Open erase block read automation

• US 9,864,545 B2
• Filed: 10/28/2015
• Issued: 01/09/2018
• Est. Priority Date: 04/14/2015
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Ellis, Robert W., Mohan, Vidyabhushan, Frayer, Jack Edward
• Primary Examiner(s): Choe, Yong
• Application Number:
  US14/925,943
• Publication Number:
  US 20160306591A1
• Time in Patent Office: 804 Days
• 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
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7206 Reconfiguration of flash memory system
• CPC Class Codes: G06F 2212/7208 Multiple device management, e.g. distributing data over multiple flash devices
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

Systems, methods, and/or devices are used to automate read operations performed at an open erase block. In one aspect, the method includes: receiving a read command, at a storage device, to read data from non-volatile memory of the storage device. In response to receiving the read command, the method further includes: 1) reading data using a first set of memory operation parameters in response to a determination that the read command is not for reading data from a predefined portion of an open erase block (e.g., an erase block that is determined to be an open erase block) of the non-volatile memory and 2) reading data using a second set of memory operation parameters (i.e., the second set is distinct from the first set) in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory.

Claims

1. A method of managing a storage device that includes non-volatile memory, the method comprising:

receiving, at the storage device, a read command to read data from the non-volatile memory of the storage device; and

in response to receiving the read command,

determining whether the read command is for reading data from a predefined portion of an erase block of the non-volatile memory that is an open erase block;

in response to a determination that the read command is not for reading data from the predefined portion of an open erase block of the non-volatile memory, reading data from the non-volatile memory using a first set of memory operation parameters; and

in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory, reading data from the non-volatile memory using a second set of memory operation parameters that is different from the first set of memory operation parameters.

2. The method of claim 1, wherein the predefined portion of any open erase block of the non-volatile memory is a last written word line of the open erase block.

3. The method of claim 1, wherein:

the read command corresponds to a respective erase block in the non-volatile memory; and

the first set of memory operation parameters are memory operation parameters determined in accordance with an age metric or performance metric for the respective erase block corresponding to the read command.

4. The method of claim 1, further comprising obtaining the second set of memory operation parameters from a lookup table.

5. The method of claim 1, further comprising, prior to sending a read operation command to a non-volatile memory die to read data requested by the received read command, sending to the non-volatile memory die a precursor command to change a mode of reading data from the non-volatile memory, using the second set of memory operation parameters.

6. The method of claim 1, further comprising storing, in a status table in volatile memory, last written word line information for each open erase block in the non-volatile memory.

7. The method of claim 6, wherein determining whether the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory comprises performing a lookup in the status table.

8. The method of claim 6, further comprising removing information from the status table with respect to a particular erase block in conjunction with closing the particular erase block.

9. The method of claim 6, wherein the status table is stored in volatile memory of a storage controller of the storage device.

10. The method of claim 6, wherein:

the storage device includes a plurality of storage modules; and

each storage module has a local controller, a plurality of non-volatile memory devices; and

volatile memory in which a portion of the status table is stored.

11. The method of claim 10, wherein:

the read command is for reading data from a respective storage module of the plurality of storage modules; and

determining whether the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory comprises performing a lookup in a corresponding portion of the status table in the respective storage module of the plurality of storage modules.

12. The method of claim 6, further comprising storing the status table in the non-volatile memory in response to detection of a power fail event.

13. A storage device, comprising:

non-volatile memory;

one or more processors; and

one or more controller modules configured to;

receive a read command to read data from the non-volatile memory;

determine, in response to receiving the read command, whether the read command is for reading data from a predefined portion of an erase block of the non-volatile memory that is an open erase block;

read data from the non-volatile memory using a first set of memory operation parameters in response to a determination that the read command is not for reading data from the predefined portion of an open erase block of the non-volatile memory; and

read data from the non-volatile memory using a second set of memory operation parameters that is different from the first set of memory operation parameters in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory.

14. The storage device of claim 13, wherein the one or more controller modules include:

a command module to receive the read command to read data from the non-volatile memory;

a status lookup module to determine, in response to the command module receiving the read command, whether the read command is for reading data from the predefined portion of any open erase block of the non-volatile memory; and

a data read module to;

read data from the non-volatile memory using the first set of memory operation parameters in response to a determination that the read command is not for reading data from the predefined portion of an open erase block of the non-volatile memory; and

read data from the non-volatile memory using a second set of memory operation parameters that is different from the first set of memory operation parameters in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory.

15. The storage device of claim 13, further comprising:

a status table that stores last written word line information for each open erase block in the non-volatile memory; and

a plurality of storage modules, each storage module having a local controller and a plurality of non-volatile memory devices, wherein a portion of the status table is stored in each of the storage modules.

16. The storage device of claim 14, further comprising:

a status table that stores last written word line information for each open erase block in the non-volatile memory; and

a plurality of storage modules, each storage module comprising;

a local controller including an instance of the status lookup module and an instance of the data read module; and

a plurality of non-volatile memory devices, wherein a portion of the status table is stored in each of the storage modules;

wherein;

the read command is for reading data from a respective storage module of the plurality of storage modules; and

determining whether the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory comprises performing a lookup in a corresponding portion of the status table in the respective storage module of the plurality of storage modules.

17. The storage device of claim 13, wherein the predefined portion of any open erase block of the non-volatile memory is a last written word line of the open erase block.

18. The storage device of claim 13, wherein:

the read command corresponds to a respective erase block in the non-volatile memory of the storage device; and

the first set of memory operation parameters are memory operation parameters determined in accordance with an age metric or performance metric for the respective erase block corresponding to the read command.

19. A non-transitory computer-readable storage medium, storing one or more programs configured for execution by one or more processors of a storage device, the one or more programs including instructions that, when executed by the one or more processors, cause the storage device to:

receive a read command to read data from the non-volatile memory;

determine, in response to receiving the read command, whether the read command is for reading data from a predefined portion of an erase block of the non-volatile memory that is an open erase block;

read data from the non-volatile memory using a first set of memory operation parameters in response to a determination that the read command is not for reading data from the predefined portion of an open erase block of the non-volatile memory; and

read data from the non-volatile memory using a second set of memory operation parameters that is different from the first set of memory operation parameters in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory.

20. The non-transitory computer-readable storage medium of claim 19, wherein:

the storage device includes a storage controller that includes the one or more processors;

the one or more programs include one or more controller modules configured for execution by the one or more processors of the storage controller; and

the one or more controller modules include;

a command module to receive the read command to read data from the non-volatile memory;

a status lookup module to determine, in response to the command module receiving the read command, whether the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory; and

a data read module to;

read data from the non-volatile memory using the first set of memory operation parameters in response to a determination that the read command is not for reading data from the predefined portion of an open erase block of the non-volatile memory; and

read data from the non-volatile memory using a second set of memory operation parameters that is different from the first set of memory operation parameters in response to a determination that the read command is for reading data from the predefined portion of an open erase block of the non-volatile memory.