Extensions to an approach to the modeling of software testing with some performance comparisons

It is shown how a major (and questionable) assumption underlying a previously reported approach to the modeling of software testing can be relaxed in order to provide a more realistic model. Under the assumption of uniform execution the new model is found to perform only marginally better than the previous model, indicating that the uniform execution assumption is a poor one. A nonuniform execution model is then shown to give very good performance on application to three sets of software reliability data. Attention is also devoted to the problem of comparing the performance of different models, and some difficulties in this area are noted.