System and method for coordinating movement of mobile drive units

From the first move drive unit, a method of moving one or more move drive units in work space includes a stage of receiving a reservation request which requires use of the first course segment, in order to move in the first direction. This method includes a stage of judging further the current position of the second move drive unit being carried out on the first course segment, and a stage of judging whether the second move drive unit moving in the first direction. This method answers judging with the second move drive unit not moving in the first direction, and includes a stage which transmits a request-to-print-out-files response which shows that the reservation request is refused. The second move drive unit answers judging with moving in the first direction again, and this method includes a stage which transmits a request-to-print-out-files response which shows that the reservation request is recognized.