STORAGE SUBSYSTEM WITH MULTIPLE NON-VOLATILE MEMORY ARRAYS TO PROTECT AGAINST DATA LOSSES

• US 20080147962A1
• Filed: 12/15/2006
• Published: 06/19/2008
• Est. Priority Date: 12/15/2006
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: SiliconSystems, Inc. (Western Digital Corporation)
• Inventors: Merry, David E., Diggs, Mark S.
• Granted Patent: US 8,549,236 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2087 with a common controller
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence

Abstract

A storage subsystem contains multiple non-volatile memory arrays that are accessible to a host system when the storage subsystem is connected thereto. The storage subsystem implements commands and/or modes for enabling the host system to create and use backup copies of files, such that the host system can recover when files become corrupted or otherwise lost. In one embodiment, the storage subsystem presents the non-volatile memory arrays to the host'"'"'s operating system as distinct storage devices (e.g., ATA device 0 and 1), and implements special commands for copying data between these storage devices. The subsystem may alternatively present the memory arrays to the host operating system as a single storage device. The storage subsystem may have a standard form factor, such as a form factor commonly used for memory cards.

Claims

1. A storage subsystem comprising:

a first controller connected to, and being capable of writing data to and reading data from, a first solid-state non-volatile memory array;

a second controller connected to, and being capable of writing data to and reading data from, a second solid-state non-volatile memory array; and

a connector for connecting the storage subsystem to a host system, said connector coupled to the first and second controllers such that the first and second controllers are capable of receiving storage access commands from the host system;

wherein the first controller is capable of presenting at least a portion of the first non-volatile memory array to the host system as storage space of a first storage device, and the second controller is capable of presenting at least a portion of the second non-volatile memory array to the host system as storage space of a second storage device.

2. The storage subsystem as in claim 1, wherein the first controller is capable of presenting the first storage device to the host system as ATA device 0, and the second controller is capable of presenting the second storage device to the host system as ATA device 1.

3. The storage subsystem as in claim 2, wherein the storage subsystem is capable of being placed into a switch device mode in which the first non-volatile memory array corresponds to ATA device 1 and the second non-volatile memory array corresponds to ATA device 0.

4. The storage subsystem of claim 3, wherein the storage subsystem includes a physical switch that enables an operator to place the storage subsystem into the switch device mode.

5. The storage subsystem of claim 3, wherein the storage subsystem implements a command that enables the host system to place the storage subsystem into the switch device mode.

6. The storage subsystem as in claim 1, wherein the first and second controllers are capable of executing standard ATA storage access commands.

7. The storage subsystem of claim 6, wherein the first and second controllers are additionally capable of executing at least one non-standard command for backing up data from the first non-volatile memory array to the second non-volatile memory array.

8. The storage subsystem of claim 7, wherein the first and second controllers are additionally capable of executing at least one non-standard command for restoring backed up data from the second non-volatile memory array to the first non-volatile memory array.

9. The storage subsystem as in claim 1, wherein the storage subsystem is capable of being placed into a mirror mode in which, when the host system issues a command to write data to the first storage device, the storage subsystem automatically writes all of said data to both the first non-volatile memory array and the second non-volatile memory array.

10. The storage subsystem as in claim 1, wherein the first controller is additionally capable of accessing the second non-volatile memory array, and the second controller is additionally capable of accessing the first non-volatile memory array.

11. The storage subsystem as in claim 1, wherein the first and second controllers and the first and second memory arrays are housed within a housing that complies with a standard form factor used for memory cards.

12. The storage subsystem as in claim 11, wherein the standard form factor is one of the following:

CompactFlash, SecureDigital, PCMCIA, MultiMediaCard, SmartMedia, Memory Stick.

13. The storage subsystem as in claim 1, wherein the connector is a USB connector.

14. The storage subsystem as in claim 1, wherein the first non-volatile memory array stores operating system code such that the host system can boot from the storage system, and the second non-volatile memory array stores a backup copy of the operating system code.

15. The storage subsystem as in claim 14, in combination with said host system, wherein the host system is configured to boot from the first storage device, and to boot from the second storage device if unable to boot from the first drive, such that said backup copy is used if the operating system code in the first non-volatile memory array becomes corrupted.

16. The storage subsystem as in claim 1, further comprising a third controller that controls a third non-volatile memory array.

17. A storage subsystem, comprising:

first and second solid-state non-volatile memory arrays;

controller circuitry which is capable of writing data to, and reading data from, each of the first and second non-volatile memory arrays in response to ATA commands received from a host system; and

a connector for connecting the storage subsystem to the host system, said connector coupled to the controller circuitry;

wherein the controller circuitry is capable of copying data from one of the non-volatile memory arrays to the other non-volatile memory array in response to commands from the host system.

18. The storage subsystem of claim 17, wherein the controller circuitry is capable of presenting at least a portion of the first non-volatile memory array to the host system as storage space of a first ATA storage device, and is capable of concurrently presenting at least a portion of the second non-volatile memory array to the host system as storage space of a second ATA storage device.

19. The storage subsystem of claim 18, wherein the controller circuitry is capable of being placed by the host system into a mirror mode in which standard write commands to the first ATA storage device are effectively mirrored to the second ATA storage device such that data is automatically mirrored across the first and second non-volatile memory arrays.

20. The storage subsystem of claim 17, wherein the controller circuitry implements a restore command that causes data backed up to the second non-volatile memory array to be restored to the first non-volatile memory array.

21. The storage subsystem of claim 17, wherein the controller circuitry and the first and second non-volatile memory arrays are housed within a housing that complies with a standard form factor used for memory cards.

22. The storage subsystem of claim 21, wherein the standard form factor is one of the following:

CompactFlash, SecureDigital, PCMCIA, MultiMediaCard, SmartMedia, Memory Stick.

23. The storage subsystem of claim 17, wherein the connector is a USB connector.

24. The storage subsystem of claim 17, wherein the first non-volatile memory array contains executable operating system code and the second non-volatile memory array contains a backup copy of the executable operating system code.

25. The storage subsystem as in claim 24, in combination with said host system, wherein the host system is configured to use the backup copy to boot if unable to boot using the operating system code stored in the first non-volatile memory.

26. The storage subsystem of claim 17, wherein the controller circuitry comprises a first controller that controls the first non-volatile memory array, and comprises a second controller that controls the second non-volatile memory array.

27. The storage subsystem of claim 17, wherein the storage subsystem further comprising a third non-volatile memory array which is capable of being controlled by the controller circuitry.

28. The storage subsystem of claim 27, wherein the controller circuitry is capable of using at least the first, second and third non-volatile memory arrays to implement a RAID configuration.

29. A storage subsystem, comprising:

first and second solid-state non-volatile memory arrays;

controller circuitry which is capable of writing data to, and reading data from, each of the first and second non-volatile memory arrays in response to commands received from a host system; and

a connector for connecting the storage subsystem to the host system, said connector coupled to the controller circuitry;

wherein the controller circuitry is capable of maintaining the second non-volatile memory array hidden from the host system while using the second non-volatile memory array to maintain a backup copy of data written by the host system to the first non-volatile memory array, such that the backup copy is maintained transparently to the host system.

30. The storage subsystem as in claim 29, wherein the controller circuitry is further capable of using the backup copy maintained in the second non-volatile memory array to restore lost data lost from the first non-volatile memory array.

31. The storage subsystem as in claim 29, wherein the controller circuitry implements standard ATA storage access commands, and implements at least one non-standard command that enables the host system to access backup data stored in the second non-volatile memory array.

32. The storage subsystem as in claim 29, wherein the controller circuitry and the first and second non-volatile memory arrays are housed within a housing that complies with a standard form factor used for memory cards.