Design And Implementation Of An Embedded Time Predictable OS

Embedded systems have different needs at different scenarios,under hard real-time applications,the demand for embedded systems are not only higher performance,more importantly,high security and high reliability.System as aerospace control systems,and nuclear power plant control system,is very demanding of time.Therefore,the time as the core of the design basis is gradually being taken seriously.Either at the programming model layer and the architecture layer,high precision time and high repeatability of design are drawing more and more attentions,and becoming one of the research hotspots of the contemporary embedded era.This dissertation is committed under the exact time operating system platforms research.The main work includes:(1)providing a definition of methods and procedures in the operating system environment,and the time can be predictive assessed.In this paper,we proposed measurement procedure in the operating system under time predictability definitions and measurement methods.With combined analysis we turned out the program time predictability's granularity.(2)analyzing the execution flow and the traditional operating system's time predictability and the advantages and disadvantages arising from the mechanism to promote the message of SEFM.We argued the effect of the implementation of the programming model of the system,proposed service-oriented programming model.(3)focusing on the design of PRET-Minicore operating system based on the latest PRET called FlexPRET.FlexPRET is designed with multithread,hardware scheduling,time and other characteristics to determine the execution is designed to perform multi-stream programming model.Flexible scheduling policy and more efficient communication mechanism makes Minicore can run on PRET while maintaining the messaging service push mechanism in the core body of the execution flow.(4)proposing the system design process framework based on this platform,and discussing the design tools and Ptolemy code generation approach.For a instance with the famous TBD(Tunnel Ball Device).Device).we implemented the experiments with the framework.As we can see from the results.the execution time of service execution in strict accordance with the precise time setting can meet the design requirements.