Formal Methods and Software Safety

The safety of software is becoming increasingly important as computers pervade control systems on which human life depends. Whilst hardware has become significantly more reliable over the years, the same cannot be said of software. This has become more complex and methods to ensure its correctness have been slow in development. One approach is to mathematically verify software in such systems. This paper investigates the industrial use of these techniques, their advantages and disadvantages, and the introduction of standards and their recommendations concerning formal methods in this area. The cost of safety is also considered. Keywords: Safety; reliability; system integrity; standards; education; digital systems; computer software; formal languages; industrial control; software engineering