Subject: How does the hard drive work?

can someone tell me how the hard drive works in some details? I know there's a head reading the information off the disk and the information is represented by the orientations of the billions of magnetic irons, but that means the head would be very small, at least in a size comparable to one of the magnetic dusts. but it seems that the hard drive head is quite big? did i misunderstand something. how can the head move in a such accuracy that i change the orientation of the particular magnetic dust(s) we want? Can someonev give me more information on the physical aspect of this process?

Re: How does the hard drive work?