基于实时系统的Flash文件系统的研究与应用

发布时间：2018-05-18 04:35

  本文选题：文件系统 + NAND　； 参考：《广东工业大学》2012年硕士论文

【摘要】：在以往嵌入式系统主要在控制领域应用,在数据存储方面的要求并不是很高。但随着信息技术的不断发展,嵌入式技术在诸多领域得到广泛应用,嵌入式系统中要存储的数据信息量不断增长,对数据存储和管理的需求越来越高,所以嵌入式文件系统的研发有着重大现实意义。 由于嵌入式设备在体积、功耗、防震等方面比较苛刻。Flash存储器具有体积小,存储容量大,能耗低,性价比高等特性,相比于传统存储介质,更适合在嵌入式系统中储存数据,已经成为是嵌入式系统中主要使用的存储介质之一。目前,已经出现很多针对闪存的嵌入式文件系统,但仍然存在许多的不足,包括启动加载时间长,内存消耗多,磨损平衡不充分等。 本文针对当前NAND Flash嵌入式文件系统的各种不足,分别提出了优化的方法。(1)启动加载时间长问题。在现有的NAND Flash文件系统YAFFS中,一个块中(block)同时存放文件属性信息和文件数据,启动时要扫描完整个Flash中的块。本文通过改变了文件存储格式和管理方式,将文件属性与文件数据存储于不同的擦除块,启动加载时只扫描存储属性的擦除块,从而减少启动加载时间。(2)内存消耗大问题。因为系统把大量控制信息均存储在内存中,使内存消耗大。本文借鉴程序局部性原理,仅在内存中保存最近访问的文件信息,减少文件系统对内存的占用。(3)磨损平衡问题。本文通过将数据分成冷热数据两类,把它们交替地储存在不同类型的空闲块上,从而达到擦除块间的磨损均衡。 依据上述方法,在研究现有YAFFS文件系统的基础上,设计了一个新的NAND Flash文件系统—-NFFS。在测试中,NFFS启动加载时间相比减少,内存消耗也减少,磨损更加均衡,达到了预期的效果。但是系统读写数据的速度因此受到影响,有所下降。最后把该文件系统应用于一个实际项目《食品安全追溯系统》中,以文件的形式保存交易的记录,基本满足项目的要求。下一步工作就是不断改进系统的设计,进一步完善系统功能,提高系统的稳定性和鲁棒性。
[Abstract]:In the past, embedded system is mainly used in control field, but the requirement of data storage is not very high. However, with the continuous development of information technology, embedded technology has been widely used in many fields. The amount of data information to be stored in embedded systems is increasing, and the demand for data storage and management is increasing. So the research and development of embedded file system has great practical significance. Because embedded devices are more demanding in volume, power consumption, earthquake resistance, etc. Flash memory has the characteristics of small volume, large storage capacity, low energy consumption and high performance-to-price ratio, so it is more suitable for storing data in embedded system than in traditional storage media. It has become one of the main storage media in embedded system. At present, there are many embedded file systems for flash memory, but there are still many shortcomings, including long startup loading time, high memory consumption, insufficient wear balance and so on. Aiming at the shortcomings of the current NAND Flash embedded file system, this paper puts forward the optimization method. In the existing NAND Flash file system (YAFFS), a block is stored in a block at the same time to store the file attribute information and file data, and scan the block in the whole Flash when starting. This paper changes the file storage format and management mode, stores file attributes and file data in different erasure blocks, scans only the erasure blocks of storage attributes when starting loading, thus reduces the problem of large memory consumption. Because the system stores a large number of control information in memory, making memory consumption. Based on the principle of program locality, this paper only saves the recently accessed file information in memory, and reduces the problem of wear and tear balance between file system and memory. In this paper, we divide the data into two classes, and store them alternately on different types of free blocks, so as to achieve the wear equalization between erasure blocks. According to the above method, a new NAND Flash file system, NFFS, is designed on the basis of studying the existing YAFFS file system. In the test, the load time of NFFS is reduced, the memory consumption is reduced, the wear is more balanced, and the expected effect is achieved. But the speed at which the system reads and writes data is affected and falls. Finally, the file system is applied to a practical project called Food Safety traceability system. The record of transaction is kept in the form of files, which basically meets the requirements of the project. The next step is to improve the system design, further improve the system function, improve the stability and robustness of the system.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP368.1;TP333

【参考文献】

相关期刊论文 前10条

1 龙瑞;;YAFFS嵌入式文件系统原理分析[J];电脑编程技巧与维护;2006年10期

2 陈智育;嵌入式系统中的Flash文件系统[J];单片机与嵌入式系统应用;2002年02期

3 吴雨俊;嵌入式系统中的线性Flash文件系统设计[J];单片机与嵌入式系统应用;2003年10期

4 胡一飞;徐中伟;谢世环;;NAND Flash上均匀损耗与掉电恢复在线测试[J];单片机与嵌入式系统应用;2007年03期

5 董明 ,刘加 ,刘润生;适宜于嵌入式多媒体应用的Flash文件系统[J];电子技术应用;2002年09期

6 刘洲洲;张捷;;基于嵌入式系统的NANDFlash坏块处理和FMM实现[J];计测技术;2006年06期

7 钟忻,慕春棣;基于闪存的文件系统的实现[J];计算机工程与应用;2003年24期

8 李强,杜威,慕春棣;基于大容量闪存的嵌入式文件系统[J];计算机工程;2005年10期

9 王同洋;董永帅;吴俊军;;基于阈值控制的损耗均衡算法设计[J];计算机工程与科学;2008年03期

10 杨春林;雷航;;基于NAND Flash的嵌入式文件系统的改进与优化[J];计算机应用;2007年12期

相关硕士学位论文 前1条

1 刘庆华;一种日志式闪存文件系统的分析与改进[D];华中科技大学;2004年

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