Research Of Hybrid Memory System Based On Phase Change Memory

With high-speed development of informantion technology, computer realm enters data-centric big data era. Rapid growth of data scale brings opportunities and challenges for computer storage system. Traditional memory based on DRAM almost reaches limitation when meeting problems of system stability, data reliability and energy consumption caused by shrinking craft size. Phase change memory(PCM) has advantages of high storage density and low power consumption. Furthermore, it is non-volatile, anti-radiation and anti-interference, and its performance is close to DRAM. It offers a new idea to research and design of storage system.To settle the difficulties of current memory technology, hybrid memory system based on PCM has been proposed, which explores advantages and overcomes limitations of performance and lifetime of PCM, designs system architecture of hybrid memory and request scheduling flow, deploys memory address mapping and wear leveling policy, and thus accomplishes a PCM-based hybrid memory system solution. Memory controller specific to LPDDR2 PCM chip of Micron has been designed, and memory protocol architecture of PCM based on AXI bus has been studied. PCM memory card has been designed, which utilizes embedded development kit, adopts the form of coupling sub card and carrier card with CPU and then realizes a PCM-based hybrid memory prototype.Tests, analysis and verification about aboved hybrid memory system have been conducted. From experimental results we know there exists a definite gap in performance between hybrid memory system based on PCM and traditional DRAM memory system. However, hybrid system has such strong scalability that to a certain degree relieves difficulties current memory system faces. Simultaneously, realized hybrid prototype platform alleviates the awkwardness of no available hardware for current researches, discusses the method of PCM device acting as memory and confirms its viability.