Much has been done concerning the repairable system M/G/1 and plenty of results have been obtained. But those results are mainly concerned with the situation of only one kind of breakdown state. In this paper, we study the repairable queueing system M/G/1 with two kinds of breakdown states (normal and abnormal). Normal breakdown is caused by the life termination of the service station and abnormal breakdown results from the operation lapse. We propose that the life length of the service station has exponential distribution and that both normal and abnormal repair times have general distribution. By the method of Vector Markov Process, we obtain some characteristics of the system, main reliability indices of the service station, and important performance measures of the queue.
