A real-time validator

The verification and validation of representations of the evolving software artifact plays a key role in many approaches to software development. The representations range from specification and design documents to the program code itself. The authors present a real-time validator (RTV) that was developed for an application in telecommunication switching. They overview the specification model used and introduce the key structure of the validator-the model of beliefs about permissible behavior of the system. They show how this model is related to the specification model and present a rule-based representation of belief models. The authors describe an implementation of the validator and discuss their experience with its use in detection of failures for a small telephone exchange