A discrete SRGM for multi-release software system with imperfect debugging and related optimal release policy

To reflect the opportunities that new technologies open up, software developing firms offer upgrades or improved versions through a series of releases by introducing some innovative or new functionality in the software distinguishing itself from the previous versions. Although each new version passes through a rigorous testing process, faults can and do sometimes get through. In this paper we propose a discrete software reliability growth model (SRGM) for fault removal process to capture the effect of faults generated in the software and incorporates the effect of up-gradations on the subsequent releases of the software. In addition, we have also discussed the related optimal release policy that minimizes the total cost and we analyze the sensitivity of parameters of proposed SRGM. The proposed model is tested on real life data set for software with four releases and the goodness of fit is also analyzed.