CIF: Small: Coding for Non-Volatile Memories

非易失性数据存储设备，特别是基于NAND闪存和新兴相变存储器（PCM）技术的非易失性数据存储设备，正在彻底改变我们访问和操作信息的方式。与磁性硬盘驱动器相比，它们有许多吸引人的特点，包括紧凑、抗冲击和更快的数据访问。闪存现在在便携式消费电子产品中是首选，高性能固态驱动器（ssd）正在被引入移动计算、企业存储、数据仓库和数据密集型计算应用中。因此，对这些非易失性存储器技术的改进、开发和扩大商业用途的兴趣激增。另一方面，这些技术在设备可靠性、耐用性和能源效率方面提出了重大挑战。这些挑战可以部分地通过创新的编码和数据处理技术来克服，这也是本研究项目的主题。具体来说，解决的问题包括：(1)使用一次写入存储器（WOM）编码技术为单级单元（SLC）闪存设计高效，容错的重写代码；(2)设计了用于多级单元（MLC）闪存的非二进制重写码，以及允许非对称单元级转换和写入错误的码；(3)编码技术的发展，减轻了PCMs中热量积累的影响；(4)卡槽pcm纠错码的设计。研究内容包括闪存和PCM信道模型的信息论分析、新编码方案的开发以及系统性能评估。该项目的一个独特之处在于使用了加州大学圣地亚哥分校非易失性系统实验室的设施，为设备表征和新编码技术和架构的经验性能比较提供了一个实验平台。

Non-volatile data storage devices, particularly those based upon NAND flash memory and emerging phase-change memory (PCM) technologies, are revolutionizing the way we access and manipulate information. They have many attractive features compared to magnetic hard disk drives, including their compactness, shock resistance, and faster data access. Flash memory is now preferred in portable consumer electronics, and high performance solid-state drives (SSDs) are being introduced in mobile computing, enterprise storage, data warehousing, and data-intensive computing applications. Accordingly, there is a surge in interest in the refinement, development, and expanded commercial use of these non-volatile memory technologies. On the other hand, these technologies present major challenges in the areas of device reliability, endurance, and energy efficiency. These challenges can be overcome, in part, through innovative coding and data handling techniques, which is the subject of this research project. Specifically, the problems addressed include: (1) the design of efficient, error-resilient rewriting codes for single-level cell (SLC) flash memories using write-once memory (WOM) coding techniques; (2) the design of non-binary rewriting codes for multi-level cell (MLC) flash memories, as well as codes that tolerate asymmetric cell-level transitions and writing errors; (3) the development of coding techniques that mitigate the effects of heat accumulation in PCMs; and (4) the design of error-correcting codes for PCMs with stuck cells.The research involves the information-theoretic analysis of flash memory and PCM channel models, the development of novel coding schemes, and system performance evaluation. A unique aspect of the project is the use of the facilities of the Non-Volatile Systems Laboratory at UC San Diego, providing an experimental platform for device characterization and empirical performance comparisons of new coding techniques and architectures.