Le 27/07/2010 13:41, Invisible nous fit lire :
> Oh yes, destruction is good, baby! :-D
> To me, this suggests that the magnetic domains ought to
> be still readable with sufficiently sophisticated equipment.

Probably correct, expensive but correct: if you can get the orientation
of the magnetic platters, you have the data.
They are missing a journey past the curie point so far.

> 
> Also... I thought the platters were glass? Last time I checked, glass
> doesn't bend.

Glass is one solution, other are aluminium (or ceramic).
The video might be with an aluminium platter.
Moreover, given the high deposit on the platters (of specific magnetic &
non-magnetic materials), even a glass platter might be seen as inside a
continuous bag of metal... we only see the external.

And in fact, glass can bend. It's just that it does not like taking too
much stress. If glass was unable to deform, the single song of a bird
would break apart all the windows of every building. And closing a glass
door with energic tamper would also break it everytime. So, glass is
elastic, a bit.

> 
> And finally, how many thousand tonnes of force does it take to bend
> inch-thick steel? And how do you generate those kinds of forces with
> such a tiny machine?

Hydrolic make wonders.
Also, mechanical reduction (a small motor turning with high speed is
reduced to a very slow movement with higher force)
Given the slow move and weak excursion of the pushing cone, I would bet
for a non-reversable gear-set using a worm drive setup.
The same kind of setup which allow a small hand to put the huge tension
on a cord of a guitar.

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