HCDM: A HIERARCHICAL DESIGN METHOD FOR CHILL BASED SYSTEMS

Abstract This paper presents a graphical design method for the hierarchical, stepwise decomposition of large, distributed CHILL based real time systems (major application areas will be public and private switching and railway signalling systems). With the socalled ' hierarchical CHILL Design Method ' (HCDM) a system is described by a physical model defining the hardware topology, the functionality is defined using SDL concepts by stepwise hierarchical decomposition into function blocks (static model). The dynamic behavior of these blocks is modelled with ' finite Message Machines ' (finite state machines with message communication) which are represented by SDL type diagrams. Computer support for HCDM (including graphics editor, design database, consistency checker, CHILL-skeleton generator etc.) is provided by the ' Graphical Software Design System ' (GSDS).