Method of storing transformed units of data in a memory system having fixed sized storage blocks

• US 20070086260A1
• Filed: 10/13/2005
• Published: 04/19/2007
• Est. Priority Date: 10/13/2005
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Corporation (Western Digital Corporation)
• Inventors: Sinclair, Alan
• Granted Patent: US 7,529,905 B2
• Time in Patent Office: Days
• US Class Current: 365/230.30
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/401 Compressed data

Abstract

A change in the amount of data to be stored that results from various encoding, compression, encryption or other data transformation algorithms, is handled by individually identifying distinct units of the transformed data and storing such units in physical succession within storage blocks of a memory system such as flash memory. The data being stored may come from a host system external to the memory system or from an application running on a processor within the memory system.

Claims

1. A method of operating a re-programmable non-volatile memory system, wherein data are stored in a plurality of distinct blocks of data storage elements, comprising:

dividing a logical address range of data into a plurality of distinct units of addresses,

transforming the data of the units in a manner that results in at least some of the transformed units individually containing a different amount of data than existed prior to the transformation,

storing the transformed data of the units in one or more of the storage element blocks, and

identifying the storage locations of the transformed data of individual units by at least one data group having boundaries coincident with boundaries of the transformed unit.

2. The method of claim 1, wherein identifying the storage locations of the transformed data of individual units additionally includes identifying said at least one data group having boundaries coincident with boundaries of the storage element blocks.

3. The method of claim 1, which further comprises modifying at least one transformed unit of data stored in one or more of the storage element blocks by:

reading data of said at least one transformed unit from the memory system,

reverse transforming the data read from said at least one transformed unit, thereby to reconstruct the data of at least one unit,

modifying the reconstructed data of said at least one unit,

transforming the modified reconstructed data of said at least one unit,

storing the transformed reconstructed data in one or more of the storage element blocks, and

identifying the storage locations of the transformed reconstructed data of individual units by at least one data group having boundaries coincident with boundaries of the transformed unit and any physical boundaries of the storage element blocks.

4. The method of claim 1, wherein transforming the data includes at least one of encoding, compressing or encrypting the data.

5. The method of claim 4, wherein transforming the data results in said at least some the transformed units of data including units individually containing a lesser amount of data than existed prior to the transformation.

6. The method of claim 4, wherein transforming the data results in said at least some the transformed units of data including units individually containing a greater amount of data than existed prior to the transformation.

7. The method of claim 1, wherein dividing the logical address range of data into a plurality of distinct units of addresses includes dividing the logical address range of data into a plurality of equally sized units of addresses.

8. The method of claim 7, wherein the logical address range that is divided into a plurality of equally sized units of addresses is that of a host file object.

9. The method of claim 7, wherein the logical address range that is divided into a plurality of equally sized units of addresses is that of a memory system logical address space across which a plurality of host file objects are addressed.

10. The method of claim 1, wherein the data that is transformed originates with a host external of the memory system.

11. The method of claim 1, wherein the data that is transformed originates with an application being executed within the memory system.

12. The method of claim 1, wherein transforming the data includes transforming the data into transformed units that individually contain a lesser amount of data than a storage capacity of individual storage element blocks.

13. The method of claim 1, wherein identifying the storage locations of the transformed data includes linking together segments of a data group that reside in different storage element blocks.

14. The method of claim 1, wherein identifying the storage locations of the transformed data includes avoiding elimination of the boundaries of said at least one data group within the storage element block that are coincident with boundaries of the transformed unit.

15. The method of claim 14, which further comprises:

storing additional data units without transformation in at least one additional of the storage element blocks,

identifying the storage locations of the additional data by at least one additional data group within at least one of the storage element blocks, and

eliminating boundaries of said at least one additional data group within said at least one of the storage element blocks that are coincident with boundaries of the additional data units.

16. The method of claim 1, wherein memory system is a flash memory system and the distinct blocks contain the smallest number of data storage elements that are simultaneously erasable.

17. The method of claim 1, wherein memory system is a flash memory system and the distinct blocks contain two or more units of storage elements that are linked together and individually contain the smallest number of storage elements that are simultaneously erasable.

18. A method of operating a re-programmable non-volatile memory system, wherein the memory system includes an array of memory cells organized into operating blocks of cells, comprising:

dividing data received by the memory system into equal sized units of data that individually contain an amount of data equal to or less than a storage capacity of the individual memory cell blocks,

transforming the individual units of received data by at least one of encoding, compressing or encrypting the received data in a manner that at least some of the transformed units of data individually contain a different amount of data than existed prior to transformation,

writing the transformed units of data into one or more of the memory cell blocks,

defining groups of the written transformed data to have boundaries coincident with at least boundaries of the transformed units of data and physical boundaries of the memory blocks, and

avoiding elimination of the boundaries of the defined groups of data coincident with boundaries of the transformed units of data that are within the boundaries of the memory cell blocks.

19. The method of claim 18, additionally comprising within the memory system, in response to receiving data that updates data within at least one individual unit of previously received data that has been transformed and written to the memory:

reading the groups of transformed data that form said at least one transformed individual unit of data,

reverse transforming the read groups of transformed data by at least one of decoding, decompressing or decrypting the read data, thereby reconstructing said at least one individual unit of data,

thereafter modifying the reconstructed individual unit of data with the received update data,

thereafter transforming the modified unit of data by at least one of encoding, compressing or encrypting the modified reconstructed data,

rewriting the transformed modified unit of data into one or more of the memory cell blocks, and

defining groups of rewritten data having boundaries coincident with at least boundaries of the transformed modified unit of data and physical boundaries of the memory blocks.

20. The method of claim 18, wherein transforming the data results in at least some of the transformed units of data including units that individually contain a lesser amount of data than existed prior to the transformation.

21. The method of claim 18, wherein transforming the data results in at least some of the transformed units of data including units that individually contain a greater amount of data than existed prior to the transformation.

22. The method of claim 18, wherein defining groups of the transformed data includes linking together segments of a data group that reside in different blocks of cells.

23. The method of claim 18, which further comprises:

storing additional units of data received by the memory system without transformation in at least one additional of the memory cell blocks,

identifying the storage locations of the additional data units by additional data groups within the memory cell blocks, and

eliminating boundaries of the additional data groups coincident with boundaries of the additional units of data and within the memory cell blocks.

24. The method of claim 18, wherein memory system is a flash memory system and the distinct blocks contain the smallest number of memory cells that are simultaneously erasable.

25. The method of claim 18, wherein memory system is a flash memory system and the distinct blocks contain two or more units of memory cells that are operatively linked together and individually contain the smallest number of memory cells that are simultaneously erasable.

26. The method of claim 18, wherein the method is carried out in a memory system module that is removably connectable to a host device by a memory connector though which the data are received.

27. The method of claim 18, wherein the data received by the memory system originates from an application program executed by a processor within the memory system.