WEAR-FOCUSING OF NON-VOLATILE MEMORIES FOR IMPROVED ENDURANCE

• US 20120226962A1
• Filed: 03/04/2011
• Published: 09/06/2012
• Est. Priority Date: 03/04/2011
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Franceschini, Michele M., Jagmohan, Ashish
• Granted Patent: US 8,621,328 B2
• Time in Patent Office: Days
• US Class Current: 714/766
• CPC Class Codes: G06F 11/1012 using codes or arrangements adapted for a specific type of error G06F11/1048 takes precedence
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles

Abstract

Storing data in memory using wear-focusing techniques for improved endurance. A method for storing the data includes receiving write data to be written into a memory that is logically divided into a plurality of regions. The plurality of regions includes a first region and a second region that are implemented by the same memory technology. The memory is subject to degradation as a result of write operations. The write data is classified as dynamic data or static data. The write data is encoded using a first type of encoding in response to the write data being classified as dynamic. The write data encoded using the first type of encoding is stored in the first region of the memory. The write data is encoded using a second type of encoding and stored in the second region of the memory in response to classifying the write data as static data.

Claims

1. A computer implemented method for storing data in memory, the method comprising:

receiving write data to be written into a memory that is logically divided into a plurality of regions, the plurality of regions including a first region and a second region, the first region and the second region implemented by the same memory technology, and the memory subject to degradation as a result of write operations;

classifying the write data as dynamic data or static data;

in response to classifying the write data as dynamic data performing;

encoding the write data using a first type of encoding; and

storing the write data encoded using the first type of encoding in the first region of the memory; and

in response to classifying the write data as static data performing;

encoding the write data using a second type of encoding; and

storing the write data encoded using the second type of encoding in the second region of the memory.

2. The method of claim 1, wherein the memory technology is flash memory.

3. The method of claim 1, wherein the first type of encoding and the second type of encoding are the same.

4. The method of claim 1, wherein the first type of encoding detects and corrects more errors than the second type of encoding.

5. The method of claim 1, wherein the first region is smaller than the second region.

6. The method of claim 1, further comprising receiving a write address for the write data, wherein the classifying is performed by comparing a timestamp associated with the write address to a programmable threshold value.

7. The method of claim 1, further comprising receiving metadata for the write data, wherein the metadata is an input to the classifying.

8. The method of claim 1, wherein stored data is moved from the first region to the second region based on a re-classification of the stored data from dynamic to static.

9. The method of claim 1, wherein stored data is moved from the second region to the first region based on a re-classification of the stored data from static to dynamic.

10. The method of claim 1, wherein the memory comprises a plurality of memory devices and each memory device contains portions of more than one of the plurality of regions.

11. The method of claim 1, wherein the memory comprises a plurality of memory devices and each memory device is occupied by at most one of the plurality of regions.

12. The method of claim 1, further comprising performing wear-leveling of the data for each of the plurality of regions.

13. The method of claim 1, wherein a size of each of the plurality of regions is determined by a plotted frequency of writes, wherein a percentage of writes are stored in the first region based on a projected retention of the second region.

14. A system comprising:

a memory logically divided into a plurality of regions, the plurality of regions including a first region and a second region, the first region and the second region implemented by the same memory technology, and the memory subject to degradation as a result of write operations; and

a memory controller in communication with the memory, the memory controller configured to perform a method, the method comprising;

receiving write data;

classifying the write data as dynamic data or static data;

in response to classifying the write data as dynamic data performing;

encoding the write data using a first type of encoding; and

storing the write data encoded using the first type of encoding in the first region of the memory; and

in response to classifying the write data as static data performing;

encoding the write data using a second type of encoding; and

storing the write data encoded using the second type of encoding in the second region of the memory.

15. The system of claim 14, wherein the first type of encoding and the second type of encoding are the same.

16. The system of claim 14, wherein the first type of encoding detects and corrects more errors than the second type of encoding.

17. The system of claim 14, wherein the first region is smaller than the second region.

18. The system of claim 14, wherein the method further comprises receiving a write address for the write data, and the classifying is performed by comparing a timestamp associated with the write address to a programmable threshold value.

19. The system of claim 14, wherein the method further comprises receiving metadata for the write data, and the metadata is an input to the classifying.

20. The system of claim 14, wherein stored data is moved from the first region to the second region based on a re-classification of the stored data from dynamic to static, and moved from the second region to the first region based on a re-classification of the stored data from static to dynamic.

21. The system of claim 14, wherein the memory is a flash memory device.

22. A computer program product for storing data in memory, the computer program product comprising:

a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

receiving write data to be written into a memory that is logically divided into a plurality of regions, the plurality of regions including a first region and a second region, the first region and the second region implemented by the same memory technology, and the memory subject to degradation as a result of write operations;

classifying the write data as dynamic data or static data;

in response to classifying the write data as dynamic data performing;

encoding the write data using a first type of encoding; and

storing the write data encoded using the first type of encoding in the first region of the memory; and

in response to classifying the write data as static data performing;

encoding the write data using a second type of encoding; and

storing the write data encoded using the second type of encoding in the second region of the memory.

23. The computer program product of claim 22, wherein the memory technology is flash memory.

24. The computer program product of claim 22, wherein the first type of encoding detects and corrects more errors than the second type of encoding.

25. The computer program product of claim 22, wherein stored data is moved from the first region to the second region based on a re-classification of the stored data from dynamic to static, and moved from the second region to the first region based on a re-classification of the stored data from static to dynamic.