CD-ROM drives operate in the following manner:
      
       
       1.) The laser diode emits a low-energy infra-red beam toward a reflecting mirror.
       
       2.) The servo motor, on command from the microprocessor, positions the beam onto the 
           correct track on the CD-ROM by moving the reflecting mirror.
       
       3.) When the beam hits the disc, its refracted light is gathered and focused through      
           the first lens beneath the platter, bounced off the mirror, and sent toward the 
           beam splitter.
       
       4.) The beam splitter directs returning laser light toward another focusing lens.
       
       5.) The last lens directs the light beam to aphoto detector that converts the light 
           into electric impulses.
       
       6.) These incoming impulses are decoded by the microprocessor and sent along to the 
           host computer as data. 

                                                                                done