面向新型3D NAND闪存的嵌入式存储系统优化方法研究

NAND flash memory has been widely used in removable storage devices such as USB flash drives and SD cards, mobile embedded systems such as smartphones and notebooks, and enterprise storage devices such as solid-state drives (SSDs). In order to further maintain the current pace of cost reduction for NAND flash memory, three-dimensional (3D) flash memory is emerging as a viable solution to solve the scaling problem in traditional planar NAND flash memory. Current 3D NAND flash memory structures can provide the scalable bit cost by fabricating more and more NAND strings in the Z-axis direction. Multiple layers are stacked to provide ultra high density storage devices. However, current NAND flash memory optimization techniques focus primarily on the two-dimensional planar NAND flash memory. How to fully utilize the system structure and hardware implementation of emerging 3D NAND flash memory, remains an open problem...In this project, we aim to enhance the reliability and optimize I/O performance for embedded storage systems with 3D NAND flash memory. To solve the reliability problem in 3D NAND flash memory, a novel address mapping strategy is proposed to improve the reliability for metadata. We also present an application-specific distributed garbage collection strategy and an application-specific wear-leveling strategy to optimize the average response time. Based on these strategies, a cross-layer data management framework is designed to jointly optimize different system software components in 3D NAND flash architecture, such as buffer management, file system, flash translation layer, and memory technology device. The theoretical frameworks and optimization techniques generated from this project can provide new directions for the design of embedded storage systems with 3D NAND flash memory.

研究面向新型3D NAND闪存的嵌入式系统优化技术有着巨大的应用价值。NAND闪存的年销售额已超过1600亿元。作为最新一代的闪存技术，3D NAND通过三维方向堆叠闪存来实现存储容量成倍的快速增长。然而，现有的闪存管理技术都是应用于传统二维平面NAND闪存。在嵌入式系统中，如何设计闪存管理技术来有效利用3D NAND在存储机制上的新变化，是亟待解决的问题。本项目结合读写性能、数据完整性等关键指标，开展面向3D NAND闪存的系统软件优化技术研究。本项目的研究成果将为3D NAND闪存的系统软件管理方法提供新思路，为其在嵌入式系统中的应用提供技术支撑。

研究面向新型3D NAND闪存的嵌入式系统优化技术有着巨大的应用价值。本项目从嵌入式系统体系结构及系统软件的角度，研究提升3D NAND 闪存系统可靠性的优化方法。本项目针对3D NAND 闪存在存储机制上的特性，设计了一套嵌入式存储系统中系统软件的优化方法。实验结果表明，本项目的优化方法可以有效提升3D NAND 闪存系统可靠性，以及有效提高存储系统读写性能、延长使用寿命。本项目的主要考核指标是论文。在项目执行期内拟发表论文5篇，实际发表论文24篇，其中SCI索引论文17篇、EI索引论文24篇。研究成果包括中国计算机学会推荐A类国际期刊或论文10篇、B类论文8篇、C类论文3篇，IEEE Transactions论文15篇，均属于本领域内的高水平论文。发表的论文中，第一作者论文14篇、通讯作者论文5篇、第二作者论文3篇。其中一篇论文获得CCF-B类会议2017年嵌入式系统编程语言、编译器及工具国际会议（LCTES 2017）的唯一最佳论文奖。也是中国大陆高校及研究机构首次以第一作者单位获得该会议的最佳论文奖。本项目拟申请发明专利2项。实际申请发明专利14项、其中授权国内发明专利2项、国际PCT专利3项。在国家自然科学基金项目的支持下，顺利完成了项目既定的考核指标。本项目的研发将为3D NAND闪存的系统软件管理方法提供新思路，为其在嵌入式系统中的应用提供技术支撑。