What Is Wear Levelling in NAND Flash?

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The NAND flash technology comes with several benefits, but there are some drawbacks as well. However, we can overcome those by selecting reliable brands like KingSpec and implementing the right wear leveling.

What is wear leveling in NAND flash?

Wear leveling is the technique that extends the lifespan of your NAND flash device. These serve for a specific time. You can write on virtual blocks repeatedly. After some time, these blocks become technically useless, and that section of the NAND flash also becomes useless. With wear leveling, the life of the NAND flash can be increased by distributing program/erase cycles evenly on the flash memory.

It is done using software that makes one physical block of memory efficient enough so we can reliably write data on it up to 100,000 times and erase it up to 10000 times. However, we must select the algorithm for wear leveling according to the application of NAND flash.

For instance, if it is used for a write-intensive application, the wear leveling algorithm must be implemented to monitor the write cycles and spread them evenly per block. That is how equal usage of physical space on the NAND flash can be achieved, and thus life can be increased.


The impact of wear leveling on NAND

Depending on the software monitoring and file system, the implementation of wear leveling also differs, for example. In a FAT file system, the erase cycles on a physical block are frequent, and the write operations imply the same physical block. So, the lifespan of NAND flash decreases.

The lifespan can be increased by implementing wear leveling on the NAND flash. It ensures that an application efficiently writes on virtual blocks. Even if the same virtual blocks are used again, the PROGRAM/Erase cycles are distributed over NAND flash storage. Thus, the lifespan significantly increases.

Different wear leveling algorithms.

Wear leveling of the NAND flash storage is directly proportional to the block aging table. It stores information about the blocks that have been erased within a specific time. So, to implement wear leveling, we can use 2 algorithms which are:

Dynamic wear leveling

Dynamic wear leveling means that new data will be programmed in the free blocks present among blocks that store the user's data. These blocks are selected according to the ones with the least WIRTE/ERASE cycles.

Static wear leveling

Things are a little different with static wear leveling. Here the content of blocks that store static data like code is copied to other blocks. The original data is stored on other blocks, and the original block is used for storing frequently changed data. This algorithm is most effective when the difference between minimum and maximum WRITE/ERASE cycles meets the threshold limit. Thus, it helps maintain a constant mean age of physical NAND flash memory blocks.

Learn which KingSpec NAND flash would work the best for your use case.

Wear leveling has a huge role in shaping your experience with a NAND flash. However, it is not the alone factor affecting your usability. For the best experience, you must choose the right brands, like KingSpec, for much better performance and lifespan.


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