alt Hacker NewsIn my first internship, with a hard disk drive company, I learned how to use an Atomic Force Microscope to measure the roughness of the hard drive platter (the disk). The texture variation is in the order of angstroms or nanometers. It’s incredible how the AFM works like the needle of a record player, not via optics, and sensing at the atomic level.
What's the size difference between the AFM needle and the area of stored magnetic flux on a hard drive platter? If you used an AFM as a sort of record player, scanning along lines of little pits, what sort of theoretical information density could be achieved over the whole surface of the disk?