Real-Time and Safety-Critical Systems

Abstract

A system is one in which the timing of the output is significant [195]. Such a system accepts inputs from the `real world' and must respond with outputs in a timely manner (typically within milliseconds — a response time of the same order of magnitude as the time of computation — otherwise, for example, a payroll system could be considered `real-time' since employees expect to be paid at the end of each month). Many real-time systems are embedded systems, where the fact that a computer is involved may not be immediately obvious (e.g., a washing machine). Real-time software often needs to be of high integrity [10].