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. We propose Start-Gap, a simple, novel, and effective wear-leveling technique that uses only two registers. By combining Start-Gap with simple address-space randomization techniques we show that the achievable lifetime of the baseline 16GB PCM-based system is boosted from 5% (with no wear-leveling) to 97% of the theoretical maximum, while incurring a total storage o...

• Type: Conference
• Year: 2009
• Where: MICRO
• Authors: Moinuddin K. Qureshi, John Karidis, Michele Franceschini, Vijayalakshmi Srinivasan, Luis Lastras, Bülent Abali
• Keywords: Achievable Lifetime, Hardware, MICRO 2009, PCM Cells, Phase Change Memory