In this paper, we propose and present Real-Time Channel-based Reflective Memory (RT-CRM)-a useful programming model and middleware communication service for constructing distributed real-time applications on platforms, open systems. RT-CRM provides remote real-time data reflection abstraction using a simple writer-push model. This writer-push approach enables us to easily decouple the QoS characteristics of the writers from that of the readers. This decoupling is crucial in supporting different kinds of remote data transfer and access needs that one often finds in distributed real-time systems. We describe the design of RT-CRM, along with a set of easy-to-use API to access the RT-CRM service. We have implemented RT-CRM as part of a larger real-time middleware project, MidART. We address many of the important implementation issues, including buffer management and QoS support. We demonstrate the feasibility of RT-CRM through a discussion of our application programming support and performance data.

We address the problem of middleware design for constructing ATM LAN based distributed industrial plant monitoring and control systems. In particular, we present a real-time client-server programming model based on a uniform ATM network. This model is being realized in our middleware called MidART. The middleware provides a set of industrial application specific but network transparent programming abstractions and application programming interface (API) that support individual application QoS requirements. In order to achieve on-demand transmission of plant data, we have developed a concept called selective real-time channels to be supported by MidART. We present the design and protocols of selective real-time channels and describe how QoS requirements of applications are guaranteed.

Data sampled from plants are registered as temporal data, combined with time stamps. We developed a real-time data server which periodically acquires temporal data and transmits them to clients for graphic presentation. The real-time data server consists of multi threads scheduled based on the rate monotonic theory. This paper explains the design of a real-time data server. The prediction for schedulability of it based on the rate monotonic theory has been verified with an experiment on an actual system.>