Enhancing lifetime and security of PCM-based main memory with start-gap wear leveling

Phase Change Memory (PCM) is an emerging memory technology that can increase main memory capacity in a cost-effective and power-efficient manner. However, PCM cells can endure only a maximum of 107 - 108 writes, making a PCM based system have a lifetime of only a few years under ideal conditions. Furthermore, we show that non-uniformity in writes to different cells reduces the achievable lifetime of PCM system by 20x. Writes to PCM cells can be made uniform with Wear-Leveling. Unfortunately, existing wear-leveling techniques require large storage tables and indirection, resulting in significant area and latency overheads.