Ruggedized memory device

• US 20100153660A1
• Filed: 12/17/2008
• Published: 06/17/2010
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Western Digital Israel Limited (Western Digital Corporation)
• Original Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Inventors: Lasser, Menahem
• Granted Patent: US 8,266,365 B2
• Time in Patent Office: Days
• US Class Current: 711/154
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc

Abstract

A non-volatile storage device with built-in ruggedized features is disclosed. The device processes a write command to a logical block address by writing the data from the command to a non-volatile memory within the non-volatile storage device and conditionally associating the data received from the command with its corresponding logical block address. Two or more received write commands define a set of commands associated with an atomic transaction. When an end of set command is received, the device unconditionally associates the received data with each write command with its corresponding logical block address. If a power loss interrupts the reception of a set of commands, the non-volatile storage device may recover the last consistent data state before the atomic transaction was started. A write command transaction identifier allows the device to associate the command with a thread of commands that define an atomic transaction in a multithreaded system.

Claims

1. A method of processing an atomic transaction in a non-volatile storage device, comprising:

receiving a set of commands at the non-volatile storage device, wherein the set of commands comprises a plurality of write commands, and each write command is associated with a corresponding logical block address and comprises data;

processing each of the plurality of write commands, comprising;

(i) writing the data from each write command to a non-volatile memory within the non-volatile storage device; and

(ii) conditionally associating the data received from each write command with its corresponding logical block address;

receiving an end of set command indicating an end of the set of commands; and

in response to receiving the end of set command, and without moving the data within the non-volatile storage device, for each logical block address that is associated with a write command in the set of commands, unconditionally associating with the logical block address the data of the last command of the set of commands conditionally associated with the logical block address.

2. The method of claim 1, further comprising:

receiving a command indicating a start of the set of commands prior to receiving the set of commands.

3. The method of claim 1, wherein writing the data from each write command to a non-volatile memory within the non-volatile storage device comprises writing the data to a physical block.

4. The method of claim 3, wherein conditionally associating the data received from each command with its corresponding logical block address comprises associating the physical block with the logical block address, wherein a plurality of physical blocks are associated with the logical block address.

5. The method of claim 3, wherein processing each of the plurality of write commands further comprises erasing the physical block before writing the data to the physical block.

6. The method of claim 5, further comprising:

in response to receiving the end of set command, and without moving the data within the non-volatile storage device, for each logical block address that is associated with a write command in the set of commands, disassociating all physical blocks from the logical block address except for a most recently written physical block associated with the logical block address.

7. The method of claim 3, wherein processing each of the plurality of write commands further comprises:

(iii) if a previously allocated physical block is a most recently written block associated with a logical block address that is associated with a write command in the set of commands;

(A) reading a flag value for the previously allocated physical block;

(B) toggling the flag value to form a toggled flag value; and

(C) associating the toggled flag value with a newly allocated physical block, wherein writing the data to the physical block comprises writing the data to the newly allocated physical block.

8. The method of claim 7, further comprising:

in response to receiving the end of set command, and without moving the data within the non-volatile storage device, for each logical block address that is associated with a write command in the set of commands, disassociating all physical blocks from the logical block address except for a most recently written physical block having the toggled flag value.

9. The method of claim 3, wherein processing each of the plurality of write commands further comprises:

(iii) getting a value indicative of a version of a current consistent data state of the non-volatile storage device;

(iv) incrementing the value to form an incremented value; and

(v) associating the incremented value with the physical block.

10. The method of claim 9, wherein unconditionally associating with the logical block address the data of the last command of the set of commands conditionally associated with the logical block address comprises updating the value indicative of the current consistent data state of the non-volatile storage device with the incremented value.

11. A method of processing an atomic transaction in a non-volatile storage device, comprising:

receiving a set of commands at the non-volatile storage device, wherein the set of commands comprises a plurality of write commands, and each write command is associated with a corresponding logical block address and comprises data and a transaction identifier;

processing each of the plurality of write commands, comprising;

(i) writing the data from each write command to a non-volatile memory within the non-volatile storage device; and

(ii) conditionally associating the data received from each write command with its corresponding logical block address;

receiving an end of set command indicating an end of the set of commands associated with the transaction identifier; and

in response to receiving the end of set command, for each logical block address that is associated with a write command in the set of commands, unconditionally associating with the logical block address the data of the last command of the set of commands conditionally associated with the logical block address.

12. The method of claim 11, further comprising:

receiving a command indicating a start of the set of commands prior to receiving the set of commands.

13. The method of claim 11, wherein the transaction identifier comprises a value, and the value of the transaction identifier of each write command in the set of commands is identical.

14. The method of claim 11, wherein the transaction identifier comprises a flag operative to associate the write command with the set of commands.

15. The method of claim 11, wherein writing the data from each write command to a non-volatile memory within the non-volatile storage device comprises writing the data to a physical block.

16. The method of claim 15, wherein conditionally associating the data received from each command with its corresponding logical block address comprises associating the physical block with the logical block address, wherein a plurality of physical blocks are associated with the logical block address.

17. The method of claim 15, wherein processing each of the plurality of write commands further comprises (iii) writing the transaction identifier from each write command to a non-volatile memory within the non-volatile storage device.

18. The method of claim 17, wherein writing the transaction identifier to a non-volatile memory within the non-volatile storage device comprises associating the transaction identifier with the physical block.

19. The method of claim 11, further comprising adding the transaction identifier to a list of open transactions if the transaction identifier is not already in the list of open transactions.

20. The method of claim 19, further comprising removing the transaction identifier from the list of open transactions when the end of set command is received.

21. The method of claim 17, further comprising setting a transaction identifier value associated with the physical block to a pre-determined value after receiving the end of set command.

22. The method of claim 13, further comprising:

receiving an additional write command after the set of commands begins and before the end of set command is received, wherein the end of set command is associated with the set of commands, and the additional write command is not associated with the set of commands.

23. The method of claim 22, wherein the additional write command is associated with an additional set of commands, the additional set of commands comprising a plurality of additional write commands, each additional write command associated with an additional logical block address and comprising data and an additional transaction identifier, wherein the transaction identifier and the additional transaction identifier distinguishes the set of commands from the additional set of commands.

24. The method of claim 15, the processing further comprising (iii) erasing the physical block before writing the data to the physical block.

25. The method of claim 24, further comprising:

in response to receiving the end of set command, and without moving the data within the non-volatile storage device, for each logical block address that is associated with a write command in the set of commands, disassociating all physical blocks from the logical block address except for a most recently written physical block associated with the logical block address.

26. The method of claim 15, wherein processing each of the plurality of write commands further comprises:

(iii) if a previously allocated physical block is a most recently written block associated with a logical block address that is associated with a write command in the set of commands;

(A) reading a flag value for the previously allocated physical block;

(B) toggling the flag value to form a toggled flag value; and

(C) associating the toggled flag value with a newly allocated physical block, wherein writing the data to the physical block comprises writing the data to the newly allocated physical block.

27. The method of claim 26, further comprising:

in response to receiving the end of set command, and without moving the data within the non-volatile storage device, for each logical block address that is associated with a write command in the set of commands, disassociating all physical blocks from the logical block address except for a most recently written physical block having the toggled flag value.

28. The method of claim 15, wherein processing each of the plurality of write commands further comprises:

(iii) getting a value indicative of a version of a current consistent data state of the non-volatile storage device;

(iv) incrementing the value to form an incremented value; and

(v) associating the incremented value with the physical block.

29. The method of claim 28, wherein unconditionally associating with the logical block address the data of the last command of the set of commands conditionally associated with the logical block address comprises updating the value indicative of the current consistent data state of the non-volatile storage device with the incremented value.

30. A method of processing a read command in a non-volatile storage device, comprising:

receiving a read command, wherein the read command specifies requested data;

selecting data in response to receiving the read command according to one of two read procedures, wherein a first read procedure comprises selecting a most recently written version of the requested data not associated with an open transaction, and a second read procedure comprises selecting a most recently written version of the requested data; and

returning the data.

31. The method of claim 30, wherein the selecting of data is defined by a configurable parameter.

32. A method of writing data to a non-volatile storage device, comprising:

requesting a transaction identifier from the non-volatile storage device;

receiving the transaction identifier from the non-volatile storage device;

transmitting a set of commands to the non-volatile storage device, wherein the set of commands comprises a plurality of commands associated with the transaction identifier, and wherein at least one command in the set comprises data; and

transmitting an end of set command to the non-volatile storage device indicating an end of the set of commands associated with the transaction identifier.

33. The method of claim 32, wherein the non-volatile storage device is a unit-based non-volatile storage device.