Patent ID: 7546180

Claim:
A media library, comprising: a plurality of computer-readable media units; a device configured to read or write the media units; a plurality of robots constrained to move along a common axis of motion, wherein each robot has sensors disposed on opposite sides of the robot to indicate when the robot is touching another robot; and a controller connected to communicate with and control the plurality of robots; wherein the controller identifies relative positions of the plurality of robots on the common axis of motion by a series of commands and responses, wherein the series of commands and responses comprises: first instructions for directing the plurality of robots to move in a first direction as far as possible; second instructions for sequentially querying the plurality of robots regarding the presence of another robot on a first side that is opposite the first direction until a first one of the plurality of robots does not detect the presence of another robot on the first side; third instructions for providing an order designation for the first one of the plurality of robots and moving the first one of the plurality of robots away from ones of the plurality of robots that have not received an order designation; fourth instructions for performing the sequentially querying step and the providing step repeatedly until only a single one of the robots does not have an order designation; and fifth instructions for designating an order for the single one of the robots.