Data Storage System and Method

• US 20110131365A1
• Filed: 08/03/2010
• Published: 06/02/2011
• Est. Priority Date: 11/30/2009
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Zhang, Bo, Chen, Liang, Chai, Honggang
• Granted Patent: US 8,706,989 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• 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 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages

Abstract

A data storage system and method are disclosed. The data storage system includes a first and a second memory and a memory control unit. The first memory is non-volatile, and the second memory is designed to store dynamic information of the first memory. The memory control unit includes a snapshot module, a recording module and a power-off recovery module, and is operative to handle the data loss of the second memory when an unexpected power-off occurs. When the power of the system is recovered, an initial address stored in the first memory by the snapshot module and link information and updating information recorded in the first memory by the recording module are obtained by the power-off recovery module to recovery the second memory.

Claims

1. A data storage system, comprising:

a first memory, being non-volatile and including a plurality of blocks;

a second memory, storing dynamic information of the first memory; and

a memory control unit coupled to the first and second memories, comprising;

a snapshot module, working during a snapshot interval, storing an initial address into the first memory, wherein the initial address indicates a starting block in the first memory that is allocated for a subsequent normal operation;

a recording module, working during a normal operation interval, recording updating information to free space of allocated blocks of the first memory, and recording link information between the allocated blocks, wherein the allocated blocks are the blocks altered during the normal operation interval; and

a power-off recovery module, working during a power-off recovery interval, utilizing the initial address that the snapshot module stored in the first memory and the link information and the updating information that the recording module recorded in the allocated blocks to recover the second memory so that it contains the dynamic information of the first memory without being affected by an unexpected power-off.

2. The system as claimed in claim 1, wherein the snapshot and the normal operation intervals happen alternatively.

3. The system as claimed in claim 1, wherein, based on the initial address and the link information, the power-off recovery module obtains the allocated blocks, and thereby combines the updating information recorded in the allocated blocks to recover the second memory.

4. The system as claimed in claim 1, wherein, during the snapshot interval, the snapshot module further updates the dynamic information stored in the second memory to the first memory.

5. The system as claimed in claim 1, wherein the dynamic information includes a logical-to-physical address mapping table, and the updating information includes logical addresses.

6. The system as claimed in claim 5, wherein each block of the first memory is further divided into a plurality of pages, and each page corresponds to one of said logical addresses.

7. The system as claimed in claim 1, wherein the link information between a first and a second block of the allocated blocks includes a physical address of the second block, and the second block is allocated subsequently to the first block.

8. The system as claimed in claim 7, wherein each block of the first memory is further divided into a plurality of pages and the physical address of the second block is recorded in a free space of one arbitrary page of the first block.

9. The system as claimed in claim 1, wherein the snapshot interval happens every predetermined time period, or happens every time a predetermined amount of data is stored to the first memory.

10. The system as claimed in claim 1, wherein the first memory is a NAND flash.

11. The system as claimed in claim 1, wherein the second memory is a random access memory.

12. A data storage method, comprising:

providing a first memory for data storage, wherein the first memory is non-volatile and includes a plurality of blocks;

providing a second memory to store dynamic information of the first memory;

storing an initial address into the first memory during a snapshot interval, wherein the initial address indicates a starting block in the first memory, the starting block is allocated for a subsequent normal operation;

recording updating information to free space of allocated blocks of the first memory, and recording link information between the allocated blocks, wherein the allocated blocks are the blocks altered during a normal operation interval, and the recording of the updating information and the link information is performed during the normal operation interval;

wherein when an unexpected power-off occurs, utlizing the initial address stored during the snapshot interval and the updating information and the link information recorded during the normal operation interval to recover the dynamic information stored in the second memory.

13. The method as claimed in claim 12, wherein the snapshot and normal operation intervals happen alternatively.

14. The method as claimed in claim 12, wherein the steps executed to recover the dynamic information stored in the second memory further comprise:

obtaining the allocated blocks according to the initial address and the link information, and combining the updating information stored in the allocated blocks to recover the dynamic information stored in the second memory.

15. The method as claimed in claim 12, wherein the dynamic information includes a logical-to-physical address mapping table, and the updating information includes logical addresses.

16. The method as claimed in claim 15, wherein each block of the first memory is further divided into a plurality of pages, and each page corresponds to one of said logical addresses, and the step of recording the updating information during the normal operation interval includes:

recording the logical addresses of the pages of the allocated blocks to the corresponding pages.

17. The method as claimed in claim 12, wherein the step of recording the link information between the allocated blocks includes:

allocating a second block for subsequent normal operations when a first block is being used; and

recording a physical address of the second block as the link information and storing the link information to a free space of the first block,

wherein the first block and the second block are of the allocated blocks.

18. The method as claimed in claim 17, wherein the steps performed to recover the dynamic information stored in the second memory further comprise:

determining that the second block is the most recent allocated block of the allocated blocks when no link information is obtained from the second block.

19. The method as claimed in claim 12, wherein the steps performed during the snapshot interval further comprises:

updating the dynamic information stored in the second memory to the first memory.

20. The method as claimed in claim 12, wherein the snapshot interval happens every predetermined time period, or the snapshot interval happens every time a predetermined amount of data is stored to the first memory.