Safety issues in the comparative analysis of dependable architectures

This paper illustrates the value of analytical techniques for the safety analysis of dependable architectures at the system level. Its important contributions are: (1) comparative analysis of five common hardware architectures for life-critical applications; (2) demonstration of the effect of various coverage parameters on system safety; and (3) illustration of important metrics in evaluating system safety. Discrete space, CTMC (continuous time Markov chains) are used to model the five architectures at the building block level: a simplex architecture; two gracefully degrading architectures with and without repair; and two hard-failing architectures