The tape library consists of three tape storage systems of the type Oracle STK SL8500. Each system consists of 4 levels, on each of which run two Handbots. Two of the SL8500 are connected with 4 pass-throughs, and act like a single robot.
From the perspective of the using machines the entire system is a tape library consisting of two libraries with a total of 18,000 parking spaces for tapes. The 24 handbots are transporting the tapes between the parking spaces and the 44 tape drives.
Server of the storage system provide a control computer, that knows the storage locations all tapes, with the information about the tape to use and the desired drive. The control computer then checks whether access is allowed and initiates the transport of the tape.
The Handbots be controlled independently from the tape library and put the requested tape into a drive.
The tape archive is only used by the servers of the central data storage.
Users use the system indirectly by writing data to a QFS / SAM-FS file system managed by the servers.