The Modelling And Application Of A New Model Of Software Reliability And Safety

With the rapid growth in software engineering from the 80th last century, software is used in more and more fields, so that we have to think more about the quality of it. Among software quality standards, software reliability is most important one, and software safety is one of the most difficult issues about software.Since software reliability and software safety are important properties of software quality, this thesis built a new model to approximately estimate the safety of software based on the software reliability models. When building the model, the concept of Nonhomogeneous Poisson Process (NHPP) will be introduced, as well as the properties of it, the parameter estimate method and the existing software reliability models.According to the wrong use of the term "software safety" in China, this thesis also presents the definitions of the related concepts and shows the difference of them.Then a new software safety model is build based on a real software environment and some software engineering thoughts.Finally, a group of real software test numbers are used in both the new model and the generate one; the comparison and the conclusion are drawn. That is: to estimate software safety, the models only based on software failure data are not fit the real operating environment. To better estimate software safety, the software safety test but not only the software reliability test is badly needed.