The Research On The Real-Time Of Embedded Linux

With the spreading application of the embedded system, it has come into our life. Development of embedded real-time operating system has been the hotspot during the past several years. Now some embedded real-time operating systems are very costly and its development cost is very high. Their technology is secret. Linux operating system has changed the condition. Because of some characters of the Linux, it has become one of the ideal options of the embedded operating system.At first, the article introduce the conceptions, characteristics and developing history of the embedded system and embedded real-time operating system. We can get the background information of the problem. The real-time property is the obstacle of Linux in the embedded real-time application. So the real-time Linux is a focus of the embedded Linux research.At first we analyze the real-time mechanism of the Linux. Then we decided the dual kernel program of RTLinux as our research object. A simple real-time kernel is inserted between the hardware and the Linux kernel and satisfy hard real-time requirements. It has a little change to the original Linux kernel. The key technologies include interrupt emulation, fine-grain timer, real-time scheduler and so on. They are analyzed in the article. We test the RTLinux performance and get the anticipated results. We give a improved real-time scheduling program which support several scheduling policy. Several points to be approved in the dual kernel program are listed at last.Differentiating from the desktop system embedded Linux development is in a constrained environment in which computer memory and processing power are limited and require the software be efficient. The article introduce the embedded Linux development environment and the approach of the miniaturization of the kernel and the file system. We build a embedded Linux system prototype and realize a embedded IPSec VPN gateway application which can be used on the home-gateway.