【作者】 郑文兵；

【导师】 李成忠；

【作者基本信息】 西南交通大学 ， 计算机应用技术， 2004， 硕士

【摘要】 随着信息技术与网络技术的高速发展，嵌入式系统越来越受到人们的重视，它被广泛地应用于科学研究、工程设计、军事技术、消费电子等方方面面。同时，嵌入式系统正变得越来越复杂，在嵌入式系统中添加嵌入式操作系统以显得越来越重要。 由于Linux的迅速发展和Linux的开放源代码、具有精巧高效的内核、可裁减性好、易于开发和使用以及适应多种CPU和多种硬件平台等优点，基于Linux的嵌入式实时操作系统的应用研究得到广泛关注。但是，由于Linux在中断机制、定时器和进程调度等方面的特点，使其在实时性方面存在很多问题，对Linux进行实时性改造是嵌入式Linux设计中的一个相当重要的问题。 本文首先介绍了嵌入式系统和嵌入式操作系统的一些概念，以及嵌入式Linux设计中需要解决的一些问题。然后，针对Linux在实时性方面存在的问题，采用标准Linux内核和实时内核两者相结合的方案设计了一个实时嵌入式Linux，其中Linux内核作为一个优先级最低的任务运行在实时内核上，负责普通Linux非实时任务：而实时内核则处理实时事件的响应。接着，论文详细介绍了嵌入式Linux在软盘上模拟实现的具体步骤，包括Linux内核的裁剪与编译、最小文件系统的构造和嵌入式Linux系统软盘的创建；同时对所实现的嵌入式Linux的实时性能进行了测试。最后，论文介绍了基于嵌入式Linux在网络方面的应用：路由器和防火墙，实现了路由功能、IP伪装功能和对网络的访问控制功能，并对所实现的功能进行了测试。更多还原

【Abstract】 With the rapid development of information technology and computer network, embedded system is more and more important. At present, embedded system has been widely used in science research, engineering, military and consumer electronic, etc. At the same time, embedded system is increasingly complicated, and it is desirable to insert embedded operation system into embedded system. Linux is a popular open-source operating system. It has an efficient, tiny and modifiable kernel. It is easy to develop and sustains most of the embedded CPU and hardware platform. Linux has been modified to become an embedded operating system, and is widely used and researched. However, Linux has many problems in real-time performance, caused by some properties of Linux, such as interrupt, timer and process scheduler. Therefore, it is one of the most important tasks to improve the real-time capability of embedded Linux. This paper first introduces some basic ideas of embedded system and embedded RTOS. Then illustrate in detail the design of real-time embedded Linux, which is composed of real-time kernel module and standard Linux kernel. Standard Linux kernel has lowest priority, it take control of none real-time task of Linux, while the real-time kernel processes real-time tasks. Next, the paper introduces the steps to set up such an embedded Linux in floppies and how to test real-time performance. Finally, introduces some applications of real-time embedded Linux in network, including Router and Firewall.更多还原