Sensitivity of Two Coverage-Based Software Reliability Models to Variations in the Operational Profile

Software in field use may be utilized by users with diverse profiles. The way software is used affects the reliability perceived by its users, that is, software reliability may not be the same for different operational profiles. Two software reliability growth models based on structural testing coverage were evaluated with respect to their sensitivity to variations in operational profile. An experiment was performed on a real program (SPACE) with real defects, submitted to three distinct operational profiles. Distinction among the operational profiles was assessed by applying the Kolmogorov-Smirnov test. Testing coverage was measured according to the following criteria: all-nodes, all-arcs, all-uses, and all-potential-uses. Reliability measured for each operational profile was compared to the reliabilities estimated by the two models, estimated reliabilities were obtained using the coverage for the four criteria. Results from the experiment show that the predictive ability of the two models is not affected by variations in the operational profile of the program.