QoS Model And Strategies For Embedded Real-Time Middleware

Real-time systems differ from non-real-time systems in many significant aspects such as timeliness, predictability, reliability, durability, etc. With the development of distributed real-time system, new problems such as real-time communication, heterogeneity are introduced in real-time systems. Real-time systems nowadays tend to be more and more complex and large in scale, and need to be more flexible, autonomous, reliable and adaptive. This brings forward high requirement for the design and development of real-time systems. Traditional design and developing methods of real-time system are close and appropriative, and seldom take into account the adaptability to environment. Thus they can't satisfy the requirements of modern complex distributed real-time applications.Non-functional requirements to real-time systems such as timeliness, reliability, security and throughput can be considered as to QoS(Quality of Service) requirements of application layer which are put forward by real-time application, and the service provider is a development and execution platform for real-time applications. What is the relationship between QoS requirements of application layer and network layer, operating system layer, and middleware layer? Can the design and development of real-time system be simplified by using low-layer QoS mechanisms? These are the focuses of this dissertation.ARTs-OS is an embedded real-time operating system developed by Huaxiang Software Research and Development Center. ARTs-ORB is an embedded real-time middleware based on the system. It is used to support the execution of request which has QoS requirements in embedded real-time environments.There are many critical technologies in designing and realizing the QoS management component, including QoS management model and all kinds of strategies and mechanisms ensuring QoS and so on. In the QoS management model, designing problems and requrements are analyzed and a layered adaptive management model that have the ability to adjust QoS actively is proposed, it also describe the implementation of QoS manager and QoS monitor in kernel module of QoS management;In the strategies and mechanisms, all kinds of strategies and mechanisms that ensure the service quality in message transfer,multi-thread concurrency and resource management are implemented.