Software safety analysis of 2-out-of-3 redundant architecture system based on Markov model

With the increasing complexity of software, the software reliability and safety have already become a more important issue, especially for the safety-critical systems. So the software safety modeling and calculation method play an important role in ensuring the software reliability and safety. In this context, the quantitative analysis and assessment becomes very important, but the traditional approach often suffers from immature of safety modeling and index calculation method. This paper proposes a method on the software safety modeling, as well as the calculation method to analyze software safety at system level, module level and function unit level. As a case study, the paper studies more detail on the software safety analysis and the calculation to the quantitative indicators for the typical 2 out of 3 system by using the Markov model.