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 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.