Re: gEDA-user: PCB suggestion

["harry eaton" <bumpelo@xxxxxxxxxxx>]

> Am 06.01.2005 um 01:10 schrieb harry eaton:
> > The Pentium processor chip has only 7 wiring layers; it must be of
> > "medium
> > to low" complexity!
> >
> > Eight copper layers is not presently a serious limitation to users;
>
> Eight copper layers does not mean eight wiring layers, You often have
> several power planes.

I guess that means there is no power routing in the Pentium processor since
it only has 7 wiring layers. I wonder why they get so hot that they need
fans when there are no power connections.  My point is it's usually possible
to route a board with far fewer layers than are actually used. It's
definitely harder to route that way, but usually possible. Signals integrity
may be lower, but (as in IC design) good enough.

I'm pleased to see that some folks have used the 8 copper layers available,
I hadn't heard of any specific examples before now. Since I now know there
are some fairly high-end-complexity users out there I will extend the copper
layer support to 16 soon; it's really not that hard.

For what it's worth, I never liked the layer grouping concept but I've
preserved it for full backward compatibility for those who have used it. It
was one of the few part of Thomas' original work that I didn't care for.

harry