Design And Implementation Of Hopen Dual-kernel Operating System

Hopen, a domestic embedded real-time operating system, has not met users'requirements because of few application supports for it. This dissertation proposed adual-kernel architecture of Hopen-RT and Linux, which not only retains the real-timeperformance of the former but also supports the rich applications of the latter. Thisapproach integrits the two different OS together to work cooperatively and compatiblywithout modifying the most part of primary OS.The Hopen dual-kernel operating system proposed in this dissertation is made ofHopen-RT kernel and Linux kernel. The former takes the real-time tasks and the latterexecutes others. So it not only has real-time performance but also is compatible withall current Linux applications totally. In contrast with the traditional approach thatexecutes the real-time application as a module being inserted into the kernel, thisdissertation proposed a model of running real-time process in user space in whichreal-time task is picked up from kernel and runs in Hopen-RT user space. As a result,there will be no bad affection on kernel or any other tasks if an application crashesand the system is more stable and more convenient for application developement.The main contribution of this dissertation is as follows:(1) Propose new real-time process model and rebuild Linux process modelThe user space of Linux process was reduced from 3G to 2G, and the 1G kernelspace expanded was reserved for real-time processes. With the segmentationmechanism of i386 CPU, it provides a 32M private user space for each real-timeprocess and maps it to the identical linear address space with Linux, which ensures thereal-time performance of Hopen-RT significantly.(2) Design and implement special Hopen-RT memory management mechanismA kernel memory pages pool was designed to improve the performance of kernelmemory page operations of Hopen-RT and an efficient algorithm was adopted toallocate and reclaim kernel memory. This ensures the real-time performance ofHopen-RT. A set of interfaces of virtual memory operations was also built forreal-time processes.(3) Design and implement real-time process load schemeA file server in Linux was built to provide file operations for Hopen-RT. Theload requirements and execution results were transfered through virtual pipe andreal-time application was loaded dynamicly by sharing memory.Based on the virtual interruption system, Hopen dual-kernel operating systemwas designed and implemented in the environment of i386 architecture. According tothe experimental results, Hopen dual-kernel operating system runs stably, hasexcellent real-time performance and supports all kinds of Linux applications.