Software safety and reliability
Galen Williamson · IEEE Potentials · 1997
Gradually, but surely, our lives are being entrusted to computers and embedded microprocessors. As these systems become more "intelligent" and complex, the possibility for failure either at the hardware or software level increases. Technology from the large scale mainframe computers to small embedded processors that control the timing of a microwave oven or the deployment of automobile airbags affect us directly and indirectly. The testing, verification and validation of these new technologies has become an important issue. This is essential when a software or hardware related failure could result in injury or even death. What is a safety critical system? This is any system that either directly or indirectly ensures the safety of the individuals entrusted to its use or operation; or, a system that, when a failure of the system occurs, could result in personal injury or loss of life. The systems need not be complex or microprocessor controlled. The brakes in an automobile are certainly safety critical, since their failure can result in lives lost. However, we focus on microprocessor controlled systems of medium to high complexity.