The integration of control and dataflow structures in distributed hard real-time systems

The control structure of many real-time applications are naturally described by state machines. However the state transitions of these machines are governed not only by the state of the system and the occurrence of events, but also by their time of occurrence. The control structure of a real-time system determines what computation to perform and the set of timing constraints in effect at all times. The computation performed by the system can then be modeled by a directed graph, where the nodes denote transformations on the data and the edges denote data flow. In this paper we discuss some research issues that arise from the integration of control flow with data flow