End-to-end Real-time Corba

The coexistence of heterogeneous entities in the large scale distributed systems makes it more and mo-re difficult to develop distributed applications. CORBA provides distributed objects the ability of transparent interoperability even if they are on different platforms or written in different languages, so recently it becomes an important research area in the distributed computing field. In recent years more and more real-time applications run on distributed systems, but CORBA doesn't support real-time application. The OMG issues Real-Time CORBA specification for implementing real-time application based on CORBA. In the thesis, study on the Real-Time CORBA and an implementation of Real-Time CORBA are presented.Firstly, features of real-time system and characteristics of distributed system are described. After discussing real-time problems about distributed system, we put forward the principle of implementing real-time distributed system.In the following, the architecture of CORBA is described, including object request broker, interface definition language, language mapping, stub and skeleton, dynamic invocation, interface repository and implementation repository, object adaptor and interoperability of ORB, etc. Based on the architecture of CORBA, the real-time expansion of CORBA and the OMG's Real-Time CORBA specification are discussed.After study on real-time distributed system and Real-Time CORBA specification, a model of end-to-end system is overall analyzed. In order to build a schedulability system, we discuss scheduling algorithm and synchronization protocol. At the same time, we use PERTS to assign priority to Real-Time CORBA task, and enhance schedulability of whole system.Based on the research and development given above, an available Real-Time CORBA (rtORB) is implemented. Several methods are used to optimize its performance. A series of test show that rtORB is capable enough to support real-time application.