A graphical language for specifying and analyzing real-time systems

We present Graphical Communicating Shared Resources (GCSR), a formal language for the specification and analysis of real-time systems, including their functional, temporal and resource requirements. GCSR supports the explicit representation of system resources and priorities to arbitrate resource contentions. These features allow a designer to examine resource inherent constraints and to experiment with various resource allocations and scheduling disciplines in order to produce a more dependable specification. In addition, GCSR differs from other graphical languages through its well-defined notions of modularity and hierarchy: dependencies between system components, expressed as communication events, can have a limited scope of visibility, and control flow between components is clearly represented as either an interrupt or exception, i.e., voluntary release of control. Furthermore, GCSR has a precise operational semantics and notions of equivalence that allow the execution and formal analysis of a specification. We present the GCSR language, its toolset, and how properties, e.g., safety can be analyzed within GCSR.