Systems and methods of storing data

• US 9,032,269 B2
• Filed: 12/19/2011
• Issued: 05/12/2015
• Est. Priority Date: 07/22/2011
• Status: Expired due to Fees

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Sharon, Eran, Alrod, Idan, Litsyn, Simon
• Primary Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US13/329,819
• Publication Number:
  US 20130024748A1
• Time in Patent Office: 1,240 Days
• Field of Search: 714/763, 711/103, 365/185.33
• US Class Current: 714/763
• CPC Class Codes: G06F 11/1044 with specific ECC/EDC distribution
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 2211/5641 Multilevel memory having cells with different number of storage levels
• CPC Class Codes: G11C 29/78 using programmable devices
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A method of writing data includes receiving data pages to be stored in a data storage device and generating codewords corresponding to the received data pages. The codewords are stored to physical pages of a first memory portion of the data storage device. A first portion of a particular codeword that corresponds to a particular data page is stored at a first physical page of the first memory portion. A second portion of the particular codeword is stored at a second physical page of the first memory portion. The codewords are copied from the physical pages of the first memory portion to a physical page of a second memory portion of the data storage device.

Claims

1. A method for writing data, the method comprising:

in a data storage device, performing;

receiving data pages to be stored in the data storage device;

generating codewords corresponding to the received data pages;

storing the codewords to physical pages of a first memory portion of the data storage device, wherein a first portion of a particular codeword that corresponds to a particular data page is stored at a first physical page of the first memory portion and wherein a second portion of the particular codeword is stored at a second physical page of the first memory portion; and

copying the codewords from the physical pages of the first memory portion to a physical page of a second memory portion of the data storage device.

2. The method of claim 1, wherein the particular codeword is a concatenated codeword that includes multiple sub-codes and joint parity of the multiple sub-codes.

3. The method of claim 2, wherein each of the multiple sub-codes includes a sub-code data portion and a sub-code parity portion, wherein the first portion of the particular codeword includes the sub-code data portions and wherein the second portion of the particular codeword includes the joint parity.

4. The method of claim 3, wherein generating and storing the multiple sub-codes and the joint parity enables multi-phase decoding of each of the sub-codes.

5. The method of claim 1, wherein the data storage device includes a flash memory, wherein the first memory portion includes single-level cells (SLC) of the flash memory, and wherein the second memory portion includes multi-level cells (MLC) of the flash memory.

6. The method of claim 5, wherein the physical page of the second memory portion is a single MLC wordline.

7. The method of claim 5, wherein each of the multi-level cells is configured to store data according to a first number of bits per cell, wherein a second number corresponds to a count of the received data pages, and wherein the second number equals the first number.

8. The method of claim 7, wherein the codewords are stored to a third number of the physical pages of the first memory portion, the third number greater than the second number.

9. The method of claim 1, wherein the particular codeword includes user data, first parity bits, and second parity bits, wherein the user data and the first parity bits are included in the first portion of the particular codeword, and wherein the second parity bits are included in the second portion of the particular codeword.

10. The method of claim 9, wherein the physical page of the second memory portion includes a first logical page, a second logical page, and a third logical page, wherein the first portion of the particular codeword is copied to the first logical page, wherein the second portion of the particular codeword is copied to the second logical page, and wherein a third portion of the particular codeword is copied to the third logical page.

11. The method of claim 1, wherein the data pages are received from a host device while the data storage device is operatively coupled to the host device.

12. The method of claim 1, wherein each physical page of the first memory portion has a substantially equal probability of being programmed with the first portion of the particular codeword or with the second portion of the particular codeword.

13. The method of claim 1, wherein relative positions of codewords portions in the physical pages of the first portion of the memory are maintained when the codeword portions are copied from the first memory portion to logical pages of the physical page of the second memory portion.

14. The method of claim 1, further comprising, in response to receiving a request from a host device for a particular data portion:

reading a first portion of a codeword corresponding to the requested data portion from a first page via a single page read;

initiating a first decode operation to decode the requested data portion based on read data and read parity from the first page; and

in response to a decoding failure of the first decode operation;

reading, from a second page, a second portion of the codeword corresponding to the requested data portion; and

initiating a second decode operation to decode the requested data portion based on the read data and the read parity and further based on read joint parity from the second portion of the codeword.

15. A data storage device comprising:

a memory with physical pages; and

a controller configured to generate codewords corresponding to data pages that are received from a host device while the data storage device is operatively coupled to the host device and to store the codewords to physical pages of a first portion of the memory, wherein a first portion of a particular codeword that corresponds to a particular data page is stored at a first physical page of the first memory portion and wherein a second portion of the particular codeword is stored at a second physical page of the first memory portion,

wherein the data storage device is configured to copy the codewords from the first portion of the memory to a physical page of a second portion of the memory.

16. The data storage device of claim 15, wherein the particular codeword is a concatenated codeword that includes multiple sub-codes and joint parity of the multiple sub-codes to enable multi-phase decoding of each of the sub-codes.

17. The data storage device of claim 16, wherein each of the multiple sub-codes includes a sub-code data portion and a sub-code parity portion, wherein the first portion of the particular codeword includes the sub-code data portions and wherein the second portion of the particular codeword includes the joint parity.

18. The data storage device of claim 15, wherein the memory includes a flash memory, wherein the first portion of the memory is a single level cell (SLC) portion of the flash memory, and wherein the second portion of the memory is a multi-level cell (MLC) portion of the flash memory.

19. The data storage device of claim 18, wherein the physical page of the second portion of the memory is a single MLC wordline.

20. The data storage device of claim 18, wherein the MLC portion is configured to store data according to a first number of bits per cell, wherein the controller is configured to generate the codewords corresponding to a second number of the data pages that are received, and wherein the second number equals the first number.

21. The data storage device of claim 20, further comprising an error correction coding (ECC) engine, wherein the controller is configured to provide the data pages to the ECC engine to generate the codewords.

22. The data storage device of claim 20, wherein the codewords are stored to a third number of the physical pages of the first memory portion, the third number greater than the second number.

23. The data storage device of claim 15, wherein the particular codeword includes user data, first parity bits, and second parity bits, wherein the user data and the first parity bits are included in the first portion of the particular codeword, and wherein the second parity bits are included in the second portion of the particular codeword.

24. The data storage device of claim 23, wherein the physical page of the second portion of the memory includes a first logical page, a second logical page, and a third logical page, wherein the first portion of the particular codeword is copied to the first logical page, wherein the second portion of the particular codeword is copied to the second logical page, and wherein a third portion of the particular codeword is copied to the third logical page.

25. The data storage device of claim 15, wherein the controller is configured to provide each physical page of the first memory portion with a substantially equal probability of being programmed with the first portion of the particular codeword or with the second portion of the particular codeword.

26. The data storage device of claim 15, wherein relative positions of codeword portions in the physical pages of the first memory portion are maintained when the codeword portions are copied to logical pages of the physical page of the second memory portion.

27. The data storage device of claim 15, wherein the controller is configured, in response to receiving a request from the host device for a particular data portion, to read a first portion of a codeword corresponding to the requested data portion from a first page via a single page read and initiate a first decode operation to decode the requested data portion based on read data and read parity from the first page, and wherein the controller is further configured, in response to a decoding failure of the first decode operation, to read a second portion of the codeword corresponding to the requested data portion from a second page and to initiate a second decode operation to decode the requested data portion based on the read data and the read parity and further based on read joint parity from the second page.

28. A method for writing data into a multi-level cell (MLC) flash memory device of B bits per cell, wherein B is a positive number, the method comprising:

receiving B data pages to be stored in the memory device;

encoding each of the B data pages into corresponding one or more codewords;

for each of the B data pages, storing the corresponding one or more codewords into single level cell (SLC) cells in the memory device, wherein for at least one of the B data pages the corresponding one or more codewords are stored into more than one SLC page; and

copying all of the codewords corresponding to the B data pages from the SLC cells into a wordline of MLC cells.

29. A data storage device comprising:

a multi-level cell (MLC) flash memory device of B bits per cell, wherein B is a positive number; and

a controller coupled to the MLC flash memory device, wherein the controller is configured to receive B data pages to be stored in the MLC flash memory device and encode each of the B data pages into corresponding one or more codewords,

wherein the data storage device is configured, for each of the B data pages, to store the corresponding one or more codewords into single level cell (SLC) cells in the MLC flash memory device, wherein for at least one of the B data pages the corresponding one or more codewords are stored into more than one SLC page, and

wherein the data storage device is further configured to copy all of the codewords corresponding to the B data pages from the SLC cells into a wordline of MLC cells.