The need for measurement based reliability evaluation

Defensible quantitative assessments of the reliability and availability of computer systems including software are possible. This paper characterizes the need for quantitative empirically-based dependability assessment, describes some of the previous work in this area and identifies problems. While there is still ongoing research in measurement-based analysis of computer dependability, the techniques developed in this area have achieved significant experimental results. Measurement-based analysis can also provide verification of assumptions and parameters used in the design models. The results are useful for designing and maintaining highly-dependable computer systems intended for use in safety critical applications.