端到端系统的实时CORBA的研究

【作者】 俞岭；

【导师】 刘锦德；

【作者基本信息】 电子科技大学 ， 计算机应用技术， 2003， 硕士

【摘要】 随着分布式应用规模的日益庞大，分布式系统中不可避免地包括各种异构实体。CORBA提供了分布式环境中对象之间的透明性互操作，使应用程序可独立于软硬件平台、网络协议、编程语言，因此近年来已成为分布式对象计算领域的重要研究方面。在近几年，越来越多的实时应用运行在分布式系统中，但是CORBA并不支持实时应用。为了能够实现基于CORBA的实时应用，OMG组织发布了实时CORBA规范。本文从理论和实践两个方面对实时CORBA进行了深入研究。 论文首先研究了实时系统和分布式系统的特征；根据两者的特点，对分布式系统的实时性进行了探讨；并提出了实现实时分布式系统的原则。 论文接着研究了OMG的CORBA规范，CORBA的关键组成部分，包括：ORB核心、OMG界面定义语言、语言映射、存根和框架、动态调用、界面仓库和实现仓库、对象适配器以及ORB之间的互操作协议。在此基础上，我们探讨了对CORBA的实时扩展，并研究了OMG的实时CORBA规范。 在研究了实时分布式系统和实时CORBA规范的基础上，论文全面分析了端到端系统的模型，论述了实时CORBA端到端的调度算法及同步协议，并结合PERTS工具指出如何委派实时CORBA任务的优先级，从而提高了整个实时CORBA系统的可调度性。 在上述的研究基础上，论文最后给出了一个实时CORBA原型(rtORB)。在实现过程中，采用了多种优化手段，合理地处理了性能优化问题。对rtORB的性能测试结果表明，该实时CORBA完全可以支持实时应用。更多还原

【Abstract】 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.更多还原