A Cray SuperComputer Comes to the University of Toronto



By Andrew Reeves-Hall


The Cray X-MP/22 manufactured by Cray Research Incorporated
(CRI) of Minneapolis, Minnesota was delivered and installed at
the U of Toronto this September. The Cray is a well respected
computer - mainly for its extremely fast rate of mathematical
floating-pointcalculation. As the university states in its
July/August computer magazine "ComputerNews", the Cray\'s "level
of performance should enable researchers with large computational
requirements at the university of Toronto and other Ontario
universities to compete effectively against the best in the world
in their respective
fields."

The Cray X-MP/22 has two Central Processing Units (CPUs) -
the first \'2\' in the \'22\'. The Cray operates at a clock rate of
105 MHz (the regular, run-of-the-mill IBMPC has a clock rate of
4.77 MHz). By quick calculations, you would be led to believe the
Cray is only about 20 times faster that the PC. Obviously, this
is not the case. The Cray handles data considerably differently
than the PC. The Cray\'s circuits permit an array of data (known
as a \'vector\') to be processes as a SINGLE entity. So, where the
IBMPC may require several clock cycles to multiply two numbers,
the Cray performs everything in one clock cycle. This power is
measured in Millions of Floating Point Operations Per Second
(MFLOPS) - which is to say the rate at which floating-point
operations can be performed. The Cray MFLOPS vary as it does many
activities, but a rate of up to 210 MFLOPS (per CPU) can be
achieved.

The second \'2\' in the X-MP/22 title refers to the two
million 64-bit words (16Mb) of shared central memory. This can be
expanded to four million words in the future if the need arises.
But it doesn\'t stop there! The Cray can pipe information back and
forth between the CPU memory and the Input/Output Subsystem
(IOS). The IOS then takes it upon itself the store the
information in any of the four storage devices: i) one of the
four 1200 Mb disk drives (at a rate of 5.9Mb every second), ii)
one of two standard 200ips 6250bpi tape drives, iii) a Solid
State Storage Device (SSD) (which is much like a 128Mb RAM
Disk!), or iv) through to a front-end computer (the U of T uses
both the IBM4381 and a DEC VAX). These computers would be
programmed (usually in FORTRAN) and the information passed onto
the Cray. The results would then be transfered back to the front
end computers.

The 4 year old Cray was bought used from the California NASA
research centre where it was used in aerodynamic calculations.
This means less cost to buy it and the assurance that it has been
\'burned in\'. In case you wanted one for yourself, the U of T was
able to purchase the Cray for the low-low price of $12 million.
Over the next five years, the University predicts the total cost
will probably be $25 million when maintenance, staff and other
costs are taken into consideration. To help out, the Ontario
Government put in $10 million. By doing this, all other Ontario
University researchers are assured of access at a reduced cost.
By the way, to buy time on the system, it\'ll cost you $2000 per
hour. But Ontario researchers only have to pay 7% of that - $140
per hour. Their first commercial customer is OMNIBUS Graphics of
Toronto who plan to use the Cray in the graphic videos. If you
saw the movie \'The Last Starfighter\', you will have already
experienced the graphic capabilites of the Cray (remember the
some of the space scenes!). The Cray did all of the calculations
required for those scenes and let another graphics computer to do
the menial task of drawing the lines and filling with the
calculated colour.

There is so much to talk about when the word \'Cray\' pops to
mind! If you are seriously interested in this amazing computer
and/or you are interested in purchasing time on the system,
please contact the people below:

The Centre for Large Scale Computation at the U of T
Llyod Parker, Director
978-8255

Facilities Manager
Dr. Edmund West
978-4085

Supercomputer User\'s Group (for University Researchers, etc)
Professor Philip Kromberg
978-4971