Formalisms and structures
Michael Jackson · Formal Methods · 2012
Two fundamental pillars of Software Engineering practice are formalism and structure. Formalism allows engineers to reason rigorously about the system in hand; structure allows them to understand its purposes and behaviours. In the constructive activity of system development structure must therefore take precedence. The central role of formalism is to check and verify -- or, where necessary, correct --the products of more informal modes of thought.In this talk these ideas are explored in the context of an illustrative system. The large structure of the system functionality is discussed, together with the nature of the components of that structure. Informal criteria of functional simplicity are presented. The inescapable mismatch between an intelligible functional structure and implementable software architecture is exposed. The role of formalism in these concerns is suggested.