Direct file data programming and deletion in flash memories

• US 20060184718A1
• Filed: 02/16/2005
• Published: 08/17/2006
• Est. Priority Date: 02/16/2005
• Status: Abandoned Application

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Sinclair, Alan W., Smith, Peter J.
• Application Number:
  US11/060,174
• Publication Number:
  US 20060184718A1
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/16 for erasing blocks, e.g. arrays, words, groups

Abstract

Host system data files are written directly to a large erase block flash memory system with a unique identification of each file and offsets of data within the file but without the use of any intermediate logical addresses or a virtual address space for the memory. Directory information of where the files are stored in the memory is maintained within the memory system by its controller, rather than by the host. The file based interface between the host and memory systems allows the memory system controller to utilize the data storage blocks within the memory with increased efficiency.

Claims

1. A method of operating a re-programmable non-volatile memory system with a host system, the memory system having blocks of memory cells that are erased prior to new data being written therein, comprising:

receiving data addressed by a unique file identification,

receiving a command to delete a specified data file from the memory system,

identifying blocks of memory cells containing data rendered obsolete as a result of the delete command, and

thereafter erasing data from the identified blocks.

2. The method of claim 1, wherein at least one block of memory cells identified to contain obsolete data is full of obsolete data.

3. The method of claim 1, wherein at least one block of memory cells identified to contain obsolete data also contains data from at least one other file.

4. The method of claim 3, wherein, prior to erasing the at least one block of memory cells identified to also contain data from at least one other file, the data from said at least one other file is copied into another block.

5. The method of claim 1, wherein receiving data addressed by a unique file identification includes receiving data addressed with offsets within the identified file.

12. The method of claim 1, wherein receiving data addressed by a unique file identification includes receiving data addressed with offsets within the identified file.

6. A method of operating a re-programmable non-volatile memory system with a host system, the memory system having blocks of memory cells that are erased prior to new data being written therein, comprising:

receiving data addressed by a unique file identification,

storing the received data of a file in one or more blocks that do not contain data of any other file, and, if necessary, in a part of another block,

rendering the blocks of data containing data of the file but without data of any other file obsolete in response a command from the host to delete a file whose data are stored therein, and

thereafter erasing the obsolete data blocks prior to the host sending a command to program data that requires use of any of the obsolete data blocks to store new data.

7. The method of claim 6, wherein erasing the obsolete data blocks occurs during periods when the host is idle.

8. The method of claim 6, wherein the command that obsoletes a host file includes a command to delete or erase the file from the memory system.

9. The method of claim 6, wherein receiving data addressed by a unique file identification includes receiving data addressed with offsets within the identified file.

10. A method of operating a re-programmable non-volatile mass storage system having memory cells organized into blocks that are erased prior to any new data being written therein, comprising:

receiving data addressed by a unique file identification,

programming the received data at physical addresses within the blocks of memory cells, and

in response to receipt of a command to delete a given file that was previously programmed within blocks of memory cells, scheduling the blocks that contain only data of the given file to be erased and scheduling at least one block that contains data of the given file and valid data of some other file for consolidation of the valid data of said other file into another block.

11. The method of claim 10, wherein programming data includes programming the received data to fill an integer number of one or more blocks with data of the given file and partially fill said at least one block with residual data of the given file.