o  robot_info - This is the address of a robot_info_t structure
       initialized using mrd_startup(3mrd) or mrd_show(3mrd). This
       data structure contains the element starting address and
       counts for each type of element, which are needed to map an
       absolute element to the correct zero relative address and
       type.

    o  lock The lock argument indicates whether media removal should
       be prevented or allowed.

    o  dev_status - The dev_status is the address of a dev_status_
       t structure, which is used to pass back detailed error
       information in the event of a command failure.