Embedded Real-time Linux System

The real-time operation system is in dispensable in the computer field with the development of the micro-processor, but the expense of the foreign commercial products, for example, QNX, VXWORK, has increased our economic burden. UOCOS-II and Linux is free, but ucos-II is too weak, while the Linux is not real-time. We take the advantage of Linux and add a real-time module to it, which provides the real-time feature. So, the Linux with the real-time RTAI can meet the need of the embedded field.In this paper the author introduced a new micro kernel RTAL a micro operation system which is based on Linux and provides users with the real time capabilities seamlessly through sharing the hardware. RTAI mainly trapped the peripherals interrupts and if necessary re-routes them to Linux or real time tasks. It was not an intrusive modification of the Linux kernel; it used the concept of HAL (hardware abstraction layer) to get information from Linux and to trap some fundamental functions. This HA (?)provides few dependencies to Linux Kernel. RTAI provides us with the abilities to use Linux kernel to handle the common tasks and the hard real time tasks. The author introduced the system structure of RTAI, the integration of Linux and RTAI, and introduced the transplant of pipe and the shared memory during the transplant to the platform without MMU. The author had some experiments to test the RTAI system performance and had some experiments to test the context switch time in Linux and windows to compare with RTAI.After the analysis and comparison of approaches to real time Linux, this dissertation describes a realistic real-time operating system DKOS based on dual-kernel architecture, and makes thorough analysis and innovations about many problems in real-time operating systems.