An empirical study on reliability evaluation for a real time switching system

We present an empirical model to evaluate reliability of a large software system. We take as a target system a large real-time switching system which is under development in our research institute. The results obtained from our reliability model indicate that there is close relation between software failures collected during the development of the system and reliability of the system. We also analyze, through a statistical analysis of the observed failure data, the development procedure and reliabilities of respective subsystems constituting the target system in order to investigate the effects of individual reliabilities of the subsystems on the state of the whole system. The results show both relationships among subsystem groups and the dependencies between subsystems and the whole system. Our empirical reliability model can be used as a reference model to study the reliability of real-time systems similar to ours in functional structure.