Long-run availability of paralleled systems

Summary This paper gives an analysis of a system withN ₁ components of one type andN ₂ components of another type in parallel with uninterrupted running times of each component following exponential distribution and the repair time following arbitrary distribution. The head of the line and preemptive resume priority disciplines have been imposed on the repair of the components. The busy period process is investigated first using the supplementary variable method. Then the general time dependent process in which busy periods alternate with idle periods has been studied in terms of the busy period probabilities and probability of finding the repair facility idle at timet. Finally, the long-run availability of the system in terms of the steady state probabilities for the two cases of priority disciplines has been obtained.