Command_Parameters

   When MRU executes commands, it examines the commands for the 
   presence of parameters.  If you do not specify parameters to the
   keywords slot, drive, or port, MRU supplies defaults, usually 
   assuming a value of 0.

   slot_number:    An integer value indicating a physical slot in 
                   the media robot.

   drv_number:     An integer value indicating a physical drive in 
                   the media robot.

   port_number:    An integer value indicating a physical port in
                   the media robot.

   robot_name:     The name for the media robot.

   cartridge_name: The name of the cartridge as identified by its
                   external label.

   In the MRU system, drive, slot, and port numbering begins with 0.
   The default value for DRIVE, PORT, and SLOT is 0.