A pragmatic approach to harnessing formal specification

In the 1980s the promise and potential of formal specification was drastically undermined, in part from those claiming that it would solve all problems in the development of software based systems. Formal, mathematically-based notations, had been used with some effect at the level of code in the form of program-proving, usually in the form of constructing statements of pre- and post-conditions and invariants, followed by proofs that sections of code were totally constrained by these aspects. Program proving was applied successfully to several notable high-profile and safety-critical projects, mostly in the defence and space areas. It was also used in hardware design. The paper considers four aspects in the adoption of formal specification.