On Aug 21, 2006, at 12:19 PM, Stuart Brorson wrote:
I believe that back in the 70s DEC used to use two layer boards with PWR and GND run on busses layed out on a rectilinear grid. Signal traces were on top (IIRC) and PWR/GND on teh bottom. The DIPs were layed out in rectangular rows following teh same grid. Fingers would extend from the PWR and GND busses to each DIP to feed its power/ground pins.
This is true of *some* DEC boards but definitely not all. I see it on about 1/3 of them. That scheme didn't seem to last long before they went to multilayer boards with embedded power/ground layers. (I have ~200 qbus, unibus, and omnibus boards here; I hack on 'em all the time)
-Dave -- Dave McGuire Cape Coral, FL _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user