ERROR CONTROL IN A FLASH MEMORY DEVICE

• US 20100050053A1
• Filed: 08/22/2008
• Published: 02/25/2010
• Est. Priority Date: 08/22/2008
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Park, Jihoon, de Souza, Jorge Campello, Blaum, Mario, Djurdjevic, Ivana, Wilson, Bruce A.
• Granted Patent: US 8,213,229 B2
• Time in Patent Office: Days
• US Class Current: 714/773
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• 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: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles

Abstract

Flash memory devices and associated methods are described for controlling data errors in the devices through various forms of decoding, error correction, and wear concentration. To this end, a flash memory device may be partitioned into a plurality of sectors. Data may then be received from, for example, a host processor for storage within the flash memory device. Storage durations of the data are then estimated and the data is stored in the data sectors based on those estimated storage durations.

Claims

1. A method of using a flash memory device, the method comprising:

partitioning the flash memory device into at least first and second sectors, wherein the first sector is adapted to store data having a first range of storage durations and the second sector is adapted to store data having a second range of storage durations that is different than the first range of storage durations;

receiving first data to be written to the flash memory device;

estimating a storage duration for the first data; and

storing the first data in the first sector based on the estimated storage duration of the first data.

2. The method of claim 1, wherein estimating the storage duration for the first data comprises analyzing the first data to determine whether the first data is a data file or metadata.

3. The method of claim 1, further comprising analyzing wear of the flash memory device for use in partitioning the flash memory device by determining at least one of a number of write operations to the sectors and a number of errors occurring within the sectors.

4. The method of claim 1, further comprising:

reading the first data from the first sector of the flash memory device; and

decoding the first data with an error correction algorithm by evaluating data integrity of the first sector and selecting a data sequence, based on the data integrity of the first sector, to represent the first data read from the first sector.

5. The method of claim 4, further comprising decoding the data sequence using an error correction code and generating, with the error correction code, error information for use in determining a data integrity indicator of the first sector.

6. The method of claim 5, further comprising using the data integrity indicator of the first sector to repartition the flash memory device.

7. The method of claim 1, further comprising:

receiving second data for storage in the flash memory device;

estimating a storage duration for the second data; and

storing the second data in the second sector based on the estimated storage duration of the second data.

8. The method of claim 1, wherein estimating a storage duration for the first data comprises evaluating a write frequency of the first data.

9. A portable device that includes flash memory, the portable device comprising:

an array of flash memory cells; and

control logic communicatively coupled to the array of flash memory cells and adapted to control data storage within the flash memory cells, wherein the control logic is further adapted to estimate storage durations of data to be stored in the flash memory cells and partition the array of flash memory cells into at least first and second sectors, wherein the first sector is adapted to store data having a first range of storage durations and the second sector is adapted to store data having a second range of storage durations that is different than the first range of storage durations.

10. The portable device of claim 9, wherein the portable device is a cell phone, a personal digital assistant, a media player, a flash drive, or a combination thereof.

11. The portable device of claim 9, further comprising a wear analyzer adapted to determine at least one of a number of write operations to said at least first and second sectors of the flash memory cells and a number of errors associated with said at least first and second of the flash memory cells.

12. The portable device of claim 9, further comprising a first decoder adapted to decode data from the flash memory cells by selecting a data sequence, based on wear of the flash memory cells, to represent data being read from the flash memory cells.

13. The portable device of claim 12, further comprising a second decoder adapted to decode the data sequence using a second error correction algorithm and generate error information used in computing a data integrity indicator of the flash memory cells.

14. The portable device of claim 13, wherein the control logic is further adapted to repartition the array of flash memory cells based on the data integrity indicator of the flash memory cells.

15. A flash memory system, comprising:

an array of flash memory cells;

a partitioner adapted to partition the flash memory device into at least first and second sectors, wherein the first sector is adapted to store data having a first range of storage durations and the second sector is adapted to store data having a second range of storage durations that is different than the first range of storage durations; and

a data analyzer communicatively coupled to the partitioner and adapted to receive first data for storage in the flash memory cells, estimate a storage duration for the first data, and store the first data in the first sector based on the estimated storage duration of the first data.

16. The flash memory system of claim 15, wherein the data analyzer is further adapted to estimate the storage duration for the first data by determining whether the first data is a data file or metadata.

17. The flash memory system of claim 15, further comprising a wear analyzer communicatively coupled to the partitioner and adapted to analyze wear of the flash memory device by determining at least one of a number of write operations to the sectors and a number of errors occurring within said at least first and second sectors, wherein the wear analyzer is further adapted to generate a data integrity indicator based on the at least one of a number of write operations to the sectors and a number of errors occurring within said at least first and second sectors.

18. The flash memory system of claim 16, wherein the partitioner is further adapted to receive the data integrity indicator from the wear analyzer and repartition the flash memory device.

19. The flash memory system of claim 15, further comprising a first decoder adapted to read the first data from the first sector of the flash memory device and decode the first data by evaluating wear of the first sector and selecting a data sequence, based on the wear of the first sector, to represent the first data read from the first sector.

20. The flash memory system of claim 19, further comprising a second decoder that decodes the data sequence using an error correction code and generates, with the error correction code, error information for use in determining subsequent wear of the first sector.

21. The flash memory system of claim 15, wherein the data analyzer is further adapted to receive second data for storage in the flash memory device, estimate a storage duration for the second data, and store the second data in the second sector based on the estimated storage duration of the second data.

22. A method of using a flash memory device, the method comprising:

partitioning the flash memory device into a plurality of sectors, each having an associated range of storage durations;

receiving data to be written to the flash memory device;

estimating a storage duration for the data; and

storing the data in a first sector based on the estimated storage duration of the data.