7, wherein in re-establishing the update relationship the memory management module identifies a physical block containing the data update information of a word next to the unused words as the physical block having the newest data according to the circular relationship and sequentially identifies the update relationship of the other physical blocks according to the circular relationship.

11. The controller according to claim 7, wherein in recording the data update information in each of the physical blocks the memory management module records the data update information in a redundant area of the physical block.

12. The controller according to claim 7, wherein the non-volatile memory is a flash memory wherein each page can be programmed only once.

13. The controller according to claim 12, wherein the flash memory is a SLC NAND flash memory or a MLC NAND flash memory.

14. The controller according to claim 7, wherein the storage device is a flash memory storage medium, a USB flash drive, a flash memory card, or a solid state drive (SSD).

15. A data protection method, suitable for a plurality of physical blocks mapped to a logical block in a non-volatile memory, the data protection method comprising:

recording a data update information in each of the physical blocks, wherein the data update information is used for identifying an update relationship of the physical blocks; and

re-establishing the update relationship of the physical blocks according to the data update information,

wherein the data update information is recorded into each of the physical blocks while writing data into the physical block.

16. The data protection method according to claim 15, wherein the data update information can be recorded into the physical blocks only once.

17. The data protection method according to claim 16, wherein the data update information in the physical blocks comprises a plurality of circular words.

18. The data protection method according to claim 17, wherein the number of the circular words is between 3 and 5.

19. A controller, suitable for a storage device, wherein a logical block in a non-volatile memory of the storage device is mapped to a plurality of physical blocks, the controller comprising:

a non-volatile memory interface, for accessing the non-volatile memory;

a buffer memory, for storing data temporarily;

a microprocessor unit, for controlling the operation of the controller; and

a memory management module, for managing the non-volatile memory,

wherein the memory management module records a data update information in each of the physical blocks, and re-establishes the update relationship of the physical blocks according to the data update information

wherein the data update information is used for identifying an update relationship of the physical blocks, the data update information is recorded into each of the physical blocks while writing data into the physical block, and the data update information can be recorded into the physical blocks only once.

20. The controller according to claim 19, wherein the storage device is a flash memory storage medium, a USB flash drive, a flash memory card, or a SSD.