Analysis on retention relaxation effects for solid state drives

Recently, supporting two write modes for NAND flash memory was proposed to utilize the short retention time of written data. It performs a shallow write, which is faster than the existing NAND write, for the host write requests, based on the assumption that their retention time will be short. If the retention expires, the according data are re-written in slow write mode to guarantee a long retention time. This work analyzes the advantages of the retention relaxation, the source of the performance improvement, and the possible disadvantages.