COMPUTING SYSTEMS AND METHODS FOR MANAGING FLASH MEMORY DEVICE

• US 20100287327A1
• Filed: 02/15/2010
• Published: 11/11/2010
• Est. Priority Date: 05/06/2009
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Via Telecom Inc. (VIA Technologies)
• Inventors: Li, Rong, Wang, Huaqiao, Jin, Yuefeng
• Granted Patent: US 8,180,955 B2
• Time in Patent Office: Days
• US Class Current: 711/3
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7203 Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks

Abstract

A computing system is provided. A flash memory device includes at least one mapping block, at least one modification block and at least one cache block. A processor is configured to perform: receiving a write command with a write logical address and predetermined data, loading content of a cache page from the cache block corresponding to the modification block according to the write logical address to a random access memory device in response to that a page of the mapping block corresponding to the write logical address has been used, the processor, reading orderly the content of the cache page stored in the random access memory device to obtain location information of an empty page of the modification block, and writing the predetermined data to the empty page according to the location information. Each cache page includes data fields to store location information corresponding to the data has been written in the pages of the modification block in order.

Claims

1. A method for managing a flash memory device comprising at least one mapping block, at least one modification block and at least one cache block, the method comprising:

receiving a write command comprising a write logical address and predetermined data for writing the predetermined data in the flash memory device;

determining whether a page of the mapping block corresponding to the write logical address has been used; and

writing the predetermined data in an empty page of the modification block corresponding to the mapping block in response to that the page of the mapping block corresponding to the write logical address has been used, wherein the writing step further comprises;

loading content of a cache page of the cache block corresponding to the modification block according to the write logical address to a random access memory device;

reading orderly a plurality of data fields of the cache page in the random access memory device to obtain location information of the empty page of the modification block, wherein cache page of the cache block comprises the plurality of data fields to store the location information corresponding to the data which has been written in the pages of the modification block in order; and

writing the predetermined data in the empty page of the modification block according to the obtained location information.

2. The method as claimed in claim 1, further comprising:

writing location information of the page of the modification block storing the predetermined data in an empty page of the cache block.

3. The method as claimed in claim 1, further comprising:

obtaining a logical block number and a logical page number according to the write logical address; and

writing the logical page number in the cache block as location information of the page of the modification block storing the predetermined data.

4. The method as claimed in claim 3, further comprising:

allocating a data region and a redundant region in each cache page of the cache block, wherein the data region comprises the plurality of data fields to store the logical page number, and the redundant region stores a cache block index of the cache block and a physical block number of the modification block corresponding to the cache page of the cache block.

5. The method as claimed in claim 3, further comprising:

establishing a first table in the random access memory device for recording a mapping relationship between each logical block and each mapping block; and

establishing a second table in the random access memory device for recording status and link information of each physical block of the flash memory device.

6. The method as claimed in claim 5, further comprising:

storing a physical block number of the mapping block in the first table; and

storing a physical block number of the modification block corresponding to the mapping block and a cache block index of the cache block in the second table.

7. The method as claimed in claim 5, wherein the step of determining whether the page of the mapping block corresponding to the write logical address has been used further comprises:

looking the content up in the first table according to the logical block number to obtain the corresponding mapping relationship, and reading the page corresponding to the logical page number of the mapping block corresponding to the logical block number; and

reading information stored in a redundant region of the page to determine whether the page of the mapping block corresponding to the write logical address has been used.

8. The method as claimed in claim 5, wherein the step of loading the content of the cache page of the cache block corresponding to the modification block according to the write logical address to the random access memory device further comprises:

looking the content up in the second table according to a physical block number of the mapping block to obtain a physical block number of the modification block corresponding to the mapping block when the page of the mapping block has been used;

looking the content up in the second table according to the physical block number of the modification block to obtain a cache block index of the cache block corresponding to the modification block; and

looking the content up in a third table according to the cache block index to obtain information for loading content of the cache page of the cache block comprising information corresponding to non-empty pages of the modification block to the random access memory device,

wherein the third table stores the cache block index and a physical block number corresponding to the cache block and a page number of a first free cache page of the cache block.

9. The method as claimed in claim 1, wherein the location information of the empty page in the modification block corresponding to the write logical address is obtained by reading the data fields in a reversed order from the end of the cache page loaded in the random access memory device.

10. A method for managing a flash memory device comprising at least one mapping block, at least one modification block and at least one cache block, comprising:

receiving a read command comprising a read logical address for reading data from a page of the flash memory device;

determining whether data stored in a page of the mapping block corresponding to the read logical address has been modified; and

reading the predetermined data from the modification block corresponding to the mapping block in response to that the data stored in the page of the mapping block corresponding to the read logical address has been modified, wherein the reading step further comprises;

loading content of a cache page of the cache block corresponding to the modification block according to the read logical address to a random access memory device;

reading orderly a plurality of data fields of the cache page stored in the random access memory device to obtain location information of the page corresponding to the read logical address in the modification block, wherein cache page of the cache block comprises the plurality of data fields to store the location information corresponding to data which has been written in the pages of the modification block in order; and

reading the predetermined data from the page of the modification block according to the location information.

11. The method as claimed in claim 10, further comprising:

establishing a first table in the random access memory device for recording a mapping relationship between each logical block and each mapping block; and

establishing a second table in the random access memory device for recording a status and link information of each physical block.

12. The method as claimed in claim 11, further comprising:

storing a physical block number of each mapping block in the first table; and

storing a physical block number of each modification block and a cache block index of a cache block corresponding to each modification block in the second table.

13. The method as claimed in claim 11, wherein the step of determining whether the data stored in a page of the mapping block corresponding to the read logical address has been modified further comprises:

obtaining a logical block number and a logical page number according to the read logical address;

looking the content up in the first table according to the logical block number to obtain the physical block number of the mapping block corresponding to the logical block number; and

looking the content up in the second table according to the physical block number to determine whether the data stored in the page has been modified.

14. The method as claimed in claim 11, wherein the step of reading the predetermined data from the page of the modification block corresponding to the mapping block further comprises:

looking the content up in the second table according to the physical block number of the mapping block to obtain a physical block number of the modification block corresponding to the mapping block when the data stored in the page of the mapping block has been modified;

looking the content up in the second table according to the physical block number of the modification block to obtain a cache block index of the corresponding cache block; and

looking the content up in a third table according to the cache block index to obtain information for loading the content of the cache page of the cache block to the random access memory device,

wherein the third table stores the cache block index and a physical block number corresponding to the cache block and a page number of a first free cache page of the cache block.

15. The method as claimed in claim 14, further comprising:

allocating a data region and a redundant region in each cache page of the cache block, wherein the data region comprises a plurality of data fields to store the logical page number, and the redundant region stores the cache block index of the cache block and the physical block number of the modification block corresponding to the cache block.

16. The method as claimed in claim 14, further comprising:

reading the data fields in a reversed order from the end of the cache page loaded in the random access memory device to obtain the location information in the modification block of the page corresponding to the read logical address.

17. A computing system, comprising:

a flash memory device comprising at least one mapping block, at least one modification block and at least one cache block;

a random access memory device; and

a processor coupled to the flash memory device and the random access memory device, wherein the processor is configured to perform;

receiving a write command comprising a write logical address and predetermined data;

loading content of a cache page from the cache block corresponding to the modification block according to the write logical address to the random access memory device in response to that a page of the mapping block corresponding to the write logical address has been used;

reading orderly the content of the cache page stored in the random access memory device to obtain location information of an empty page of the modification block, and writing the predetermined data to the empty page according to the location information,

wherein each cache page of the cache block comprises a plurality of data fields to store location information corresponding to the data has been written in the pages of the modification block in order.

18. A computing system, comprising:

a flash memory device comprising at least one mapping block, at least one modification block and at least one cache block;

a random access memory device; and

a processor coupled to the flash memory device and the random access memory device, wherein the processor is configured to perform;

receiving a read command including a read logical address;

loading content of a cache page from the cache block corresponding to the modification block according to the read logical address to the random access memory device in response to tat a page of the mapping block corresponding to the read logical address has been modified;

reading orderly the content of the cache page stored in the random access memory device to obtain location information of a page corresponding to the read logical address in the modification block; and

reading predetermined data from the page of the modification block corresponding to the read logical address according to the location information,

wherein each cache page of the cache block comprises a plurality of data fields to orderly store the location information corresponding to data which has been written in the page of the modification block.

19. A method for managing a flash memory device comprising at least one mapping block, at least one modification block and at least one cache block, comprising:

receiving an access command comprising a logical address to access predetermined data in the flash memory device; and

accessing the modification block corresponding to the mapping block in response to that the mapping block corresponding to the logical address is determined not to be accessed for the predetermined data, wherein the step of accessing the modification block further comprises;

loading content of a cache page corresponding to the modification block from the cache block in the flash memory device to a random access memory device;

reading orderly the content of the cache page in the random access memory device to obtain location information for accessing the predetermined data in the modification block, wherein cache page of the cache block comprises a plurality of data fields to store the location information corresponding to the data which has been written in the pages of the modification block in order; and

accessing the predetermined data in the modification block of the flash memory device according to the location information.