[0x0203]

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?

[cornstalks]

This is an advertisement, but it's one of the few I actually enjoy watching, and it suggests a track is "2500 times smaller than a human hair" which puts an upper bound on the size of a bit: https://www.youtube.com/watch?v=ZXs_9OXRnQo

This doesn't answer your question but your question made me think of this and I thought I'd share for anyone else.

[hbarka]

That video is a perfect description. Hard disk drives are incredible machines, going through many steps to produce the platter. The flying head is also fascinating. To this day I have full working hard drives over over twenty years old, while my SSDs have gone kaput.

The Bay Area used to be the center of these companies’ manufacturing and I was there when they literally unbolted the Varian sputter machines from my company to ship to Malaysia. The likes of Seagate, Western Digital, Conner, Quantum, Maxtor, Micropolis, Hitachi, Fujitsu, IBM, Read-Rite. Also Iomega in Utah. They were all here. They all left practically overnight. They were executive decisions. It was a shocking move and the whole history would make a good documentary or movie.

[MobiusHorizons]

If they are using the typical human hair = one thou, then the 2500 is suspiciously close to the conversion between inches and millimeters times a power of ten. I get 10 microns