Method for Enhancing Life Cycle of Memory

• US 20080183947A1
• Filed: 01/30/2007
• Published: 07/31/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: Skymedi Corporation
• Original Assignee: Skymedi Corporation
• Inventors: Shone, Fuja, Tai, Shih-Chieh
• Granted Patent: US 8,140,737 B2
• 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 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7211 Wear leveling

Abstract

A hierarchical mechanism for preventing concentrated wear on single physical block or a specific set of physical blocks in the physical memory is proposed. The logical blocks mapping to the physical blocks in the physical memory are classified into two different levels for implicitly representing the modification times of the physical blocks. A modify count and a maximum modify count are further included for counting the modification times in a single process of the hierarchical mechanism and for limiting the modification times in single process, leading to the probabilities of all the physical blocks being modified in the physical memory being balanced. The breakdown of the physical memory caused by the breakdown of a specific set of physical blocks or single physical block is thus prevented.

Claims

1. A method for enhancing a life cycle of memory comprising:

updating a content of a data block and moving the data block to a free block;

updating a level of the data block and updating a modify count of the memory in response to the movement of the data block when the modify count has not reach a predetermined value;

when the modify count reaches the predetermined value, updating the level of remaining data blocks whose level is different from other data blocks'"'"' level and moving the remaining data blocks to free blocks without updating contents of the remaining data blocks; and

when all data blocks reach a same level, resetting the modify count.

2. The method of claim 1 wherein updating the level of the remaining data blocks is keeping on updating the level of the remaining data blocks until a current level is reached.

3. The method of claim 1 wherein updating a level of the data block and updating a modify count of the memory in response to the movement of the data block when the modify count does not reach the predetermined value is keeping on increasing a level of the data block until a current level is reached and increasing a modify count of the memory in response to the movement of the data block when the modify count is smaller than the predetermined value.

4. The method of claim 3 wherein when the modify count reaches the predetermined value, updating the level of remaining data blocks whose level is different from other data blocks'"'"' level and moving the remaining data blocks to free blocks without updating contents of the remaining data blocks is when the modify count reaches the predetermined value, increasing the level of remaining data blocks whose level is smaller than other data blocks'"'"' level and moving the remaining data blocks to free blocks without updating contents of the remaining data blocks.

5. A method for enhancing a life cycle of memory, the method comprising:

modifying data in a logical block of virtual memory;

increasing a modify count;

storing the modified data in a free block of physical memory and associating the free block with the logical block; and

if the modify count is greater than a predetermined value, swapping blocks of physical memory associated with each unmodified logical block with a free block of physical memory.