CSR: Small: A Device-Array Based Flash Storage System for Emerging Data-Intensive and Mission-Critical Mobile Applications: from Architecture Redesign to New File System

闪存制造商正在积极扩大NAND闪存密度，以便使用MLC（多级单元）或TLC（三级单元）技术来增加容量并降低每千兆字节的成本。然而，其他指标，如可靠性，耐力和性能都在下降。因此，在越来越大但劣质的NAND闪存设备上开发高性能和高可靠性的嵌入式闪存存储系统已变得不可或缺且具有挑战性。利用从硬件重新架构到软件重新设计的整体方法，该项目设计、实施和评估一种新的闪存存储系统，用于新兴和未来的数据密集型移动的应用，如无线医疗保健和体育直播。特别是，该项目将用多设备阵列架构取代现有的单设备硬件组织。接下来，这个项目将开发一个新的闪存文件系统，可以并行访问多个闪存设备。此外，还将开发一系列新技术，包括垃圾收集方法、磨损均衡机制、ECC保护和数据恢复方案。最后，一个硬件原型，可以经验性地评估新的闪存设备阵列架构和所有的软件模块将被建立。新的闪存文件系统，包括源代码和文档，所有新技术，和硬件原型，这个项目的成果，将向公众发布。该项目还将通过让学生接触移动的存储系统领域的技术和科学基础来促进教学、学习和培训。

Flash memory manufactures are aggressively scaling up NAND flash density in order to increase capacity and reduce the cost per gigabyte using either MLC (multi-level cell) or TLC (triple level cell) technologies. However, other metrics like reliability, endurance, and performance are all declining. As a result, developing a high-performance and highly reliable embedded flash storage system on top of increasingly larger but inferior NAND flash memory devices has become both indispensable and challenging. Utilizing a holistic approach from hardware re-architecting to software redesign, this project designs, implements, and evaluates a new flash storage system for emerging and future data-intensive mobile applications such as wireless healthcare and live sport broadcast. In particular, this project will replace the existing single-device hardware organization with a multiple-device array architecture. Next, this project will develop a new flash file system that can access multiple flash memory devices in parallel. Also, a wide spectrum of new techniques including garbage collection method, wear levelling mechanism, ECC protection, and data recovery scheme will be developed. Finally, a hardware prototype that can empirically evaluate the new flash device array architecture and all software modules will be built. The new flash file system including source code and documents, all new techniques, and the hardware prototype, the outcomes of this project, will be released to the public. This project will also promote teaching, learning, and training by exposing students to technological and scientific underpinnings in the field of mobile storage systems.