System, method, and computer program product for reducing memory write operations using difference information

• US 7,904,619 B2
• Filed: 09/07/2007
• Issued: 03/08/2011
• Est. Priority Date: 11/24/2006
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: SandForce, Inc. (Broadcom, Inc.)
• Inventors: Danilak, Radoslav
• Primary Examiner(s): Song; Jasmine
• Application Number:
  US11/852,104
• Publication Number:
  US 20080126724A1
• Time in Patent Office: 1,278 Days
• Field of Search: 711/154, 711/162, 711/156, 710/52, 710/54, 710 56- 57
• US Class Current: 710/56
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• 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

Abstract

A system, method, and computer program product are provided for reducing write operations in memory. In use, write operations to be performed on data stored in memory are identified. A difference is then determined between results of the write operations and the data stored in the memory. Difference information associated with the difference is stored in the memory. To this end, the write operations may be reduced, utilizing the difference information.

Claims

1. A method, comprising:

receiving by an apparatus and from a host processor a command initiating an operation to be applied to storage devices;

identifying the operation as a write operation directed to one or more blocks of the storage devices;

computing difference information between data of the write operation and data of the one or more blocks;

appending the difference information to a coalescing buffer separate from the storage devices;

determining whether the coalescing buffer is full; and

based on the determining, writing the difference information in the coalescing buffer to the one or more blocks.

2. The method of claim 1, wherein the difference information is compressed.

3. The method of claim 1, wherein, in response to a read operation, the data of the one or more blocks and the difference information are retrieved, and the data of the write operation is reconstructed utilizing the difference information.

4. The method of claim 3, wherein the difference information is retrieved from the coalescing buffer.

5. The method of claim 1, wherein, in response to the coalescing buffer being full, the difference information is stored in the storage devices.

6. The method of claim 1, wherein the difference information is stored in a portion of the coalescing buffer having a predetermined size.

7. The method of claim 6, wherein the predetermined size is user configured.

8. The method of claim 6, wherein, in response to the difference information exceeding the predetermined size, the data of the one or more blocks and the difference information from the coalescing buffer are retrieved, the data of the write operation is reconstructed utilizing the difference information, and the reconstructed data is stored in the one or more blocks.

9. The method of claim 6, wherein the command is a first command, the operation is a first operation, the write operation is a first write operation, the difference information is first difference information, and further comprising:

receiving by the apparatus and from the host processor a second command initiating a second operation to be applied to the storage devices;

identifying the second operation as a second write operation directed to the one or more blocks of the storage devices;

computing second difference information based, at least in part, on the data of the second write operation; and

prior to the selectively writing, appending the second difference information to the portion of the coalescing buffer.

10. The method of claim 9, wherein the selectively writing the coalescing buffer to the storage devices selectively writes solely the portion of the coalescing buffer to the storage devices.

11. The method of claim 1, wherein the difference information is formatted into an instruction set having operation codes.

12. The method of claim 11, wherein the instruction set dynamically expands.

13. The method of claim 11, wherein the instruction set adaptively changes.

14. The method of claim 1, wherein the difference information is determined on a byte-by-byte basis.

15. The method of claim 14, wherein the storage devices include a disk drive.

16. The method of claim 1, wherein the difference information is determined utilizing motion estimation.

17. The method of claim 1, wherein the storage devices include a mechanical storage device.

18. The method of claim 1, wherein the storage devices include a volatile memory device.

19. The method of claim 1, wherein the storage devices include a nonvolatile memory device.

20. The method of claim 19, wherein the nonvolatile memory device includes at least one of single-bit per cell NOR flash memory, multi-bit per cell NOR flash memory, single-bit per cell NAND flash memory, and multi-bit per cell NAND flash memory.

21. The method of claim 1, further comprising:

after the selectively writing the coalescing buffer to the storage devices, emptying the coalescing buffer.

22. The method of claim 1, wherein the difference information includes data to be replaced in the one or more blocks.

23. The method of claim 22, further comprising:

compressing via a compression algorithm the difference information.

24. The method of claim 1, further comprising, prior to computing the difference information:

reading the one or more blocks from the storage devices; and

applying previous difference information already in the coalescing buffer to the data of the one or more blocks.

25. The method of claim 1, further comprising, prior to the selectively writing the coalescing buffer:

receiving by the apparatus and from the computer a second command to be applied to the storage devices;

identifying a second operation initiated by the second command as a read operation directed to the one or more blocks;

reading the one or more blocks from the storage devices;

applying the difference information from the coalescing buffer to the data of the one or more blocks to produce reconstructed data; and

returning the reconstructed data to the computer in response to the second operation.

26. A computer program product stored on a computer readable medium, wherein executed by a processor, the computer program product comprising:

computer code to receive by an apparatus and from a host processor a command initiating an operation to be applied to storage devices;

computer code to identify the operation as a write operation directed to one or more blocks of the storage devices;

computer code to compute difference information between data of the write operation and data of the one or more blocks;

computer code to append the difference information to a coalescing buffer separate from the storage devices;

computer code to determine whether the coalescing buffer is full; and

computer code to write the difference information in the coalescing buffer to the one or more blocks, based on the determination whether the coalescing buffer is full.

27. An apparatus, comprising:

a difference computation module enabled to receive from a host processor a command initiating an operation to be applied to storage devices, enabled to identify the operation as a write operation directed to one or more blocks of the storage devices, enabled to compute difference information between data of the write operation and data of the one or more blocks, enabled to append the difference information to a coalescing buffer separate from the storage devices, enabled to determine whether the coalescing buffer is full, and enabled to write the difference information in the coalescing buffer to the one or more blocks, based on the determination whether the coalescing buffer is full.

28. The apparatus of claim 27, wherein the apparatus is coupled between the host processor and the storage devices.

29. The apparatus of claim 27, wherein the apparatus is coupled between the host processor and secondary storage.