Software Reliability Prediction for Large Systems

Quality improvement such as increased reliability and maintainability are of utmost importance in software development. In this field, which was previously ad hoc and unpredictable rather than customer oriented, increasing competition and decreasing customer satisfaction have motivated management to put more emphasis on quality issues. Failures in telecommunication systems recently showed that low software quality in such a sensible field has much more effect than defects located to a distinct application. This paper provides insight in techniques for reliability prediction as they are applied within the development of Alcatel 1000 S12 switching software. Release time prediction and field performance prediction are both based on tailored ENHPP reliability models. For the complete approach of criticality prediction recent data from the development of a switching system with around 2 MLOC is provided. The switching system is currently in operational use thus allowing for validation and tuning of the prediction models.