Re: The Seymour Cray Era of Supercomputers

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