Differentiated space allocation for wear leveling on phase-change memory-based storage device

Phase-change memory (PCM) is the best candidate for the storage device of next-generation mobile consumer electronics. PCM has the potential to replace NAND flash memory, due to its non-volatility, in-place programmability, and low power consumption. Even though the lifetime of PCM is longer than that of flash memory, wear leveling is still required to cope with the non-uniformity of storage workload or malicious attack. In this paper, a novel wear-leveling algorithm for PCM storage is proposed, where more physical pages are allocated to frequently updated logical pages, to balance the wear counts of PCM cells. In comparison with the previous techniques, the proposed algorithm improved the lifetime of PCM by at maximum 14 times and on average 8 times¹.