1. An apparatus for switching library managers, the apparatus comprising: a communications module configured to receive a directive to transition library management functions from a first library manager to a second library manager, the communications module further configured to communicate with the first library manager, the second library manager, and a host computer; and a control module configured to direct the first library manager to reject data transaction commands, except for new data transaction commands of a specified data transaction command type, while maintaining a storage device in a state responsive to data transaction commands of the specified data transaction command type during the transition of library management functions from the first library manager to the second library manager; also suspend the library management function of the first library manager; and activate the library management function of the second library manager.