Reconciling Real-Time with Asynchronous Message Passing

At rst 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