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

[Francisco Javier Mesa-Martinez]

On Wed, 4 Sep 2002, Tim H. wrote:

> On Tue, 3 Sep 2002 22:02:09 -0700 (PDT)
> Francisco Javier Mesa-Martinez <lefa at cats.ucsc.edu> 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.... 
> 
> Actually, the FCC doesn't care if your PC picks up noise, it only cares
> if it broadcasts noise.  THe official language is something to the
> effect "(1)this device may not cause harmful interference (2) this
> device must accept any interference received including interference that
> may cause undesired operation.  FCC doesn't regulate receivers, other
> than who may listen in on what frequencies, they regulate transmitters.

As I explained in a previous post, in order to shield the internal E
fields of a device you usually have to use a device that also negates
external E fields. Hence if you have an switching electromagnetic device
that does pick up external fields, that means that your shielding is not
guaranteed to also cancel the internal radio harmonics to outside
receptors. Simple electromagnetic theory really.... That is why those
cases can not be FCC compliant, hence the owner of such device is in
theory breaking the law. But then again I am talking to a list that
includes people with class B machines, whith theoretically are also
illegal to own at home. But at least these are real machines :-).