MAND Flash Wear Leveling Based on Mutil-Threshold

Yaffs2, special to NAND Flash, still exits defect aiming at wear leveling.A static wear-leveling algorithm based on Yaffs2 is designed in this paper, considering the contradiction between wear-leveling and garbage collection.Firstly, Improve retrieve block selection mechanism: choose the block for recycle whose the value of benifit/cost falling to the target range according to the formula (1), and its erasure number is biggest; Secondly, allocation free page whose erasure number is smallest to new data and whose erasure number is biggest to cold data in line of orderly two-way linked list; Last, introduce hot and cold data separation strategy orienting to hot and cold data coexists in a block.The experimental results show that the algorithm prolongs NAND lifetime nearly four times at the expense of 4.05% additional erasure number.