This superb slideshow at Tom’s Hardware shows the facilities and processes by which the hard drives we so often take for granted are created with unbelievable precision. The Springtown facility in Ireland is one of their primary sites. The yellow light is, I’m guessing, a wavelength that doesn’t affect the raw wafers’ surface. The processes are explained in some detail although some technical knowledge is necessary to get the full effect. Still, how about this for breaking it down:
If the read/write head were a Boeing 747, and the hard-disk platter were the surface of the Earth:
The head would fly at Mach 800
At less than one centimeter from the ground
And count every blade of grass
Making fewer than 10 unrecoverable counting errors in an area equivalent to all of Ireland.
The whole tour is very interesting, and the photos by Matthieu Lamelot are excellent.