Logically-addressed file storage methods

• US 20070136555A1
• Filed: 12/13/2005
• Published: 06/14/2007
• Est. Priority Date: 12/13/2005
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Sinclair, Alan
• Granted Patent: US 7,877,540 B2
• Time in Patent Office: Days
• US Class Current: 711/203
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

Files that are mapped to a logical address range by a host become logically fragmented prior to being sent to a memory system. Subsequently, the logically fragmented portions are reassembled when they are stored in blocks in the memory system. The host supplies information to the memory system regarding file-to-logical mapping of data prior to sending the data. The memory selects storage locations for the data based on the files to which the data belong.

Claims

1. A method of storing sectors of data from a plurality of files in a non-volatile memory array, sectors of each of the plurality of files mapped to a common logical address space by a host, comprising:

receiving file allocation information from the host that indicates a file to which a sector of host data is allocated;

subsequently receiving the sector of host data from the host for storage in the non-volatile memory array; and

subsequently storing the sector of host data in the non-volatile memory array in a physical location that is determined according to the file to which it is allocated according to the file allocation information from the host.

2. The method of claim 1 wherein the file allocation information from the host includes a sector of File Allocation Table information.

3. The method of claim 2 wherein the sector of host data is in a cluster of sectors and the sector of File Allocation Table information includes a File Allocation Table entry pointing to the cluster.

4. The method of claim 1 wherein the file allocation information from the host includes a sector of directory information containing an entry for the file.

5. The method of claim 1 wherein the sector is stored in an erase block that is dedicated for storage of sectors from the file.

6. The method of claim 5 wherein subsequent to storing the sector of host data, additional information is received from the host indicating that the sector is the last sector in the file and in response the file is closed and scheduled for reclaim.

7. The method of claim 1 further comprising receiving two or more identical sectors of control data from the host and in response carrying out reclaim operations while providing a status indicator to the host.

8. The method of claim 1 further comprising receiving two or more identical sectors of control data and in response preparing the memory array for a loss of power.

9. A method of storing sectors of host data from a host file in a non-volatile memory array having a metablock as the minimum unit of erase, sectors from the host file and other files mapped to a common logical address space, comprising:

receiving a first plurality of sectors of data of the host file, the first plurality of sectors occupying a first portion of the logical address space;

subsequently receiving a second plurality of sectors that are not of the host file, the second plurality of sectors occupying a second portion of the logical address space;

subsequently receiving a third plurality of sectors of the host file, the third plurality of sectors occupying a third portion of the logical address space, the first portion of the logical address space spaced apart from the third portion of the logical address space;

in response to information identifying the first and third portions of the logical address space as allocated to the host file, storing the first plurality of sectors and the third plurality of sectors in a first metablock of the memory array; and

storing the second plurality of sectors in a second metablock of the memory array.

10. The method of claim 9 wherein the first metablock is dedicated to storing data of the host file.

11. The method of claim 9 wherein the first and third portions of the logical address space are identified as allocated to the host file by directory and File Allocation Table sectors sent by the host.

12. The method of claim 9 wherein the second portion of the logical address space extends from the first portion of the logical address space to the third portion of the logical address space, further comprising:

prior to receiving the second plurality of sectors, receiving a directory sector indicating that a first cluster of the second plurality of sectors is not allocated to the host file.

13. The method of claim 12 further comprising:

prior to receiving the third plurality of sectors, receiving a File Allocation Table sector indicating that a first cluster of the third plurality of sectors is allocated to the host file.

14. A method of storing a host data file in a non-volatile memory array that has a metablock as the minimum unit of erase, comprising:

receiving a first plurality of sectors of data of the host data file, each of the first plurality of sectors having a logical address from a logical address space defined for the memory array, the plurality of sectors having logical addresses that occupy two or more discontinuous portions of the logical address space;

receiving a second plurality of sectors of data that are not of the host data file, each of the second plurality of sectors having a logical address from the logical address space, the second plurality of sectors received interspersed with the receipt of the first plurality of sectors; and

storing the data from the two or more discontinuous portions of the logical address space in a metablock that contains only data of the host data file.

15. The method of claim 14 further comprising receiving file allocation information regarding ones of the first plurality of sectors prior to receipt of the ones of the first plurality of sectors, the file allocation information identifying the ones of the first plurality of sectors as belonging to the host data file.

16. The method of claim 15 wherein the file allocation information is in the form of File Allocation Table and directory sectors.

17. The method of claim 14 further comprising receiving end of file information indicating the logical address of the end of the host data file and in response closing the host data file and scheduling the host data file for garbage collection.

18. A method of interfacing a memory system with a host that allocates sectors of host data files to a common logical address space, comprising:

the memory system receiving a plurality of sectors of host data from the host, the plurality of sectors allocated to a host file, the plurality of sectors of host data having logical addresses assigned by the host that are not contiguous; and

the memory system determining whether the plurality of sectors are allocated to the host file and, in response to determining that the plurality of sectors are allocated to the host file, the memory system storing the plurality of sectors in a portion of the memory array so that the plurality of sectors are located contiguously.

19. The method of claim 18 wherein the memory system determines whether ones of the plurality of sectors are allocated to the host file using file allocation information received from the host.

20. The method of claim 19 wherein the file allocation information that is received from the host includes one or more File Allocation Table sectors.

21. The method of claim 19 wherein the file allocation information that is received from the host includes one or more directory sectors.

22. The method of claim 18 wherein the memory system further determines that the end of the host file has been received and in response closes the file and schedules the file for garbage collection.