With computer systems becoming ever larger and more complex, the cost and effort associated with their construction is increasing and the systems are now sufficiently complex that developers need help to analyse and understand them. However, at design time, when this understanding is crucial, the system is unavailable because it has yet to be built. Formal, executable models can help with this problem by providing developers with a platform on which to establish the feasibility of a proposed design. However, commercial developers seem reluctant to employ this type of modelling in their design activity.

This paper describes a modelling tool in which the traditional model generation technique of writing "programming language like" code is replaced with a model generation tool which uses a graphical representation of models whilst retaining sufficient formality to permit the models to be executed, or converted into code for analysis by a traditional model checking tool.