Computer-aided disaster

This paper describes a number of recent disasters in which computers have been wholly or partly to blame, including the Therac-25, which administered overdoses of radiation to its patients, the London Ambulance fiasco, the crashes of the Gripen fly-by-wire fighter, the failure of the Patriot missile system to defend against Scuds, problems affecting space probes and satellites and the crash of the A320 at Habsheim. It discusses what these disasters have in common, what lessons can be learned from them, how such disasters can be prevented and whether computer-based systems are inherently unsafe. The accident sequences are analysed, taking into account the underlying social and human causes, and the part played by the inherent weaknesses of computer systems, in particular their role in making systems more interactively complex and more tightly coupled