Data storage in nonvolatile memory

• US 8,656,091 B2
• Filed: 07/25/2011
• Issued: 02/18/2014
• Est. Priority Date: 07/25/2011
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Smith, Kenneth Kay, Snyder, Adam J, Butler, David G
• Primary Examiner(s): Doan, Duc
• Application Number:
  US13/190,122
• Publication Number:
  US 20130031304A1
• Time in Patent Office: 939 Days
• Field of Search: None
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/401 Compressed data
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers

Abstract

A method for data storage in a nonvolatile memory device includes compressing current data. The compressed current data is written to a space of the nonvolatile memory device that does not include a most recently written data. If the compressed current data is successfully written, identification data is stored on the nonvolatile memory device. The identification data identifies the written compressed current data as a currently valid version.

Claims

1. A method for data storage in a nonvolatile memory device, the method comprising:

compressing update data into second compressed update data, the update data representing an updated version of first data, the first data stored in a compressed format as first compressed data in a first space of the nonvolatile memory device, and the first compressed data indicated as a valid version by identification data stored in a header in the nonvolatile memory device;

writing the second compressed update data to a second space of the nonvolatile memory device that does not include a most recently written data; and

only when the second compressed update data is successfully written, updating the identification data in the header to identify the second compressed update data in the second space as the valid version.

2. The method of claim 1, wherein writing the second compressed update data comprises calculating a checksum, and wherein successful writing of the second compressed update data is indicated by a valid value of the checksum.

3. The method of claim 1, wherein a field of the header stores the corresponding identification data, the header being stored in a dedicated space of the nonvolatile memory device, the header to identify currently valid versions of data stored in the nonvolatile memory device.

4. The method of claim 1, further comprising, prior to compressing the update data, (1) identifying frequently updated data from among the update data, (2) extracting the frequently updated data from the update data, and (3) writing the identified frequently updated data in uncompressed form to a frequently updated data block of the nonvolatile memory device.

5. The method of claim 1, further comprising:

when the second compressed update data is not successfully written, repeating the writing of the second compressed update data, and

when the second compressed update data is successfully written after repeating the writing, updating the identification data.

6. The method of claim 1, further comprising:

determining a first size of free space in the nonvolatile memory device; and

when a second size of the compressed update data is greater than the first size of the free space, overwriting previously stored data in the non-volatile memory device, wherein the previously stored data does not include the most recently stored data.

7. The method of claim 1, wherein the most recently written data comprises the first compressed data.

8. A non-transitory computer readable medium comprising instructions that, when executed, cause a machine to at least:

compress update data into second compressed update data, the update data representing an updated version of first data, the first data stored in a compressed format as first compressed data in a first space of the nonvolatile memory device, and the first compressed data indicated as a valid version by identification data stored in a header in the nonvolatile memory device;

write the second compressed update data to a second space of the nonvolatile memory device that does not include most recently written data; and

only when the second compressed update data is successfully written, update the identification data in the header to identify the second compressed update data in the second space as the valid version.

9. The non-transitory computer readable medium of claim 8, wherein the instructions, when executed, cause the machine to calculate a checksum, wherein a valid value of the checksum indicates a successful writing of the second compressed update data.

10. The non-transitory computer readable medium of claim 8, wherein the instructions, when executed, cause the machine to update the header in a dedicated space of the nonvolatile memory device.

11. The non-transitory computer readable medium of claim 8, wherein the instructions, when executed, further cause the machine to identify frequently updated data from among the update data, and write the identified frequently updated data in uncompressed form to a frequently updated data block of the nonvolatile memory device.

12. The non-transitory computer readable medium of claim 8, wherein when the second compressed update data is not successfully written, the instructions further cause the machine to repeat the writing of the second compressed update data and, when the second compressed update data is successfully written after repeating the writing, update the identification data to identify that the second compressed update data in the second space is the valid version.

13. The non-transitory computer readable medium of claim 8, wherein the second space of the nonvolatile memory device does not include the first compressed data.

14. A system comprising a processor and a nonvolatile memory device the processor to execute instructions to at least:

compress update data into second compressed update data, the update data representing an updated version of first data, the first data stored in a compressed format as first compressed data in a first space of the nonvolatile memory device, and the first compressed data identified as a valid version by identification data stored in a header in the nonvolatile memory device;

write the second compressed update data to a second space of the nonvolatile memory device that does not include a most recently written data; and

only when the second compressed update data is successfully written, update the identification data in the header to identify that the second compressed update data in the second space is the valid version.

15. The system of claim 14, wherein the system is a component of at least one_of a calculator, a PC motherboard, a cellular telephone, a printer, an all-in-one printer, a tablet computer, an e-reader, a router, and a network switch.

16. The system of claim 14, wherein the nonvolatile memory device comprises a data subspace designated for storing the header.

17. The system of claim 14, wherein the nonvolatile memory device comprises a data subspace designated for storing uncompressed data.

18. The system of claim 14, further comprising a random access memory on which the processor stores the compressed update data in response to a request for the valid version.

19. The system of claim 14, wherein the second space of the nonvolatile memory device does not include the first compressed data.