Supercomputers, fishing for information

Chuck Guzis cclist at
Sun Nov 6 12:46:03 CST 2016

On 11/06/2016 09:18 AM, ethan at wrote:
>> But smaller than the Crays of the era. If it doesn't run on 400Hz,
>> it's a 'mini' supercomputer.
> Hmmm I knew the earlier Crays often had motor generator setups and
> such but I thoght that was just for power filtering and maybe
> flywheels for ups setups. Didn't know they were 400hz! Odd!

Not at all--that goes back at least to the 1960s.  Consider the CDC
mainframes--MG sets providing 3-phase 400Hz power to variac-regulated
3-phase fullwave rectifier setups.  The ripple frequency is 2400Hz and
has a very high DC component.

This is a very sensible arrangement, as the power supplies need not be
tailored to a specific line voltage or  frequency.

I'm somewhat surprised that no one talks much about cooling systems on
supercomputers, be it forced air or liquid nitrogen.  Both Cray and CDC
spent a fair amount of time and money on getting cooling to their big

How about cooling towers for the chilled water supply?


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