An integrated approach to achieving high software reliability

In this paper we address the development, testing, and evaluation schemes for software reliability, and the integration of these schemes into a unified and consistent paradigm. Specifically, techniques and tools for the three software reliability engineering phases are described. The three phases are (1) modeling and analysis, (2) design and implementation, and (3) testing and measurement. In the modeling and analysis phase we describe Markov modeling and fault-tree analysis techniques. We present system-level reliability models based on these techniques, and provide modeling examples for reliability analysis and study. We describe how reliability block diagrams can be constructed for a real-world system for reliability prediction, and how critical components can be identified. We also apply fault tree models to fault tolerant system architectures, and formulate the resulting reliability quantity. Finally, we describe two software tools, SHARPE and UltraSAN, which are available for reliability modeling and analysis purpose.