R&D: Survey on Flash-Memory Storage Systems, Host-Side Perspective

ACM Transactions on Storage has published an article written by Jalil Boukhobza, ENSTA, Institut Polytechnique de Paris and Academia Sinica, Palaiseau, France, Pierre Olivier, The University of Manchester, Oxford, United Kingdom of Great Britain and Northern Ireland, Wen Sheng Lim, Deparment of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan, Liang-Chi Chen, National Taiwan University, Taipei, Taiwan, Yun-Shan Hsieh, National Cheng Kung University, Tainan, Taiwan, Shin-Ting Wu, Academia Sinica, Taipei, Taiwan, Chien-Chung Ho, College of Computer Science Information Engineering, National Cheng Kung University, Tainan City, Taiwan, Po-Chun Huang, National Yang Ming Chiao Tung University, Hsinchu Taiwan, and Yuan-Hao Chang, Institute of Information Science, Academia Sinica, Taipei, Taiwan.

Abstract: “NAND flash memory has become the dominant storage media choice in a vast majority of application scenarios. Compared to mechanical hard disks, flash offers better access performance, energy efficiency, and shock resistance. However, the unique hardware peculiarities of this technology require dedicated facilities to manage the flash space and data. The implementation of flash management facilities has alternatively been realized either at the device or host computer level. Managing flash on the device side eases integration/compatibility and increases performance in certain scenarios. However, the limited computing resources inherent to devices and the lack of higher-level file system/application information make these solutions suboptimal in many situations. Managing flash on the host allows leveraging its abundant resources, and host-side knowledge such as data access patterns can be exploited to optimize flash management, at the cost of increased host-side complexity. The pros and cons of each approach also led to the appearance of hybrid, cross-layer solutions, enabling the collaboration of different layers of the storage stack. Recently, the pressure on modern storage systems requires that an increasing amount of flash management responsibilities is offloaded to the host, and the development of application-specific cross layer solutions: in that context, it is crucial to review these developments. In this paper, we make a comprehensive survey of the host-side management technologies of flash memory, application-/system-level flash-friendly designs, and emergent applications based on flash memory.“