The design and implementation of real-time CORBA 2.0: Dynamic scheduling in TAO

In an emerging class of open distributed real-time and embedded (DRE) systems with stringent but dynamic QoS requirements, there is a need to propagate QoS parameters and enforce task QoS requirements across multiple endsystems in a way that is simultaneously efficient and adaptable. The Object Management Group's (OMG) Real-Time CORBA 2.0 specification (RTC2) defines a dynamic scheduling framework for propagating and enforcing QoS parameters dynamically in standard CORBA middleware. This paper makes two contributions to research on middleware for open DRE systems. First, it describes the design and capabilities of the RTC2 dynamic scheduling framework provided by TAO, which is our open-source CORBA standards-based Object Request Broker (ORB). Second, it describes and summarize the results of empirical studies we have conducted to validate our RTC2 framework in the context of open DRE systems. The results of those experiments show that a range of policies for adaptive scheduling and management of distributable threads can be enforced efficiently in standard middleware for open DRE systems.