The authors consider two main types of component-based systems. One type has, architecturally, little interaction between components. Thus, its reliability is some sort of mathematical expression of the total reliability. The other type is the case where components change in importance, such as when they are called more often.

There are reliability equations for the single input, single output case; the single input, multiple output case; and the multiple input, multiple output case, all proven in a previous paper [1]. Here, they are solved for a reliability estimate using Markov models. This paper is a candidate to be in every tester’s library.