RETIREMENT OF PHYSICAL MEMORY BASED ON DWELL TIME

• US 20150161035A1
• Filed: 12/09/2013
• Published: 06/11/2015
• Est. Priority Date: 12/09/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: FISHER, TIMOTHY J., FRY, AARON D.
• Granted Patent: US 9,390,003 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 2029/0409 Online test
• CPC Class Codes: G11C 2029/0411 Online error correction
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check

Abstract

In at least one embodiment, a data storage system includes a non-volatile memory array including a plurality of regions of physical memory. The data storage system further includes a controller that controls read and write access to the memory array and retires selected ones of the plurality of regions of physical memory from use. The controller determines whether or to not to retire a particular region among the plurality of regions of physical memory from use based on a dwell time of data stored in the particular region.

Claims

1. A data storage system, comprising:

a controller configured to be coupled to a non-volatile memory array including a plurality of regions of physical memory, wherein the controller controls read and write access to the memory array and retires selected ones of the plurality of regions of physical memory from use, and wherein the controller determines whether or to not to retire a particular region among the plurality of regions of physical memory from use based on a dwell time of data stored in the particular region.

2. The data storage system of claim 1, wherein the controller determines whether or not to retire the particular region in response to detection of a data error in the data stored in the particular region.

3. The data storage system of claim 1, wherein:

the data storage system further includes the non-volatile memory array;

the dwell time is stored in the memory array in association with the particular region; and

the controller accesses the dwell time for the particular region from the particular region.

4. The data storage system of claim 1, wherein the controller determines not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold.

5. The data storage system of claim 4, wherein:

the controller determines not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region failing to satisfy an error count threshold; and

the controller determines to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region satisfying an error count threshold.

6. The data storage system of claim 1, wherein the particular region is a page.

7. A program product, comprising:

a storage device; and

program code stored in storage device that, when executed by a controller that controls read and write access to a non-volatile memory array including a plurality of regions of physical memory, causes the controller to perform;

the controller determining whether or to not to retire a particular region among the plurality of regions of physical memory from use based on a dwell time of data stored in the particular region; and

the controller, responsive to determining to retire the particular region from use, retiring the particular region from use.

8. The program product of claim 7, wherein the program code further causes the controller to perform determining whether or not to retire the particular region in response to detection of a data error in the data stored in the particular region.

9. The program product of claim 7, wherein:

the dwell time is stored in the memory array in association with the particular region; and

the program code further causes the controller to perform accessing the dwell time for the particular region from the particular region.

10. The program product of claim 7, wherein the determining includes the controller determining not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold.

11. The program product of claim 10, wherein:

the determining includes the controller determining not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region failing to satisfy an error count threshold; and

the controller determining to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region satisfying an error count threshold.

12. The program product of claim 7, wherein the particular region is a page.

13. A method of operating a data storage system, comprising:

a controller controlling reading from and writing to a non-volatile memory array;

the controller determining whether or to not to retire a particular region among the plurality of regions of physical memory from use based on a dwell time of data stored in the particular region; and

the controller, responsive to determining to retire the particular region from use, retiring the particular region from use.

14. The method of claim 13, and further comprising the controller performing the determining in response to detection of a data error in the data stored in the particular region.

15. The method of claim 13, wherein:

the dwell time is stored in the memory array in association with the particular region; and

the method further comprises the controller accessing the dwell time for the particular region from the particular region.

16. The method of claim 13, wherein the determining includes the controller determining not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold.

17. The method of claim 16, wherein:

the determining includes the controller determining not to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region failing to satisfy an error count threshold; and

the controller determining to retire the particular region from use in response to the dwell time failing to satisfy a dwell time threshold and an error count for the particular region satisfying an error count threshold.

18. The method of claim 13, wherein the particular region is a page.