Manufacturing flow systems consisting of machines separated by buffers of finite capacity have been studied a lot in the literature because systems of this type are widely encountered in industry. The basic assumptions are that the processing time of each machine is deterministic and machines are subject to random failures. Failure and repair times of each machine are characterized by probabilistic distributions. The corresponding model is referred to as the asynchronous model. The basic configuration that has been widely studied is the so-called production lines. Analytical methods for performance evaluation of production lines have been developed for two different models: the synchronous model and the continuous flow model. For the range ...