At first sight, real-time and asynchronous message passing like in SDL and ROOM seem to be incompatible. Indeed these languages fail to model real-time constraints accurately. In this paper, we show how to reconcile real-time with asynchronous message passing, by using an assumption which is supported by every mailing system throughout the world, namely that messages are time-stamped with their sending and arrival time. This assumption allows us to develop a formalism which is adequate to model and to specify real-time constraints. The proposed formalism is shown at work on a small real-time example.
In Proc. of the FME'97, the 4th International Symposium Formal Methods Europe, Graz 1997.