DATA ACCESSING METHOD, AND STORAGE SYSTEM AND CONTROLLER USING THE SAME

• US 20100011151A1
• Filed: 09/15/2008
• Published: 01/14/2010
• Est. Priority Date: 07/09/2008
• Status: Active Grant

• Current Assignee: Phison Electronics Corporation
• Original Assignee: Phison Electronics Corporation
• Inventors: Yeh, Chih-Kang, Chu, Chien-Hua
• Granted Patent: US 8,176,267 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 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A data accessing method, and a storage system and a controller using the same are provided. The data accessing method is suitable for a flash memory storage system having a data perturbation module. The data accessing method includes receiving a read command from a host and obtaining a logical block to be read and a page to be read from the read command. The data accessing method also includes determining whether a physical block in a data area corresponding to the logical block to be read is a new block and transmitting a predetermined data to the host when the physical block corresponding to the logical block to be read is a new block. Thereby, the host is prevented from reading garbled code from the flash memory storage system having the data perturbation module.

Claims

1. A data accessing method, suitable for a flash memory storage device having a data perturbation module, wherein a flash memory of the flash memory storage device has a plurality of physical blocks, and the physical blocks are grouped into at least a data area and a spare area, the data accessing method comprising:

receiving a read command from a host, and obtaining a logical block to be read and a page to be read from the read command;

determining whether a physical block in the data area corresponding to the logical block to be read is a new block; and

transmitting a predetermined data to the host when the physical block corresponding to the logical block to be read is the new block.

2. The data accessing method according to claim 1, wherein the predetermined data is 0x00 or 0xFF.

3. The data accessing method according to claim 1, further comprising recording an indicator for each of the physical blocks to indicate that the physical block is the new block during a card activation process performed to the flash memory storage device, wherein the step for determining whether the physical block in the data area corresponding to the logical block to be read is the new block comprises:

determining whether the physical block in the data area corresponding to the logical block to be read is the new block according to the indicator, wherein the physical block in the data area corresponding to the logical block to be read is determined to be the new block if the physical block corresponding to the logical block to be read has the indicator.

4. The data accessing method according to claim 3, further comprising writing the predetermined data into a predetermined page of each of the physical blocks during the card activation process performed to the flash memory storage device, wherein the step for transmitting the predetermined data to the host when the physical block corresponding to the logical block to be read is the new block comprises reading data from the predetermined page of the physical block corresponding to the logical block to be read.

5. The data accessing method according to claim 4, wherein the predetermined page is a first page of the physical block.

6. The data accessing method according to claim 3, further comprising writing the predetermined data into all the pages of one of the physical blocks in the spare area during the card activation process performed to the flash memory storage device, wherein the step for transmitting the predetermined data to the host when the physical block corresponding to the logical block to be read is the new block comprises reading data from a page corresponding to the page to be read in the one of the physical blocks.

7. The data accessing method according to claim 3, wherein the step for transmitting the predetermined data to the host when the physical block corresponding to the logical block to be read is the new block comprises changing the data read from the physical block corresponding to the logical block to be read into the predetermined data by using a hardware or a firmware.

8. The data accessing method according to claim 1, further comprising decoding the data 0xFF in each of the physical blocks by using the data perturbation module and recording the decoded data 0xFF into a decode table during the card activation process performed to the flash memory storage device, wherein the step for determining whether the physical block in the data area corresponding to the logical block to be read is the new block comprises:

comparing the data read from the physical block corresponding to the logical block to be read with the data recorded in the decode table, wherein the physical block corresponding to the logical block to be read is determined to be the new block if the data read from the physical block corresponding to the logical block to be read is the same as the data recorded in the decode table.

9. The data accessing method according to claim 3, further comprising recording the indictor in a logical-physical mapping table.

10. The data accessing method according to claim 3, further comprising recording the indicator in a redundant area of each of the physical blocks.

11. A controller, suitable for a flash memory storage device having a flash memory, wherein the flash memory comprises a plurality of physical blocks, and the physical blocks are grouped into at least a data area and a spare area, the controller comprising:

a microprocessor unit, for obtaining a logical block to be read and a page to be read from a read command received from a host;

a data perturbation module, electrically connected to the microprocessor unit for decoding data read from the flash memory;

a flash memory interface, electrically connected to the microprocessor unit for accessing the flash memory;

a buffer memory, electrically connected to the microprocessor unit for temporarily storing data; and

a memory management module, electrically connected to the microprocessor unit for determining whether a physical block in the data area corresponding to the logical block to be read is a new block and transmitting a predetermined data to the host when the physical block corresponding to the logical block to be read is the new block.

12. The controller according to claim 11, wherein the predetermined data is 0x00 or 0xFF.

13. The controller according to claim 11, wherein the memory management module records an indicator for each of the physical blocks to indicate that the physical block is the new block during a card activation process performed to the flash memory storage device, and the memory management module determines whether the physical block in the data area corresponding to the logical block to be read is the new block according to the indicator.

14. The controller according to claim 13, wherein the memory management module writes the predetermined data into a predetermined page of each of the physical blocks during the card activation process, and the memory management module reads data from the predetermined page of the physical block corresponding to the logical block to be read when the physical block corresponding to the logical block to be read is the new block.

15. The controller according to claim 14, wherein the predetermined page is a first page of the physical block.

16. The controller according to claim 13, wherein the memory management module writes the predetermined data into all the pages of one of the physical blocks in the spare area during the card activation process, and the memory management module reads data from a page corresponding to the page to be read in the one of the physical blocks when the physical block corresponding to the logical block to be read is the new block.

17. The controller according to claim 13, wherein the memory management module changes the data read from the physical block corresponding to the logical block to be read into the predetermined data when the physical block corresponding to the logical block to be read is the new block.

18. The controller according to claim 11, wherein the memory management module decodes the data 0xFF in each of the physical blocks by using the data perturbation module and records the decoded data 0xFF into a decode table during the card activation process, and the memory management module determines the physical block corresponding to the logical block to be read to be the new block when the data read from the physical block corresponding to the logical block to be read is the same as the data recorded in the decode table.

19. The controller according to claim 13, wherein the memory management module records the indicator in a logical-physical mapping table.

20. The controller according to claim 13, wherein the memory management module records the indicator in a redundant area of each of the physical blocks.

21. The controller according to claim 11, wherein the flash memory storage device is a flash drive, a memory card, or a solid state drive (SSD).

22. A flash memory storage system, comprising:

a flash memory, for storing data, wherein the flash memory comprises a plurality of physical blocks, and the physical blocks are grouped into at least a data area and a spare area;

a connector, for connecting to a host; and

a controller, electrically connected to the flash memory and the connector, the controller obtaining a logical block to be read and a page to be read from a read command received from a host, determining whether a physical block in the data area corresponding to the logical block to be read is a new block, and transmitting a predetermined data to the host when the physical block corresponding to the logical block to be read is the new block,

wherein the controller has a data perturbation module for decoding data read from the flash memory.

23. The flash memory storage system according to claim 22, wherein the predetermined data is 0x00 or 0xFF.

24. The flash memory storage system according to claim 22, wherein the controller records an indictor for each of the physical blocks to indicate that the physical block is the new block during a card activation process, and the controller determines the physical block in the data area corresponding to the logical block to be read to be the new block according to the indicator.

25. The flash memory storage system according to claim 24, wherein the controller writes the predetermined data into a predetermined page of each of the physical blocks during the card activation process, and the controller reads data from the predetermined page of the physical block corresponding to the logical block to be read when the physical block corresponding to the logical block to be read is the new block.