Design and Implementation of Filesystem With Automatic Data Compression and Decompression

Along with the fast development of embedded computing and control technology, the requirement of more advanced embedded operating system and filesystem is coming up. In an embedded environment, a filesystem with automatic data compression (FWADC) can make use of resources much more efficiently than a usual filesystem, so this kind of filesystem is more suitable for the technology development situation. A new structure of FWADC is initially provided in this dissertation. This kind of structure support the share of automatic data compression feature between filesystems within one operating system. It is implemented in this dissertation and the goal is achieved well. The structure of existing FWADC does not support share of automatic data compression feature between filesystems within one operating system, i.e., we have to make a totally new implementation for every filesystem respectively. In this dissertation, a new structure of FWADC with own intellectual property right is proposed. It not only solves the problem mentioned above, but also optimizes data compression operation and reduces its negative influence to the whole operating system. Firstly, in this dissertation, the technologies and thoughts applied in this system are introduced. Secondly, the whole design is described in detail. Thirdly, the implementation of this system is discussed and related flow charts and data structures are shown at length. Fourthly, some key technologies used in the implementation are demonstrated separately. In the end, the usage of this system is shown, the features of it are summarized and the improvements which can be done in the future are also described. The design and implementation of FWADC is the core content of this dissertation. The whole process of the development of FWADC is discussed from a developer view. Not only every level contained by FWADC is described, but also the implementation is given in detail. Not only structure and flow chart of every module are shown, but also some related academic problems are discussed.

Alternate abstract:

随着嵌入式计算和控制技术的迅速发展，对嵌入式操作系统及嵌入式文件系统提出了更高的要求。具有数据自动压缩解压缩功能的文件系统比普通的文件系统更加能够有效的利用嵌入式系统的有限的资源，因而更加适应嵌入式技术发展的需要。本文创造性地提出了一种可以使得透明的数据压缩解压缩特性在同一个操作系统所支持的各种文件系统之间共享的数据压缩解压缩文件系统体系结构，并得到实现，效果显著。 现有的各种数据自动压缩解压缩文件系统的设计结构无法方便的将透明的数据压缩解压缩特性在同一个操作系统所支持的各种文件系统之间共享，每一个压缩文件系统都要独立进行设计。本文提出了一种具有自主知识产权的构架具有数据自动压缩解压缩功能的文件系统的方法。它不仅克服了现有的具有类似功能的文件系统的上述弊端，而且对压缩数据的存储进行了优化，降低了压缩解压缩操作对系统整体的影响。 首先，本文从需求分析出发，介绍了该系统采用的技术和设计思路。随后，详细的描述了系统的设计方案。接着，就系统的实现进行了详细的讨论，并给出了相应函数实现的流程图和数据结构的定义。然后对在实现中使用的一些关键技术进行了详细的说明。最后，详细讲述了系统的使用方法以及测试结果，并在此基础上对系统的特点进行了总结，同时，对今后的工作也进行了展望。 具有数据自动压缩解压缩功能的文件系统的设计和实现是本论文的核心内容。本文主要从具体设计与实现的角度讨论了这种文件系统开发的全过程。不仅深入剖析了整体实现方案，还给出了其中各层的具体实现方法，以及各代码模块的结构与流程图等,并对有关的理论问题作了一些探讨。