Open Source Software Reliability Growth Model by Considering Change- Point

The modeling technique for Software Reliability is reaching its prosperity. Software reliability growth models have been used extensively for closed source software. The design and development of open source software (OSS) is different from closed source software. We observed some basic characteristics for open source software like (i) more instructions execution and code coverage taking place with respect to time, (ii) release early, release often (iii) frequent addition of patches (iv) heterogeneity in fault density and effort expenditure (v) Frequent release activities seem to have changed the bug dynamics significantly (vi) Bug reporting on bug tracking system drastically increases and decreases. Due to this reason bug reported on bug tracking system keeps an irregular state and fluctuations. Therefore, fault detection/removal process can not be smooth and may be changed at some time point called change-point. In this paper, an instructions executed dependent software reliability growth model has been developed by considering change-point in order to cater diverse and huge user profile, irregular state of bug tracking system and heterogeneity in fault distribution. We have analyzed actual software failure count data to show numerical examples of software reliability assessment for the OSS. We also compare our model with the conventional in terms of goodness-of-fit for actual data. We have shown that the proposed model can assist improvement of quality for OSS systems developed under the open source project.