Embedded Linux And Real-time Issues

Researching the mechanism of general OS, modifying and extending its some ingredients to provide some properties such as micromation component and real-time is a current tendency. Based on a specific application of intelligible paver control system, the thesis selects Linux as the research object, and from which expects to derive an embedded Linux which can meet the demands of the application, and provides some characteristics as micromation component and real-time.The thesis firstly analyses the source code of the main function modules of Linux, then makes researches into its architecture, and the working mechanism and data structure of the three main modules. As for the two aspects of micromation and component, with referring the latest development of OS theory, the thesis introduces how to modify the Linux function ingredient by using micro-kernel structure.Subsequently the thesis mainly focuses on real-time problem of embedded Linux. Firstly the thesis analyses the interrupt mechanism and scheduling policy of general Linux, then points out the primitive reasons resulting in non real-time of general Linux, finally presents a newmodifying method--using real-time theory and open-system structuretechnology to enhance real-time property of the embedded Linux. To bring such method into practice ,the thesis establishes the task model of paver control system, then based on this model gives the design of two level scheduling mechanism which is comprised of two scheduling parts-RM algorithm and Deferrable Server algorithm. In the end, the thesisalso gives qualitative and quantitative analysis about the scheduling feasibility and performance of this two level scheduling mechanism through applying to the paver's real-time task set.In the last part, by using a specific open system structure technology--Hierarchical loadable scheduler framework, the thesis reduces thetwo level scheduling mechanism to actual programs.