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From: heisterb@uxe.cso.uiuc.edu.UUCP
Newsgroups: comp.misc
Subject: Re: IBM mainframe for sale
Message-ID: <48800003@uxe.cso.uiuc.edu>
Date: Thu, 1-Oct-87 14:13:00 EDT
Article-I.D.: uxe.48800003
Posted: Thu Oct  1 14:13:00 1987
Date-Received: Sat, 3-Oct-87 10:29:48 EDT
References: <4WALT@MAINE>
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Nf-ID: #R:<4WALT@MAINE>:-13:uxe.cso.uiuc.edu:48800003:000:1444
Nf-From: uxe.cso.uiuc.edu!heisterb    Oct  1 13:13:00 1987



[ diet Coke - Just for the chemistry of it! ]

A CRAY is like an iceberg, what you see is a small part of what there
really is.  First power supply.  Something like a gizillion amps of 3
phase 220 (or is it 400V?).  This runs a motor generator that produces
400Hz 3 phase (don't know the voltage, it's not in my book) that goes
to the main power controller.  You never see the motor generator, it's
usually hidden in a basement.  There's separate power controllers for
the mainframe, the ios, and the ssd.  The bench around the mainframe and
other parts has additional power regulators for each section (12 for the
mainframe).  So it doesn't just plug into a wall.  I'm guessing that the
power consumption of an X-MP/48, IOS, and 128MW SSD is about 500-700kVA.

As for cooling, the above system uses two 25 ton condensers.  The main-
frame et. al. is cooled by freon running through copper or aluminum
tubing, with heat exchange from freon to water in the condensers.  Then
of course there's the chillers on the roof for the water.

It costs an unbelievable amount to run a CRAY.  It's an entirely different
class of environmental support than most mainframes.  But it's worth it!

The above information from "down the street" and the
"CRAY X-MP Four-Processor Mainframe Reference Manual" with the cute
orange cover sheet!

DJ Heisterberg
National Center for Supercomputing Applications
heisterb@uxe.cso.uiuc.edu
13004@ncsa[a|b].ncsa.uiuc.edu