Cost Optimality in Testing and Rejuvenation

In this paper, we extend models for the test phase and the operational phase with cost aspects, to explore cost optimality in testing and rejuvenating software systems that can age. For example, we find that under limited resources it may be advisable not to focus on the removal of aging-related bugs in the test phase, rather, the adverse affects of such bugs should primarily be prevented via software rejuvenation during operations. Our model-based analysis thus helps give a further theoretical foundation for the importance of software rejuvenation.