DREAM: Data Representation Aware of Damage to Extend the Lifetime of MLC NAND Flash Memory

Authors: 

Ting Ye, Wuhan National Laboratory for Optoelectronics, Huazhong University of Sci. and Tech., China; Shenggang Wan, School of Computer Science and Technology, Huazhong University of Sci. and Tech., China; Xubin He, Department of Computer and Information Sciences, Temple University, USA; Weijun Xiao, Virginia Commonwealth University, USA; Changsheng Xie, Wuhan National Laboratory for Optoelectronics, Huazhong University of Sci. and Tech., China

Abstract: 

MLC NAND flash memory uses the voltages of the memory cells to represent bits. High voltages cause much more damage on the cells than low voltages. The free space that need not store bits is leveraged to reduce the usage of those high voltages and thus extend the lifetime of the MLC memory. However, limited by the conventional data representation rule that represents bits by the voltage of one single cell, the high voltages are still used in a high probability. To fully explore the potential of the free space on reducing the usage of high voltages, we propose a novel data representation aware of damage, named DREAM. DREAM uses the voltage combinations of multiple cells instead of the voltage of one single cell to represent bits. It enables to represent the same bits through flexibly replacing the high voltages in some cells with the low voltages in other cells when free space is available. Hence, high voltages which cause more damage are less used and the lifetime of the MLC memory is extended. Theoretical analysis results demonstrate the effectiveness and efficiency of DREAM.

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BibTeX
@inproceedings {216868,
author = {Ting Ye and Shenggang Wan and Xubin He and Weijun Xiao and Changsheng Xie},
title = {{DREAM}: Data Representation Aware of Damage to Extend the Lifetime of {MLC} {NAND} Flash Memory},
booktitle = {10th {USENIX} Workshop on Hot Topics in Storage and File Systems (HotStorage 18)},
year = {2018},
address = {Boston, MA},
url = {https://www.usenix.org/conference/hotstorage18/presentation/ye},
publisher = {{USENIX} Association},
}