Formal Specification and Verification of Complex Systems

Abstract

The application of formal methods in the rigorous definition and analysis of the functionality and the behaviour of a system, promises the ability of showing that the system is correct. Given such a promise, that is already out since several years, it is astonishing to see how little formal methods are actually used in the safety critical system industry, though the use of formal methods is increasingly required by the international standards and guidelines for the development of complex systems. Industrial acceptance of formal methods is strictly related to the investment needed to introduce them, to the maturity of tool support available, and to the easiness of use of formal methods and tools. Nowadays, the industrial trend is directed to the adoption of formal verification techniques to validate the design, integrating them within the existing development process. Industries are more keen to accept formal verification techniques assessing the quality attributes of their products, obtained by a traditional life cycle, rather than a fully formal life cycle development, due to the lower training and innovation costs of the former. Several approaches to the application of formal methods in the development process have been proposed, differing for the degree of involvement of the method within it. Starting from rigorous specifications, formal methods can be used for the derivation of test cases, or as a validation technique aimed at proving that the specification satisfies the requirements, or as an auxiliary technique in the automated generation of code. The Formal Methods &&Tools Group of ISTI-CNR is active in the fields of development and application of formal notations, methods and software support tools for the specification, design and verification of complex computer systems. These systems often share important features like concur-