SPIL: a new graphical design notation

A description is given of SPIL (system, process, I/O, logic), a graphical software design notation developed by the authors for use on avionics projects and intended to be used to describe software design. Some of the elements which it incorporates in user-friendly diagrams are: design from the viewpoint of the process; logic and control at the module/process level; data structures and data flow; and hierarchical diagram structures with decomposition analogous to that provided by the Structured Analysis and Design Technique (SADT).<
>