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From: Michael S <already5chosen@yahoo.com>
Newsgroups: comp.arch
Subject: Re: The Seymour Cray Era of Supercomputers
Date: Mon, 19 May 2025 16:35:37 +0300
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On Sun, 18 May 2025 22:01:19 +0000
mitchalsup@aol.com (MitchAlsup1) wrote:

> On Sun, 18 May 2025 8:33:30 +0000, Michael S wrote:
> 
> > On Sat, 17 May 2025 21:27:04 +0000
> > mitchalsup@aol.com (MitchAlsup1) wrote:
> >  
> >> Did the book relate the story of why CRAY-1 presented a DC-load to
> >> the power supply:: that is, the ECL gates were all of the form
> >> where they would switch 20 ma into either the true or the
> >> complement out- put and thus have no AC energy at the power supply
> >> level ??
> >>
> >> During the CDC 7600 reign, when performing vector calculations,
> >> (even though CDC 7600 was not a vector machine, it could stream
> >> calculations through its execution window at impressive rates);
> >> Certain data bit-patterns in CDC 7600 would cause more Gnd bounce
> >> and Vdd drop than the gates cols accommodate and the machine would
> >> take a data-dependent hard crash.
> >>  
> >
> > Which voltage, current and frequency are we talking about?  
> 
> Vdd and Gnd which fed the integrated logic gates.
> 

My question was about absolute numbers. Volts, amperes, nanoseconds.

> >  
> >> So, Cray got rid of the problem by presenting a DC-load to the
> >> power supply.