A system and method are disclosed for load-sharing in reliable server pools which provide access to legacy servers. An electron beam is deflected by passage through a magnetic or electric field to be measured and is allowed to pass through a deflection electrode to thereby be deflected in a direction perpendicular to the magnetic or electric field to be measured. Also, existence of a false broken concave condition can be diagnosed by movements of the concave responsive to operation of the driver. Finally, utilize a display unit to project said corrected coordinate model to front of said driver, so that projection position of said coordinate model overlaps said position field of view of said driver. Another aspect includes calculating a synthesized degree of relevance by synthesizing the plurality of degrees of relevance of the second electronic file to the first electronic file.