Global Wear Leveling

More and more industrial PCs and embedded systems utilize NAND flash storages for both OS and data storage applications. Some of these applications use intensive programming and erasure operations which raises concerns about NAND Flash storage's life expectancy. NAND Flash storages are limited to a finite number of Program/Erase (PE) cycles. An embedded system's life expectancy is tied directly to how the flash storage is used and the number of PE cycles guaranteed by the flash storage device. The biggest concern with flash storage life expectancy, or endurance, is when data is constantly being written back and forth to certain memory units, creating more and more bad blocks and it will eventually "wear" out the storage.

Global Wear Leveling would even the erase count of all blocks, effectively “wear level” the entire SSD to extend the life expectancy.

• Global Wear Leveling treats and manages all NAND flash components in ONE drive as one unified memory management unit
• Global Wear Leveling maps host device's logical addresses into NAND flash physical addresses equally and randomly
• Endurance will be further improved when the total density increases (more spare space for spare blocks)

 

 

The "older" dynamic wear algorithm only guarantees that program and erase cycles will be evenly distributed throughout all the blocks within the same memory unit. The more advanced Global Wear Leveling will not only distribute/replace blocks with high PE cycles (in purple) with unused blocks (in blue) from spare block, but also replace reserved blocks with low PE cycles across the whole drive.