Defect-based reliability analysis for mission-critical software

Most software reliability methods have been developed to predict the reliability of a program using only data gathered during the testing and validation of a specific program. Hence, the confidence that can be attained in the reliability estimate is limited since practical resource constraints can result in a statistically small sample set. One exception is the Orthogonal Defect Classification (ODC) method, which uses data gathered from several projects to track the reliability of a new program. Combining ODC with root-cause analysis carl be useful in many applications where it is important to blow the reliability of a program for a specific type of a fault. By focusing on specific classes of defects, it becomes possible to (a) construct a detailed model of the defect and (b) use data from a large number of programs. In this paper, we develop one such approach a,td demonstrate its application to modeling Y2K defects.