Re: material of HDs?

[Rubywand <rubywand@swbell.net>]

Adalbert Goertz writes ...
> 
> re
> I think glass and/or aluminum for hard disk platters and
> plastic and aluminum for CDs.  The aluminum in the CD
> is a very thin disc that does the actual storing.  The
> plastic is just to protect it and make it stiff enough for
> humans and the CD player or CD drive motor to handle
> it.
 ....

     CD's do not depend upon magnetic storage; so, there does not seem to any
need for them to contain magnetic materials. CD's are read by laser beams.
The aluminum or whatever inside the plastic probably has little tiny blips
created by a laser during recording which are detected during playback.



Rubywand