Increasing PCM Lifetime by Using Pipelined Pseudo-Random Encoding Algorithm

Phase change memory (PCM) is a promising technique due to its low static power, non-volatility, and density potential. However, the low endurance remains as the key problem to be solved before it can be widely used in practice. Generally, minimizing modified bits in write operation by writing the different bits, is an effective method to extend the lifetime of PCM. But it’s still challenging to reach the minimum without causing significant slowdown of read/write operations. To this end, we propose FEBRE: A fast and efficient bit-flipping reduction technique to extend PCM lifetime. The key idea of our method is to design and use a novel one-to-many parallel mapping before differential write stage. Specifically, FEBRE employs a new data encoding method to generate multiple highly random distributed encoded vectors from one writing data item, which thus increases the possibility of identifying the nearest one to stored data in those vectors. The other contribution of our technique is a pipelined pseudo-random encoding algorithm (PPREA). The new algorithm reduces writing overhead because it is able to accelerate the procedure of the one-to-many mapping. The experiment shows that our technique, compared with PRES, can reduce bit flips by 5.31% on average, and improve the encodingdecoding speed by 2.29x and 45%, respectively.