The SCSI-2 specification for medium-changer devices allows an
    element to remember the source element of the current piece
    of media. For example, if a mrd_load(3mrd) is performed from
    slot 17 to drive 2, the element information for drive 2 will
    remember that the media came from slot 17. Where this feature
    is implemented, it allows an application to query an element to
    learn the original source of the media in it and return it.

    The mrd_home(3mrd) function does this. Given a robot name and
    element address it will see if the source address is valid
    and when it is return that media to its original location.
    If the source address is invalid or the element unavailable
    an error will be returned. The routine will also check to see
    if the media was inverted when placed in the current element
    and restore it to its original orientation. When the move is
    complete, the resulting address and element type will be copied
    into destination_name and destination_type.

    If the volume_tag argument is used, the routine will verify that
    a cartridge with the volume tag is present in the element before
    performing the move.