Managing a LBA interface in a direct data file memory system

• US 8,166,267 B2
• Filed: 12/26/2006
• Issued: 04/24/2012
• 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): YU, JAE UN
• Application Number:
  US11/616,226
• Publication Number:
  US 20080155227A1
• Time in Patent Office: 1,946 Days
• Field of Search: 711/165, 711/103, 711/161, 711/162, 711/203
• US Class Current: 711/165
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control

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 assigning addresses to data of file objects within a continuous logical address space, comprising:

divide the continuous logical address space into logical blocks of addresses, said logical blocks having a capacity, maintain at least one list including logical blocks that individually contain addresses assigned to an amount of valid data less than a the capacity of the logical blocks, select a logical block from said at least one list, copy the addresses assigned to valid data from the selected logical block into another logical block, and thereafter utilize the selected logical block for storing addresses for other data, wherein selecting a logical block includes selecting the logical block from said at least one list that has the least amount of valid data with assigned addresses in such logical block relative to the amount of valid data with assigned addresses in other logical blocks on the list.

2. The method of claim 1, wherein selecting a logical block from said at least one list additionally includes selecting the logical block from said at least one list on the basis of an amount of unused storage capacity therein relative to the amount of unused storage capacity in other logical blocks on said at least one list.

3. A method of managing a continuous logical address space at an interface, comprising:

dividing the logical address space into logical blocks of distinct addresses,

initially designating addresses of data of individual file objects to be within certain first logical block of the logical blocks, and

thereafter redesignating addresses for at least some of the data of at least one of the individual file objects in at least one second logical block different than the first logical block initially designated, so that the redesignated addresses of said at least some of the data of at least one of the individual file objects in the second logical block are different from the initially designating addresses within the first logical block.

4. The method of claim 3, wherein the redesignating addresses includes doing so without changing said at least some of the data of at least one of the individual file objects.