Computer Architecture and System Laboratory


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

(single PI, funded by the National Science Foundation under grant CNS-1320738, $440,727, 10/2013 ~ 09/2017)


Overview

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.


Publications

    Wei Wang, Wen Pan, Tao Xie, and Deng Zhou, "How Many MLCs Should Impersonate SLCs to Optimize SSD Performance?" The 2nd International Symposium on Memory Systems (MEMSYS 2016), Washington DC, USA, October 3-6, 2016. [At-a-Glance] [PDF]

    Deng Zhou, Wen Pan, Wei Wang, and Tao Xie, "I/O Characteristics of Smartphone Applications and Their Implications for eMMC Design," The 11th IEEE International Symposium on Workload Characterization (IISWC 2015), Atlanta,, USA, October 4-6, 2015. (source code and the traces will be provided upon email request). [At-a-Glance] [PDF]

    Wei Wang, Tao Xie, "PCFTL: A Plane-Centric Flash Translation Layer Utilizing Copy-Back Operations," IEEE Transactions on Parallel and Distributed Systems, Vol. 26, No. 12, pp. 3420-3432, December 2015. [PDF]

    Cailiang Xu, Wei Wang, Deng Zhou, and Tao Xie, "An SSD-HDD Integrated Storage Architecture for Write-Once-Read-Once Applications on Clusters," The 17th IEEE International Conference on Cluster Computing (Cluster 2015, Short Paper), Chicago, USA, September 8-11, 2015. [PDF]

    Wei Wang, Tao Xie, Antoine Khoueir, and Youngpil Kim, "Reducing MLC Flash Memory Retention Errors through Programming Initial Step Only," The 31st International Conference on Massive Storage Systems and Technologies (MSST 2015, Research Track), Santa Clara, USA, May 30-June 5, 2015. [At-a-Glance] [PDF]

    Wei Wang, Deng Zhou, and Tao Xie, "An Embedded Storage Framework Abstracting Each Raw Flash Device as An MTD," The 8th ACM International Systems and Storage Conference (SYSTOR 2015, Full Paper), Haifa, Israel, May 26-28, 2015. [At-a-Glance] [PDF]


People

Tao Xie

Ph.D. students: Wen Pan, Xiaojia Song, Deng Zhou, Wei Wang

Undergraduate students: Kyle Sablan