Communicating real-time state machines

Communicating real-time state machines (CRSMs), a complete and executable notation for specifying concurrent real-time systems including the monitored and controlled physical environment, are introduced. They are essentially state machines that communicate synchronously in a manner much like the input-output in Hoare's CSP. In addition, CRSMs have a novel and small set of facilities for describing timing properties and accessing real time. The author defines the CRSM language, gives many examples of its use in requirements specification, outlines an algorithm for executing or simulating CRSMs, introduces some techniques for reasoning about the specifications, and discusses some open problems and issues