Return_Values

   Upon successful completion, the mrd_unload(3mrd) function returns
   the value MRD_STATUS_SUCCESS. If the mrd_unload(3mrd) fails the
   returned status value may be set to one of the following values.
   Other values that correspond to specific SCSI errors may also be
   possible, but these are the most likely.
 

Additional information available:

MRD_STATUS_PARAM                MRD_STATUS_ROBOT_COMM_ERROR
MRD_STATUS_SLOT_INVALID         MRD_STATUS_CART_INVALID
MRD_STATUS_SOURCE_EMPTY         MRD_STATUS_DESTINATION_FULL
MRD_STATUS_CART_NOT_AVAIL       MRD_STATUS_DEVICE_INVALID