ABSTRACT
Throughout the last chapter it was stressed that in order to produce a safe working environment, safety should be the concern of all; is this also the way to ensure safe system design? If so, at what level does system safety begin? Can chip design, for instance, have any influence on the ultimate safety of the product into which it is incorporated, given that the chip designer may not be aware of all the multitude of applications for which it may be destined? It seems unlikely that safety considerations can be an influence at this stage. We suppose then that the system safety begins to be an entity when the proposed system is first postulated and the safety system specified. There is now no escaping the original question; who has the responsibility for ensuring the safety and integrity of the final product? There are two extremes; either everyone is responsible for safety or responsibility is delegated to a single person. In reality, neither of these options is perfect. In the first case, human nature being what it is, no-one does anything as they assume, falsely, that everyone else is doing it for them. The second case actively encourages others to take no responsibility for, and therefore no interest in, matters of safety. A judicious blend of the two would appear to be the optimum. While overall responsibility for the quality and integrity of the safety systems ought to be invested in one person, that does not preclude other personnel being aware of the safety ramifications in so far as they affect their own field of work. Such total responsibility may well be conferred on the quality manager of a software house. Since any mishap could result in personal liability, such personnel should be strongly supported by company procedures to assist them in this task. W hatever the personal liability, the company will retain a vicar ious liability for the actions of their employees. This chapter will explore areas of legal liability and also other mechanisms for regulating these potentially hazardous activities as well as considering the factors which should be taken into account by software engineers engaged in producing software for safetyrelated applications.
