The mrd_show(3mrd) function can be used to obtain information
    about specific element types of a supported Medium-Changer.
    Medium-Changer element types that mrd_show(3mrd) can retrieve
    information about include PORT, DRIVE, SLOT and TRANSPORT. If
    a element_type of ROBOT is specified, the mrd_show(3mrd) is
    equivalent to calling mrd_startup(3mrd) - that is, robot_info
    is filled in.

    The robot_info_t data structure is described in mrd_
    startup(3mrd).

    The element_name parameter specifies the first element of the
    type element_type about which to obtain information. The element_
    count parameter specifies the number of elements of type element_
    type about which information is to be obtained.