Method of operating storage device to recover performance degradation due to retention characteristic and method of operating data processing system including the same

• US 10,572,158 B2
• Filed: 10/12/2016
• Issued: 02/25/2020
• Est. Priority Date: 11/20/2015
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sang Yong, Gahng, Shin Wook, Lee, Chul
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): Kabir, Enamul M
• Application Number:
  US15/291,094
• Publication Number:
  US 20170147209A1
• Time in Patent Office: 1,231 Days
• Field of Search: 714764
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• 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 3/0659 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]
• 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
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents

Abstract

A storage device may include a plurality of memory cells arranged in pages and blocks, each page including a row of memory cells, and each block including a plurality of pages of memory cells. The storage device may include a memory device, such as a nonvolatile memory device, which includes these items. A data recovery method for the storage device may include receiving by the storage device a first command corresponding to a first selected data recovery scheme. Based on the first command: a first target page scheme for performing error detection on the plurality of blocks is applied, target pages are read using the first target page scheme, and an amount of errors in each read target page is detected. In addition, it may be determined that a target page of a first block has at least a first threshold amount of errors, and based on the determination, data recovery for the first block may be performed by relocating all data stored in the first block to another block. Further, it may be determined that no read page in a second block has at least the first threshold amount of errors, and as a result, the data stored in the second block can be maintained.

Claims

1. A data recovery method for a storage device including a plurality of memory cells arranged in pages and blocks, each page including a row of memory cells, and each block including a plurality of pages of memory cells, the method comprising:

receiving by the storage device a first command corresponding to a first selected data recovery scheme; and

based on the first command;

applying a first target page scheme for performing error detection on the plurality of blocks;

reading target pages using the first target page scheme, and detecting an amount of errors in each read target page;

as part of the first selected data recovery scheme, determining that a target page of a first block has an amount of errors that falls within a first range of errors, a lower boundary of the first range of errors being a first threshold amount of errors, and based on the determination, performing data recovery for the first block by relocating all data stored in the first block to another block;

as part of the first selected data recovery scheme, determining that no read page in a second block has an amount of errors that falls within the first range of errors, and as a result, maintaining the data stored in the second block without relocating the data;

receiving by the storage device a second command corresponding to a second selected data recovery scheme; and

based on the second command;

applying a second target page scheme for performing error detection on at least the second block and one or more additional blocks;

reading at least one target page of the second block and at least one target page of the one or more additional blocks using the second target page scheme, and detecting a number of errors in each read target page of the second block;

as part of the second selected data recovery scheme, determining that a target page of the second block has an amount of errors lower than the first range of errors and that falls within a second range of errors, a lower boundary of the second range of errors being a second threshold amount, and based on the determination, performing data recovery for the second block by relocating all data stored in the second block to another block; and

determining that no read page in the one or more additional blocks has an amount of errors that falls within the second range of errors, and as a result, maintaining the data stored in the one or more additional blocks,

wherein the second threshold amount is smaller than the first threshold amount.

2. The data recovery method of claim 1, further comprising:

performing the receiving, applying, reading, and both determining steps for each of the first and second data recovery schemes during a data recovery operating mode of the storage device, the data recovery operating mode different from a normal read operating mode of the storage device.

3. The method of claim 1, wherein the second target page scheme is the same scheme as the first target page scheme.

4. The method of claim 1, further comprising:

determining a performance of the storage device; and

setting the first threshold amount based on the determined performance.

5. The method of claim 4, wherein the determined performance is a speed of reading the storage device.

6. The method of claim 1, wherein the first threshold amount of errors is a first threshold percentage of errors per data stored in a page.

7. A data recovery method for a storage device including a plurality of memory cells arranged in pages and blocks, each page including a row of memory cells, and each block including a plurality of pages of memory cells, the method comprising:

(a) using a first data recovery procedure at the storage device to recover data on the storage device, the first data recovery procedure using a first data relocation scheme that relocates a block of data when at least one page of the block is determined to have at least a first threshold amount of errors;

(b) receiving at the storage device a command to use a second, different data recovery procedure; and

(c) in response to the command, using the second data recovery procedure at the storage device to recover data on the storage device, the second data recovery procedure using a second data relocation scheme that relocates a block of data when at least one page of the block is determined to have at least a second threshold amount of errors, the second threshold amount being smaller than the first threshold amount.

8. The method of claim 7, further comprising:

prior to step (b), determining a level of performance of the storage device; and

receiving a selection of the second data recovery procedure based on the determined level of performance.

9. The method of claim 7, wherein:

the first data recovery procedure includes testing a plurality of blocks to determine, for each block, whether at least one page of the block has at least the first threshold amount of errors; and

the second data recovery procedure includes testing the plurality of blocks to determine, for each block, whether at least one page of the block has at least the second threshold amount of errors.

10. The method of claim 7, wherein the first data recovery procedure includes a selected target page scheme used to detect errors on pages of the storage device.

11. The method of claim 10, wherein the selected target page scheme is one of:

a first scheme that performs error detection on a plurality of target pages in each block for a set of blocks of the storage device, the error detection determining, for each target page of the plurality of target pages, whether the target page has at least the first threshold amount of errors;

a second scheme that performs error detection on a single target page in each block for a set of blocks of the storage device, the error detection determining, for the single target page in each block, whether the target page has at least the first threshold amount of errors; and

a third scheme that performs error detection on a plurality of target pages randomly selected from the set of blocks of the storage device, the error detection determining, for each target page of the plurality of target pages, whether the target page has at least the first threshold amount of errors.

12. The method of claim 11, wherein:

according to the first data relocation scheme, when none of the target pages of a particular block of the set of blocks is determined to have at least the first threshold amount of errors and at least one of the target pages of the particular block is determined to have one less than the first threshold amount of errors, the particular block is not relocated during the first data recovery procedure, and

according to the second data relocation scheme, when at least one page of a particular block is determined to have one less than the first threshold amount of errors, the particular block is relocated.

13. The method of claim 7, wherein the first threshold amount of errors corresponds to a first threshold number of bit errors, and the second threshold amount of errors corresponds to a second threshold number of bit errors.

14. A data recovery method for a memory device including a plurality of memory cells arranged in pages and blocks, each page including a row of memory cells, and each block including a plurality of pages of memory cells, the method comprising:

determining, by a host, a first performance level of the memory device;

based on the first performance level, selecting a data relocation scheme from among a plurality of data relocation schemes, the plurality of data relocation schemes including a first data relocation scheme and a second data relocation scheme;

sending, by the host, a first command to perform a first data recovery procedure on the memory device, the first data recovery procedure including using the first data relocation scheme, which relocates a block of data of the memory device based on at least one page of the block having at least a first threshold amount of errors, and does not relocate a block of data of the memory device when no pages of the block are determined to have more than a second threshold amount of errors, the second threshold amount being smaller than the first threshold amount;

determining, by the host, a second performance level of the memory device; and

based on the second performance level, sending, by the host, a second command to perform a second data recovery procedure on the memory device, the second data recovery procedure including using the second data relocation scheme, which relocates a block of data of the memory device based on at least one page of the block having the second threshold amount of errors.

15. The method of claim 14, wherein the first data recovery procedure occurs during a data recovery operating mode of the memory device, the data recovery operating mode different from a normal read operating mode of the memory device.

16. The method of claim 15, wherein the first data recovery procedure includes:

applying a first target page scheme for performing error detection on the plurality of blocks;

reading target pages using the first target page scheme, and detecting an amount of errors in each read target page;

determining that a target page of a first block has at least a first threshold amount of errors, and based on the determination, performing data recovery for the first block by relocating all data stored in the first block to another block; and

determining that no read page in a second block has at least the first threshold amount of errors, and as a result, maintaining the data stored in the second block.

17. The method of claim 15, wherein:

the second data recovery procedure relocates blocks of data for which at least one page is determined to have the second threshold amount of errors, and does not relocate blocks of data for which no pages are determined to have at the second threshold amount of errors, the first threshold amount of errors, or more than the first threshold amount of errors.