Lessons from Formally Verified Deployed Software Systems

Abstract

e technology of formal so ware veri cation has made spectacular advances, but how much does it actually bene t the development of practical so ware? Considerable disagreement remains about the practicality of building systems with mechanically-checked proofs of correctness. Is this prospect con ned to a few expensive, life-critical projects, or can the idea be applied to a wide segment of the so ware industry? To help answer this question, the present survey examines a range of projects, in various application areas, that have produced formally veri ed systems and deployed them for actual use. It considers the technologies used, the form of veri cation applied, the results obtained, and the lessons that can be drawn for the so ware industry at large and its ability to bene t from formal veri cation techniques and tools.