基于相变存储器的存储系统与技术综述

Summary of Storage System and Technology Based on Phase Change Memory

随着处理器和存储器之间性能差距的不断增大,"存储墙"问题日益突出,但传统DRAM器件的集成度已接近极限,能耗问题也已成为瓶颈,如何设计扎实有效的存储架构解决存储墙问题已成为必须面对的挑战.近年来,以相变存储器(phase change memory,PCM)为代表的新型存储器件因其高集成度、低功耗的特点而受到了国内外研究者的广泛关注.特别地,相变存储器因其非易失性及字节寻址的特性而同时具备主存和外存的特点,在其影响下,主存和外存之间的界限正在变得模糊,将对未来的存储体系结构带来重大变化.重点讨论了基于PCM构建主存的结构,分析了其构建主存中的写优化技术、磨损均衡技术、硬件纠错技术、坏块重用技术、软件优化等关键问题,然后讨论了PCM在外存储系统的应用研究以及其对外存储体系结构和系统设计带来的影响.最后给出了PCM在存储系统中的应用研究展望.

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.