Disclosed is a combined pass through and load/unload system for automated data storage libraries. Separate portals open into each of the libraries. A pivoting robot supports a housing which is capable of supporting at least one removable multi-cartridge magazine, and pivots about a pivot axis. An actuator withdraws or extends the housing toward or away from the pivot axis. A pass through controller operates the pivoting robot to position the housing at a portal and operates the actuator to extend the housing into the portal so that the library may load and/or unload the data storage media into or out of the removable magazine(s) in the housing. The controller then operates the actuator and robot to withdraw the housing out of the portal. The controller may position the housing at the bulk load/unload position so an operator may unload and/or load magazines from the housing. The controller may position the housing at the portal of the other library to allow the transfer of media thereto. Each library may have a pass through controller and the other library may position and extend the housing into its portal, whereby the picker of the other library may unload the data storage media.