Embedded And Real Time Linux System ERLinux

In these years, embedded systems are used widely, Linux is a widely used operating system in embedded systems. But embedded operating system should be small and support real time capabilities, Linux is a common operating system, it does not have these abilities. This paper is based on Linux 2.6.10, boosts up Linux's real time capabilities, build up a real time Linux system ERLinux(Embedded and Real-time Linux).First this paper introduce current status of research on real time Linux, and explain the method of develop kernel program and how to set up kernel debug environment, then analyze the new specific of Linux 2.6 real time capabilities. But there are some defects in kernel which does not support real time. Linux use static priority while scheduling real time process, when access critical section and other shared resources, there will be the problem of priority inversion. In this paper the priority inheritance protocol is used in Linux kernel to provide such problem and use priority wait queue instead of Linux's FIFO wait queue to manage blocked processes. Device management is important for the system performance and real time capabilities. But Linux's device management is focus on the system throughput and fairness, in this paper a real time I/O schedule program which use muti-priority queue is introduced, use process's priority as a main factor when scheduling I/O request. We use benchmark tools to verify the performance of ERLinux. The data shows that ERLinux improve kernel's real time performance.ERLinux is tested by LTP, it is accorded with POSIX.1 standard. We can use it in embedded real time system.