Software reliability modelling and optimization for multi-release software development processes

During the lifespan of large software systems, iterative development procedure is commonly adopted with continuously incremental software versions released to the market. When to release each release plays an important role for balancing the competition in market and the risk of low-quality software. Traditionally, release-time issue is addressed with software reliability models for single version. How to model the reliability of multi-release software development process is our concern now. It is interesting to study the dynamics of software faults during this releasing procedure. Without the loss of generality, a specific iterative software development scenario is considered for our current study, where a software development team develops, tests and releases software version by version. The trend of the remaining number of faults over different versions is of great concern, and a modeling framework is proposed to study the expected number of remaining faults in each version. Cost model is then proposed, and cost oriented optimal release time analysis for n versions is studied. A numerical example is given for the illustrative purpose.