Analysing high-integrity systems

Computers are being used increasingly in systems where the cost of error or failure might be extremely high. Some systems depend upon computers to maintain safety or contribute to the maintenance of safety. In other systems, incorrect operation may pose a threat to security, e.g. compromising the confidentiality and integrity of certain military information. Costs of failure may simply be financial, e.g. the unavailability of automated share dealing systems or banking systems. It is becoming increasingly common to talk about enterprise critical systems whose failure could result in severe harm, e.g. bankruptcy, to an enterprise or organisation. The criticality of such systems means that all practical measures should be taken to ensure that the associated risks are tolerable. This implies (inter alia) that such systems (including the software components thereof) must be subject to extensive analysis and testing before they are deployed. In many cases there is a formal clearance or certification process prior to deployment.<>