Abstract: With the increasing of performance gap between CPU and memory, the “memory wall” problem becomes more and more prominent. In order to bridge the gap, many DRAM based solutions are proposed. However, the DRAM is approaching the bottleneck in density and energy cost. How to design a practical memory architecture to settle this problem is becoming more and more prominent. Recent years, phase change memory (PCM) has gained great attention of researchers from domestic and abroad for its high density and low energy cost. And especially, its non-volatility and byte addressable feature are blurring the difference of memory and storage, which can bring significant changes for future memory architecture. This paper mainly discusses the architecture of main memory based on PCM and related technology about tolerating slow writes, ware leveling, erasure codes, reuses of failed blocks and software optimizing. And this paper also discusses the application of PCM in storage system and the affects on the design of storage architecture and computer system. After the discussion, the research works are summarized and the possible research directions are pointed out.

Key words: new storage device, non-volatile memory, PCM, main memory, external storage