On Fri, 14 Aug 2020, Larry McVoy wrote:
> I'm sure everyone here knows this, but the Cray 1 (I think, the one that
> had what looked like a circular bench seat around the bottom) was
> designed like that because the clock was at the center and the clock
> signal went to all the boards and was right because all the clock lines
> to the boards were the same length.
Yep, timing was everything in those days (and I'm still amazed at the
people who believe that electricity moves at the speed of light).
Wasn't it Grace Hopper who used to demonstrate a nanosecond by holding up
a foot of wire?
Yes. A nanosecond is just over a foot in copper... I used to do high precision timing and we used to make cables specific lengths to bring the on time point of different parts of the signal distribution system into alignment... you could also see how bands or kinks in the cables moved the on time point...
Warner