Salvage the post life of solid state disk

The limited use lifetime is a significant drawback of the solid state disk (SSD). When the amount of bad blocks exceeds a threshold, the entire SSD is rendered non-functional as worn out. In this paper, we analysis the post life status of a SSD when it's worn out and explain the endurance characteristic induced by Flash charge trap. The real achievable endurance is much more than the threshold endurance defined by the Flash chip manufacturers. Two methods are proposed to salvage the post life. The results show that the SSD could be used as a read-only disk or with the life time extended by 2X at most 6% user capacity penalty.