基于区块结构的Nand Flash存储系统闪存转换层研究

发布时间：2018-02-03 16:53

本文关键词： 闪存闪存转换层地址映射垃圾回收缓冲区置换算法　出处：《中国地质大学（北京）》2013年硕士论文　论文类型：学位论文

【摘要】：近年来，由于闪存技术的飞速发展，以及闪存本身固有的非易失性、可以高速运行、体积小、耗能低、抗震动性及可靠性高的特点，，使得闪存成为嵌入式系统中的首选存储介质，并为企业级存储系统开辟了新的前景。但是现有磁盘存储技术无法直接运用在闪存存储设备上。因此，研究一种适合闪存的高效存储管理技术，将具有极其重要的意义。在本论文中，首先总结了闪存存储管理领域已存在的方案，分析出闪存管理的关键要素，并在地址映射、垃圾回收和缓冲区置换算法这几个方面进行了探索研究，提出了对应的解决方案。本论文主要包含以下方面： 1.提出了一种新颖的地址映射算法，该算法基于区块切换结构，简称为ZFTL。ZFTL是一种创新的纯页映射的闪存转换层，该方案把整个闪存芯片划分成多个区域加以管理。由于ZFTL方案每次只是把当前请求对应区块的地址信息缓存到内存中，所以明显地降低了内存开销，对集成度较高的内存具有很好的扩展性。 2.提出了一种二级缓冲机制，该机制基于访问模式选择算法。充分利用闪存工作时的时间及空间局部性，极大地减少了地址转换所造成的开销。通过选择性地对映射关系加以缓存，ZFTL可以高效地利用有限的内存资源，显著地提升了缓冲区的命中率，并减少了系统的响应时间。 3.本论文还引入了一个用于验证闪存转换层算法的仿真平台。该仿真平台以FlashSim为基础，对它进行了二次加工添加了ZFTL算法，实现了三种经典FTL算法：页映射、DFTL和FAST。本论文最后的仿真步骤使用了从现实生活中获取的访问请求作为输入源，在不同工作负载下对论文中的四种FTL算法进行了仿真，经过对比加以分析，ZFTL方案优势明显，在实际应用中将极大地提高NAND Flash性能并降低成本。
[Abstract]:In recent years, due to the rapid development of the technology of flash memory and flash memory inherent in non-volatile, high speed, small volume, low power consumption, high reliability and anti vibration characteristics, has become the first choice of flash storage medium in embedded system, and open up new prospects for the enterprise but the existing storage system. Disk storage technology can not be directly used in the flash memory storage device. Therefore, a study of flash memory efficient storage management technology, will have the extremely vital significance.
In this paper, firstly summarizes the existing field of flash memory management scheme, analyzes the key elements of storage management, and address mapping, researches the garbage collection and buffer replacement algorithm of these aspects, puts forward corresponding solutions. This paper mainly includes the following aspects:
1. we propose a novel address mapping algorithm, the algorithm based on block switching structure, referred to as ZFTL.ZFTL is pure page mapping of an innovative flash translation layer, the scheme of the flash chip is divided into a plurality of regional management. Because the ZFTL program every time just to address information corresponding to the current request block cache memory so, significantly reduces the memory overhead, has good scalability for high-density memory.
2. proposed a two level buffer mechanism, the mechanism of access mode selection algorithm based on full use of flash when the time and spatial locality, greatly reduces the overhead caused by address translation. By selectively cached mappings, ZFTL can efficiently use the limited memory resources, and improve the the buffer hit ratio, and reduces the response time of the system.
3., this paper also introduced a simulation platform to verify the flash transfer layer algorithm. Based on FlashSim, the simulation platform was processed and added ZFTL algorithm for two times, and realized three classic FTL algorithms: page mapping, DFTL and FAST..
This paper uses simulation steps finally obtained from real-life access request as the input source in different work loads of four kinds of FTL algorithm in the paper is simulated. Through comparative analysis, the ZFTL scheme has obvious advantages, in the actual application will greatly improve the performance and reduce the cost of NAND Flash.

【学位授予单位】：中国地质大学（北京）
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

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