A real-time system description language

Building complex real-time systems requires languages and tools that permit careful specification of the system design as well as providing automatic calculation and analysis. If this design and analysis environment is well done, it should be able to accommodate modification of the system design through simple specification changes and then rerunning the analysis tools. A critical aspect of such an environment is simultaneous support for conflicting goals: design by layered abstractions which conceal implementation details, and accounting for those implementation details which are necessary to ascertain timing correctness. In this paper, we discuss the implementation of a system description language (SDL) that is part of an environment developed to address these problems. We have experimented with the SDL in several applications including a robotic pick-and-place circuit board assembly, flexible manufacturing, and a distributed real-time scheduling simulation. In each case, the SDL provided significant benefits with regard to ease of modification, timing analysis and automatic linking and loading of the target system.