[rescue] mysterious hard hangs, two different sun4m's

[Francisco Javier Mesa-Martinez]

> On Tue, 3 Sep 2002, Francisco Javier Mesa-Martinez wrote:
> 
> > Theoretically the PC case is supposed to be a Faraday box, the fact that
> > it picked up the E field from a nearby powergrid would be enough to allow
> > you to report the manufacturer to the FCC. This is why I am always tempted
> > to report Fry's whenever I see one of those transparet FeeCee cases on
> > display....
> 
> Maybe I'm wrong, but isn't a device to accept any interference, but
> generate none of its own?
> 

A simple conducting cage can be used to shield electronic equipment.
Basically this allows to cancel all electric fields outside the box, the
side effect is that it also cancels internal electric fields to the
outside world.

Faraday cages were the thought experiment for modern electric isulation.

The problem is that most devices in the super-KHz ranges do generate a
hefty amount or radio activity. Thus shielding is quite mandatory, however
American engineering regulations are usually very lax, thus the fact that
you can actually market cheap plastic computer cases, that will most
likely hold 1/2GHz processors. Modern computer systems due to the
extremely large number of traces in their boards (as well as large
switching components like the processor) are incredible radio noise
generators. They are also more sensitive to noise interferece... and now
that we have 2.4GHz processors, in a wireless world that runs mostly in
the 2.4GHz spectrum....

Then we have the poor heat conductivity that those transparent cases do
have. Thus putting a thermally sensitive device, which generates a LOT of
heat, inside a nice insulator is not a good idea IMHO. Why am I amazed by
all this? Well when I went to Fry's I saw these things for the first time,
in the price tag they had written "Great for Overcloking!". So the people
who buy these transparent cases, are not only laughing at most laws of
Electrodinamics, but they are also pissing on the laws of Thermodynamics. 
That is why they deserve the boot in the head! And Fry's too, not only for
that but for many other reasons. :-)