Systems and methods for measuring the useful life of solid-state storage devices

• US 20070260811A1
• Filed: 05/08/2006
• Published: 11/08/2007
• Est. Priority Date: 05/08/2006
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: SiliconSystems, Inc. (Western Digital Corporation)
• Inventors: Diggs, Mark, Drossel, Gary, Merry, David
• Granted Patent: US 7,653,778 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7211 Wear leveling
• 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 non-volatile solid-state storage subsystem, such as a non-volatile memory device, maintains usage statistics reflective of the wear state, and thus the remaining useful life, of the subsystem'"'"'s memory array. A host system reads the usage statistics information, or data derived therefrom, from the subsystem to evaluate the subsystem'"'"'s remaining life expectancy. The host system may use this information for various purposes, such as to (a) display or report information regarding the remaining life of the subsystem; (b) adjust the frequency with which data is written to the subsystem; and/or (c) select the type(s) of data written to the subsystem.

Claims

1. A solid state storage subsystem, comprising:

an array of non-volatile solid state memory; and

a controller that accesses the array of non-volatile solid state memory in response to commands received from a host system;

wherein the controller is configured to maintain, within the solid-state storage system, usage statistics reflective of a current wear level of the array of non-volatile solid state memory, and to output information regarding said wear level.

2. The solid state storage subsystem of claim 1, wherein the usage statistics maintained by the controller include at least one counter value which indicates a number of program/erase cycles performed.

3. The solid state storage subsystem of claim 1, wherein the usage statistics maintained by the controller include a plurality of counter values, each of which corresponds to a respective memory block and reflects a wear level thereof.

4. The solid state storage subsystem of claim 3, wherein the counter values are stored in the respective blocks to which they correspond.

5. The solid state storage subsystem of claim 1, wherein the controller provides host access to at least some of the usage statistics.

6. The solid state storage subsystem of claim 1, wherein the controller outputs the information regarding the wear level, at least in part, by outputting at least some of the usage statistics to the host system.

7. The solid state storage subsystem of claim 1, wherein the controller outputs the information regarding the wear level, at least in part, by outputting one or more data values derived from the usage statistics.

8. The solid state storage subsystem of claim 1, wherein the controller outputs the information regarding the wear level, at least in part, by displaying wear level information on a display that is part of the solid state storage subsystem.

9. The solid state storage subsystem of claim 1, in combination with a program that is configured to use said information regarding the wear level to generate, on the host system, a graphical display depicting an estimate of a remaining life of the slid state storage system.

10. The solid state storage subsystem of claim 1, in combination with a storage manager program that is configured to use said information regarding the wear level to select a type of data to be written to the solid state storage subsystem.

11. The solid state storage subsystem of claim 1, in combination with a storage manager program that is configured to use said information regarding the wear level to vary a frequency with which data is written to the solid state storage subsystem.

12. The solid state storage subsystem of claim 1, in combination with a driver program, configured to use at least one vendor-specific ATA command to retrieve said information regarding the wear level from the solid state storage subsystem.

13. A data storage system, comprising:

a storage subsystem that connects to and stores data for a host system, the storage subsystem comprising;

a memory array comprising a plurality of solid-state memory devices having one or more data blocks; and

a controller configured to access usage data stored in the memory array, the usage data reflecting the number of times the one or more data blocks have been erased; and

program code configured to use said usage data to generate a display indicating an estimated remaining useful life of the storage subsystem.

14. The system of claim 13, wherein the display is configured as a meter that indicates a utilization of the storage subsystem relative to a percentage scale.

15. The system of claim 14, wherein the scale corresponds to a specified endurance of the storage subsystem.

16. The system of claim 15, wherein the meter is configured to provide indicia of a threshold relative to the percentage scale.

17. The system of claim 16, wherein the threshold is less than the specified endurance of the storage subsystem.

18. The system of claim 14, wherein the meter is configured to provide indicia of a time displayed relative to the percentage scale so as to indicate how much of the percentage has been used during a predetermined time period.

19. The system of claim 13, wherein the display is configured as a bar chart that indicates a utilization of the storage subsystem relative to a percentage scale.

20. A computer-readable medium having stored thereon a computer program which, when executed by a host computer, causes the host computer to use at least one vendor-specific ATA command to retrieve usage information from a solid state storage subsystem that is configured to maintain such usage information in a non-user-data memory area thereof, and to use said usage information to do at least one of the following:

(a) generate a graphical display depicting a remaining life of the solid state storage subsystem;

(b) select a type of data to be written to the solid state storage subsystem;

(c) vary a frequency with which data is written to the solid state storage subsystem, wherein the usage information is reflective of a number of erase cycles that have been executed by the solid state storage subsystem.

21. The computer-readable medium of claim 20, wherein the computer program is configured to use said usage information to generate said graphical display depicting the remaining life of the solid state storage subsystem.

22. The computer-readable medium of claim 20, wherein the computer program is configured to use said usage information to select a type of data to be written to the solid state storage subsystem.

23. The computer-readable medium of claim 20, wherein the computer program is configured to use said usage information to vary a frequency with which data is written to the solid state storage subsystem.

24. The computer-readable medium of claim 20, wherein the usage information comprises a plurality of counter values, and the computer program uses the counter values in combination to generate a value representing an estimated remaining useful life of the solid state storage system.