Use of a direct data file system with a continuous logical address space interface and control of file address storage in logical blocks

• US 8,046,522 B2
• Filed: 12/26/2006
• Issued: 10/25/2011
• Est. Priority Date: 12/26/2006
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Sinclair, Alan W., Wright, Barry
• Primary Examiner(s): Thomas; Shane M
• Application Number:
  US11/616,242
• Publication Number:
  US 20080155178A1
• Time in Patent Office: 1,764 Days
• Field of Search: 711/103
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies

Abstract

Data files are assigned addresses within one or more logical blocks of a continuous logical address space interface (LBA interface) of a usual type of flash memory system with physical memory cell blocks. This assignment may be done by the host device which typically, but not necessarily, generates the data files. The number of logical blocks containing data of any one file is controlled in a manner that reduces the amount of fragmentation of file data within the physical memory blocks, thereby to maintain good memory performance. The host may configure the logical blocks of the address space in response to learning the physical characteristics of a memory to which it is connected.

Claims

1. A method of identifying data of file objects within a system, comprising:

maintaining a system logical address space that is divided into logical blocks,

assigning unique addresses to individual ones of the file objects within one or more of the logical blocks, wherein the logical blocks may individually contain addresses of more than one file object, and

limiting the number of logical blocks to which an individual file object is assigned that also contain an address of a second file object.

2. The method of claim 1, additionally comprising:

carrying out the method in a host system that additionally provides the data of the file objects and utilizes the system logical address space at an external interface adapted to be connected with a memory system.

3. The method of claim 1, additionally comprising:

carrying out the method in a memory system that additionally receives the data of the file objects from an external source and utilizes the system logical address space that is within the memory system as an interface with non-volatile data storage media.

4. The method of claim 1, additionally comprising:

carrying out the method in a processing unit that is adapted to be removably connected through a first interface with a host that supplies the data file objects and is adapted to be removably connected with a memory system that utilizes the system logical address space at a second interface with the processing unit.

5. The method of any one of claims 1-4, wherein limiting the number of logical blocks includes limiting the number of logical blocks to which an address of an individual data file object is written that also contain an address of a second file object to a predetermined maximum number.

6. The method of claim 5, wherein the predetermined maximum number is two.

7. A method of a host system transferring data of file objects through an interface adapted for connection with a non-volatile memory system of a type having blocks of memory cells that are erasable together prior to being reprogrammed, comprising:

maintaining at the interface a logical address space that is divided into logical blocks, and

designating addresses of data within individual ones of the file objects within one or more of the logical blocks in a manner that the logical blocks may individually contain addresses of more than one file object but which limits to less than at least one preset limit a number of logical blocks that are only partially filled with an address of an individual file object such that an address of one or more other file objects are or may be written into the partially filled blocks.

8. The method of claim 7, additionally comprising:

configuring the sizes of the logical blocks of the logical address space to individually have the same data storage capacity as the individual blocks of memory cells of a memory system with which the host system is adapted to be connected.

9. The method of claim 7, wherein the addresses of data of the individual file objects within one or more of the logical blocks are designated upon the host sending data of the file objects through the interface.

10. A method of storing data of file objects in a non-volatile memory system having blocks of memory cells that are erasable together prior to being re-programmed with the data, wherein:

a logical address space is divided into logical blocks that individually have at least one characteristic corresponding to that of the individual memory cell blocks,

assigning addresses of data of individual file objects within one or more of the logical blocks, wherein the logical blocks may individually contain addresses of data of more than one file object but the number of logical blocks containing an address of a particular individual file object plus an address of another file object is limited, and

addresses of the logical blocks are mapped within the memory system to addresses of memory cell blocks.

11. The method of claim 10, wherein assigning addresses to data of the particular file object includes limiting the number of logical blocks that are only partially filled with an address of the particular file object to a predetermined number.

12. The method of claim 11, wherein the predetermined number is two.

13. The method of claim 10, wherein the at least one corresponding characteristic includes a data storage capacity of the individual logical blocks being the same as that of the individual memory cell blocks.

14. The method of claim 10, wherein the at least one corresponding characteristic includes:

the data storage capacity of the individual logical blocks being the same as that of the individual memory cell blocks,

the individual logical blocks being divided into multiple pages for writing data therein that have the same data storage capacity as individual multiple pages of the memory cell blocks, and

the lowest page addresses of the individual logical blocks being mapped into the first pages of the individual memory cell blocks.

15. A method of a host system transferring data of file objects through an interface adapted for connection with a non-volatile memory system of a type having units of memory cells that are erasable together prior to being reprogrammed, comprising:

maintaining at the interface a logical address space that is divided into logical blocks,

designating a set of a plurality of logical block types in terms of a structure of file data addressed within individual blocks so designated,

designating a set of a plurality of permitted file states in terms of a combination of types of one or more logical blocks in which addresses of individual files so designated are stored,

maintaining a record of the file states of individual data files addressed within the logical blocks, and

designating addresses of data for an individual file to a type of logical block selected according to the current state of the individual file in the record.

16. The method of claim 15, wherein the designated plurality of logical block types includes a first plurality of types in which an address of only one file are stored in a single logical block and a second plurality of types in which addresses of two or more files are stored in a single logical block, and wherein the permitted file states limit a maximum number of blocks of the second plurality of types to which addresses of a single one of the files may be designated.