Where are Rare Earth Magnets Located in Computers?

Motors and generators are where you'll find them. And maybe in the read head of your hard drive. Rare earth magnets can be much smaller than alnico of ferrite magnets.

I have some doubts that the read/write head of a HDD is equiped with a PM.

As far know the head is a miniature coil used to polarize the material of the disc by writing and to get the pulse geberated by the polarized disc island by readind. But of course as usual I may be wrong.

Benbenben's got it. Moving coil motor with RE magnets moves HDD swing arm which has the read/write heads at the far end. I believe the platter spin motor (brushless DC) may also contain small RE magnets.

********** DON'T TAKE APART A GOOD DRIVE! *************

If you have an old HDD which is toast, take it apart to see how it works. RE magnets are very powerful so be careful. For a real treat, take a look at the read/write heads under a microscope.

Yes, controlling the read write head in HDDs

You will also find a set in your CD/DVD player/burner. Back when I was doing audio repair I had dozens holding notes up over my bench.