Megaprocessor - built from individual transistors

[Paul Koning]

> On Jun 25, 2015, at 7:16 AM, David Griffith <dave at 661.org> wrote:
> 
> ...
> I don't think thatt making the flip-chips double-sided will be desirable.  I want to shrink the machine and minimize any need to reengineer the backplane.  By the way, can the backplane of a straight-eight be realized as a PCB?  

Of course.  The only reason a PCB backplane would be an issue is if there are signal integrity concerns, but at DEC speeds that’s not going to be a problem.  Especially if what you’re aiming to replace is wire wrap which is in general worse at signal integrity than PCB.  Now if you were looking to replace the chassis wiring of a 6600 with a PCB, that would be a different matter, then you’d want to be a bit more cautious.  Even then it’s clearly doable, if you use transmission line design on the PCB signals.

	paul