  Many product lines are critical, and therefore reliability is a vital part of
their requirements. Reliability is a probabilistic property. We therefore
propose a model for feature-aware discrete-time Markov chains as a basis for
verifying probabilistic properties of product lines, including reliability. We
compare three verification techniques: The enumerative technique uses PRISM, a
state-of-the-art symbolic probabilistic model checker, on each product. The
parametric technique exploits our recent advances in parametric model checking.
Finally, we propose a new bounded technique that performs a single bounded
verification for the whole product line, and thus takes advantage of the common
behaviours of the product line. Experimental results confirm the advantages of
the last two techniques.
