STORAGE DEVICE WITH FLASH MEMORY AND DATA STORAGE METHOD

• US 20100318879A1
• Filed: 05/17/2010
• Published: 12/16/2010
• Est. Priority Date: 06/11/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: YU, Bum-seok
• Granted Patent: US 9,037,776 B2
• Time in Patent Office: Days
• US Class Current: 714/758
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0873 Mapping of cache memory to specific storage devices or parts thereof
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/096 Checksums
• CPC Class Codes: H03M 13/098 using single parity bit

Abstract

A method of storing write data in flash memory incorporated in a storage device, the method includes; receiving write data and a logical block address (LBA) for the flash memory, determining whether the LBA exists in the cache memory, if the LBA exists in the cache memory, comparing the write data with cache data stored in the cache memory at a location associated with the LBA, and if the write data and the cache data are the same, terminating operation of the storage device without programming the write data to the flash memory, else updating an error detection information lookup table entry associated with the LBA and programming the write data to the flash memory, and if the LBA does not exist in the cache memory, updating the error detection information lookup table entry associated with the LBA and programming the write data to the flash memory.

Claims

1. A method of storing write data in a storage device including a flash memory and a cache memory, the method comprising:

receiving a write command in the storage device, wherein the write command comprises write data to be stored in the flash memory and a logical block address (LBA) in the flash memory at which the write data is to be stored;

determining whether the LBA exists in the cache memory;

if the LBA exists in the cache memory, comparing the write data with cache data stored in the cache memory at a location associated with the LBA, and if the write data and the cache data are the same, terminating operation of the storage device without programming the write data to the flash memory, else updating an error detection information lookup table entry associated with the LBA and programming the write data to the flash memory; and

if the LBA does not exist in the cache memory, updating the error detection information lookup table entry associated with the LBA and programming the write data to the flash memory.

2. The method of claim 1, wherein the storage device is a solid-state drive (SSD).

3. The method of claim 1, wherein the cache memory is a DRAM memory.

4. The method of claim 1, further comprising:

obtaining first error detection information related to the write data, and obtaining second error detection information related to the cache data; and

if the LBA exists in the cache memory, comparing the first error detection information with the second error detection information, before comparing the write data and the cache data, and if the first error detection information and the second error detection information are the same then comparing the write data and the cache data,

else if the first error detection information and the second error detection information are not the same, updating the error detection information lookup table entry associated with the LBA and programming the write data to the flash memory without comparing the write data and the cache data.

5. The method of claim 4, wherein the first error detection information and the second error detection information are generated using at least one selected from the group consisting of a cycle redundancy check (CRC) method, a parity check method, and a checksum method.

13. The storage device of claim 1, wherein the cache memory is a DRAM memory.

6. A method of storing write data in a storage device including a flash memory and a cache memory, the method comprising:

receiving a write command in the storage device, wherein the write command comprises write data to be stored in the flash memory and a logical block address (LBA) in the flash memory at which the write data is to be stored;

determining whether the LBA exists in the cache memory;

if the LBA does not exist in the cache memory, reading data from the flash memory with reference to the LBA and storing the read data to the cache memory at a location associated with the LBA as cache data;

if the LBA exists in the flash memory and if the LBA does not exist in the cache memory, then comparing the write data with the cache data, and if the write data and the cache data are the same, terminating operation of the storage device without programming the write data to the flash memory, else updating an error detection information lookup table entry associated with the LBA and programming the write data to the flash memory.

7. The method of claim 6, wherein the storage device is a solid-state drive (SSD).

8. The method of claim 6, wherein the cache memory is a DRAM memory.

9. The method of claim 6, further comprising:

obtaining first error detection information related to the write data, and obtaining second error detection information related to the cache data; and

if the LBA exists in the cache memory and if the LBA does not exist in the cache memory following the reading of the flash memory and storing of the read data in the cache memory, comparing the first error detection information with the second error detection information, before comparing the write data and the cache data, and if the first error detection information and the second error detection information are the same then comparing the write data and the cache data,

else if the first error detection information and the second error detection information are not the same, updating the error detection information lookup table entry associated with the LBA and programming the write data to the flash memory without comparing the write data and the cache data.

10. The method of claim 9, wherein the first error detection information and the second error detection information are generated using at least one selected from the group consisting of a cycle redundancy check (CRC) method, a parity check method, and a checksum method.

11. A storage device comprising:

an interface unit configured to receive a write command from a host, wherein the write command comprises write data to be stored in the flash memory and a logical block address (LBA) in the flash memory at which the write data is to be stored;

a controller configured to control operation of a flash memory and a cache memory, and further configured to determining whether the LBA exists in the cache memory;

if the LBA exists in the cache memory, the controller is configured to compare the write data with cache data stored in the cache memory at a location associated with the LBA, and if the write data and the cache data are the same, terminate operation of the storage device without programming the write data to the flash memory, else update an error detection information lookup table entry associated with the LBA and program the write data to the flash memory; and

if the LBA does not exist in the cache memory, the controller is configure to update the error detection information lookup table entry associated with the LBA and program the write data to the flash memory.

12. The storage device of claim 11, wherein the storage device is a solid-state drive (SSD).

14. The storage device of claim 11, wherein the controller is further configured to obtain first error detection information related to the write data and second error detection information related to the cache data;

and

if the LBA exists in the cache memory, the controller is configured to compare the first error detection information with the second error detection information, before comparing the write data and the cache data, and if the first error detection information and the second error detection information are the same then compare the write data and the cache data,

else if the first error detection information and the second error detection information are not the same, the controller is configured to update the error detection information lookup table entry associated with the LBA and program the write data to the flash memory without comparing the write data and the cache data.

15. The storage device of claim 14, wherein the controller is further configured to generate the first error detection information and the second error detection information using at least one of a cycle redundancy check (CRC) method, a parity check method, and a checksum method.