On the Development of Reactive Systems

Abstract

Some observations are made concerning the process of developing complexsystems. A broad class of systems, termed reactive, is singled outas being particularly problematic when it comes to finding satisfactorymethods for behavioral description. In this paper we recommend therecently proposed statechart method for this purpose. Moreover, itis observed that most reactive systems cannot be developed in a linearstepwise fashion, but, rather, give rise to a two-dimensional developmentprocess, featuring behavioral aspects in the one dimension and implementationalones in the other. Concurrency may occur in both dimensions, as orthogonalityof states in the one and as parallelism of subsystems in the other.A preliminary approach to working one’s way through this "magic square"of system development is then presented. The ideas described hereinseem to be relevant to a wide variety of application areas.