Fostering functional safety of real-time systems with concepts of object orientation

Hard-wired control systems are increasingly replaced by program-controlled embedded systems. The programming languages currently employed for their implementation lack constructs and design patterns enforcing intelligible code fostering its verification by certification authorities. Recommendations for such constructs necessary to guarantee safety integrity are given in the international standard IEC 61508-3. One of the recommendations refers to object-oriented programming (OOP). Therefore, we analyse both basic and advanced properties of OOP like encapsulation, polymorphism, inheritance, prototyping, delegation etc. with respect to functional safety. In a resulting programming language based on PEARL90 [1] we demonstrate coding with examples from hard real-time systems.