<s>
The	O
Cray-3	B-Device
was	O
a	O
vector	B-Operating_System
supercomputer	B-Architecture
,	O
Seymour	O
Cray	O
's	O
designated	O
successor	O
to	O
the	O
Cray-2	B-Device
.	O
</s>
<s>
The	O
system	O
was	O
one	O
of	O
the	O
first	O
major	O
applications	O
of	O
gallium	O
arsenide	O
(	O
GaAs	O
)	O
semiconductors	O
in	O
computing	O
,	O
using	O
hundreds	O
of	O
custom	O
built	O
ICs	O
packed	O
into	O
a	O
CPU	B-General_Concept
.	O
</s>
<s>
The	O
design	O
goal	O
was	O
performance	O
around	O
16	O
GFLOPS	O
,	O
about	O
12	O
times	O
that	O
of	O
the	O
Cray-2	B-Device
.	O
</s>
<s>
Work	O
started	O
on	O
the	O
Cray-3	B-Device
in	O
1988	O
at	O
Cray	O
Research	O
's	O
(	O
CRI	O
)	O
development	O
labs	O
in	O
Chippewa	O
Falls	O
,	O
Wisconsin	O
.	O
</s>
<s>
To	O
focus	O
the	O
teams	O
,	O
the	O
Cray-3	B-Device
effort	O
was	O
moved	O
to	O
a	O
new	O
lab	O
in	O
Colorado	O
Springs	O
,	O
Colorado	O
later	O
that	O
year	O
.	O
</s>
<s>
Shortly	O
thereafter	O
,	O
the	O
corporate	O
headquarters	O
in	O
Minneapolis	O
decided	O
to	O
end	O
work	O
on	O
the	O
Cray-3	B-Device
in	O
favor	O
of	O
another	O
design	O
,	O
the	O
Cray	B-Device
C90	I-Device
.	O
</s>
<s>
In	O
1989	O
the	O
Cray-3	B-Device
effort	O
was	O
spun	O
off	O
to	O
a	O
newly	O
formed	O
company	O
,	O
Cray	O
Computer	O
Corporation	O
(	O
CCC	O
)	O
.	O
</s>
<s>
With	O
the	O
delivery	O
of	O
the	O
first	O
Cray-3	B-Device
,	O
Seymour	O
Cray	O
immediately	O
moved	O
on	O
to	O
the	O
similar-but-improved	O
Cray-4	B-Device
design	O
,	O
but	O
the	O
company	O
went	O
bankrupt	O
before	O
it	O
was	O
completely	O
tested	O
.	O
</s>
<s>
The	O
Cray-3	B-Device
was	O
Cray	O
's	O
last	O
completed	O
design	O
;	O
with	O
CCC	O
's	O
bankruptcy	O
,	O
he	O
formed	O
SRC	O
Computers	O
to	O
concentrate	O
on	O
parallel	O
designs	O
,	O
but	O
died	O
in	O
a	O
car	O
accident	O
in	O
1996	O
before	O
this	O
work	O
was	O
delivered	O
.	O
</s>
<s>
Seymour	O
Cray	O
began	O
the	O
design	O
of	O
the	O
Cray-3	B-Device
in	O
1985	O
,	O
as	O
soon	O
as	O
the	O
Cray-2	B-Device
reached	O
production	O
.	O
</s>
<s>
For	O
the	O
Cray-3	B-Device
,	O
he	O
decided	O
to	O
set	O
an	O
even	O
higher	O
performance	O
improvement	O
goal	O
,	O
an	O
increase	O
of	O
12x	O
over	O
the	O
Cray-2	B-Device
.	O
</s>
<s>
Cray	O
had	O
always	O
attacked	O
the	O
problem	O
of	O
increased	O
speed	O
with	O
three	O
simultaneous	O
advances	O
;	O
more	O
execution	B-General_Concept
units	I-General_Concept
to	O
give	O
the	O
system	O
higher	O
parallelism	B-Operating_System
,	O
tighter	O
packaging	B-Algorithm
to	O
decrease	O
signal	O
delays	O
,	O
and	O
faster	O
components	O
to	O
allow	O
for	O
a	O
higher	O
clock	O
speed	O
.	O
</s>
<s>
For	O
the	O
Cray-2	B-Device
,	O
he	O
introduced	O
a	O
novel	O
3D-packaging	O
system	O
for	O
its	O
integrated	O
circuits	O
to	O
allow	O
higher	O
densities	O
,	O
and	O
it	O
appeared	O
that	O
there	O
was	O
some	O
room	O
for	O
improvement	O
in	O
this	O
process	O
.	O
</s>
<s>
This	O
would	O
demand	O
the	O
processor	O
be	O
able	O
to	O
fit	O
into	O
a	O
block	O
,	O
about	O
that	O
of	O
the	O
Cray-2	B-Device
CPU	B-General_Concept
.	O
</s>
<s>
For	O
a	O
12x	O
performance	O
increase	O
,	O
the	O
packaging	B-Algorithm
alone	O
would	O
not	O
be	O
enough	O
,	O
the	O
circuits	O
on	O
the	O
chips	O
themselves	O
would	O
also	O
have	O
to	O
speed	O
up	O
.	O
</s>
<s>
The	O
Cray-2	B-Device
appeared	O
to	O
be	O
pushing	O
the	O
limits	O
of	O
the	O
speed	O
of	O
silicon-based	O
transistors	B-Application
at	O
4.1ns	O
(	O
244MHz	O
)	O
,	O
and	O
it	O
did	O
not	O
appear	O
that	O
anything	O
more	O
than	O
another	O
2x	O
would	O
be	O
possible	O
.	O
</s>
<s>
Cray	O
had	O
intended	O
to	O
use	O
gallium	O
arsenide	O
circuitry	O
in	O
the	O
Cray-2	B-Device
,	O
which	O
would	O
not	O
only	O
offer	O
much	O
higher	O
switching	O
speeds	O
but	O
also	O
used	O
less	O
energy	O
and	O
thus	O
ran	O
cooler	O
as	O
well	O
.	O
</s>
<s>
At	O
the	O
time	O
the	O
Cray-2	B-Device
was	O
being	O
designed	O
,	O
the	O
state	O
of	O
GaAs	O
manufacturing	O
simply	O
was	O
not	O
up	O
to	O
the	O
task	O
of	O
supplying	O
a	O
supercomputer	B-Architecture
.	O
</s>
<s>
One	O
of	O
the	O
problems	O
with	O
the	O
Cray-2	B-Device
had	O
been	O
poor	O
multiprocessing	O
performance	O
due	O
to	O
limited	O
bandwidth	O
between	O
the	O
processors	O
,	O
and	O
to	O
address	O
this	O
the	O
Cray-3	B-Device
would	O
adopt	O
the	O
much	O
faster	O
architecture	O
used	O
in	O
the	O
Cray	B-Device
Y-MP	I-Device
.	O
</s>
<s>
The	O
Cray-3	B-Device
was	O
originally	O
slated	O
for	O
delivery	O
in	O
1991	O
.	O
</s>
<s>
This	O
was	O
during	O
a	O
time	O
when	O
the	O
supercomputer	B-Architecture
market	O
was	O
rapidly	O
shrinking	O
from	O
50%	O
annual	O
growth	O
in	O
1980	O
,	O
to	O
10%	O
in	O
1988	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
Cray	O
Research	O
was	O
also	O
working	O
on	O
the	O
Y-MP	O
,	O
a	O
faster	O
multi-processor	O
version	O
of	O
the	O
system	O
architecture	O
tracing	O
its	O
ancestry	O
to	O
the	O
original	O
Cray-1	B-Device
.	O
</s>
<s>
In	O
order	O
to	O
focus	O
the	O
Y-MP	O
and	O
Cray-3	B-Device
groups	O
,	O
and	O
with	O
Cray	O
's	O
personal	O
support	O
,	O
the	O
Cray-3	B-Device
project	O
moved	O
to	O
a	O
new	O
research	O
center	O
in	O
Colorado	O
Springs	O
.	O
</s>
<s>
With	O
only	O
25	O
Cray-2s	B-Device
sold	O
,	O
management	O
decided	O
that	O
the	O
Cray-3	B-Device
should	O
be	O
put	O
on	O
"	O
low	O
priority	O
"	O
development	O
.	O
</s>
<s>
NCAR	O
's	O
version	O
was	O
configured	O
with	O
4	O
processors	O
and	O
a	O
128MWord	O
(	O
64-bit	B-Device
words	O
,	O
1GB	O
)	O
common	O
memory	O
.	O
</s>
<s>
In	O
service	O
,	O
the	O
static	B-Architecture
RAM	I-Architecture
proved	O
to	O
be	O
problematic	O
.	O
</s>
<s>
Seven	O
system	O
cabinets	O
,	O
or	O
"	O
tanks	O
"	O
,	O
serial	O
numbers	O
S1	O
to	O
S7	O
,	O
were	O
built	O
for	O
Cray-3	B-Device
machines	O
.	O
</s>
<s>
Most	O
were	O
for	O
smaller	O
two-CPU	O
machines	O
.	O
</s>
<s>
Three	O
of	O
the	O
smaller	O
tanks	O
were	O
used	O
on	O
the	O
Cray-4	B-Device
project	O
,	O
essentially	O
a	O
Cray-3	B-Device
with	O
64	O
faster	O
CPUs	O
running	O
at	O
1ns	O
(	O
1GHz	O
)	O
and	O
packed	O
into	O
an	O
even	O
smaller	O
space	O
.	O
</s>
<s>
Another	O
was	O
used	O
for	O
the	O
Cray-3/SSS	B-Device
project	O
.	O
</s>
<s>
The	O
failure	O
of	O
the	O
Cray-3	B-Device
was	O
in	O
large	O
part	O
due	O
to	O
the	O
changing	O
political	O
and	O
technical	O
climate	O
.	O
</s>
<s>
The	O
machine	O
was	O
being	O
designed	O
during	O
the	O
collapse	O
of	O
the	O
Warsaw	O
Pact	O
and	O
ending	O
of	O
the	O
cold	B-Application
war	I-Application
,	O
which	O
led	O
to	O
a	O
massive	O
downsizing	O
in	O
supercomputer	B-Architecture
purchases	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
the	O
market	O
was	O
increasingly	O
investing	O
in	O
massively	B-Operating_System
parallel	I-Operating_System
(	O
MP	O
or	O
MPP	O
)	O
designs	O
.	O
</s>
<s>
Cray	O
was	O
critical	O
of	O
this	O
approach	O
,	O
and	O
was	O
quoted	O
by	O
The	O
Wall	O
Street	O
Journal	O
as	O
saying	O
that	O
MPP	O
systems	O
had	O
not	O
yet	O
proven	O
their	O
supremacy	O
over	O
vector	B-Operating_System
computers	I-Operating_System
,	O
noting	O
the	O
difficulty	O
many	O
users	O
have	O
had	O
programming	O
for	O
large	O
parallel	B-Operating_System
machines	I-Operating_System
.	O
</s>
<s>
The	O
Cray-3	B-Device
system	O
architecture	O
comprised	O
a	O
foreground	O
processing	O
system	O
,	O
up	O
to	O
16	O
background	O
processors	O
and	O
up	O
to	O
2	O
gigawords	O
(	O
16	O
GB	O
)	O
of	O
common	O
memory	O
.	O
</s>
<s>
The	O
foreground	O
system	O
was	O
dedicated	O
to	O
input/output	B-General_Concept
and	O
system	O
management	O
.	O
</s>
<s>
It	O
included	O
a	O
32-bit	O
processor	O
and	O
four	O
synchronous	O
data	O
channels	O
for	O
mass	B-Device
storage	I-Device
and	O
network	O
devices	O
,	O
primarily	O
via	O
HiPPI	B-Architecture
channels	O
.	O
</s>
<s>
The	O
computation	O
section	O
performed	O
64-bit	B-Device
scalar	O
,	O
floating	B-Algorithm
point	I-Algorithm
and	O
vector	B-Operating_System
arithmetic	I-Operating_System
.	O
</s>
<s>
Common	O
memory	O
consisted	O
of	O
silicon	O
CMOS	B-Device
SRAM	B-Architecture
,	O
organized	O
into	O
octants	O
of	O
64	O
banks	O
each	O
,	O
with	O
up	O
to	O
eight	O
octants	O
possible	O
.	O
</s>
<s>
The	O
word	O
size	O
was	O
64-bits	B-Device
plus	O
eight	O
error-correction	B-Error_Name
bits	O
,	O
and	O
total	O
memory	O
bandwidth	O
was	O
rated	O
at	O
128	O
gigabytes	O
per	O
second	O
.	O
</s>
<s>
As	O
with	O
previous	O
designs	O
,	O
the	O
core	O
of	O
the	O
Cray-3	B-Device
consisted	O
of	O
a	O
number	O
of	O
modules	O
,	O
each	O
containing	O
several	O
circuit	O
boards	O
packed	O
with	O
parts	O
.	O
</s>
<s>
In	O
order	O
to	O
increase	O
density	O
,	O
the	O
individual	O
GaAs	O
chips	O
were	O
not	O
packaged	B-Algorithm
,	O
and	O
instead	O
several	O
were	O
mounted	O
directly	O
with	O
ultrasonic	O
gold	O
bonding	O
to	O
a	O
board	O
approximately	O
square	O
.	O
</s>
<s>
These	O
submodules	O
were	O
then	O
stacked	O
four-deep	O
and	O
,	O
as	O
in	O
the	O
Cray-2	B-Device
,	O
wired	O
to	O
each	O
other	O
to	O
make	O
a	O
3D	O
circuit	O
.	O
</s>
<s>
Unlike	O
the	O
Cray-2	B-Device
,	O
the	O
Cray-3	B-Device
modules	O
also	O
included	O
edge	O
connectors	O
.	O
</s>
<s>
Even	O
with	O
this	O
advanced	O
packaging	B-Algorithm
the	O
circuit	O
density	O
was	O
low	O
even	O
by	O
1990s	O
standards	O
,	O
at	O
about	O
96,000	O
gates	O
per	O
cubic	O
inch	O
.	O
</s>
<s>
The	O
bricks	O
were	O
immersed	O
in	O
liquid	O
fluorinert	O
for	O
cooling	O
,	O
as	O
in	O
the	O
Cray-2	B-Device
.	O
</s>
<s>
All	O
in	O
all	O
,	O
the	O
Cray-3	B-Device
was	O
considerably	O
smaller	O
than	O
the	O
Cray-2	B-Device
,	O
itself	O
relatively	O
small	O
compared	O
to	O
other	O
supercomputers	B-Architecture
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
system	O
cabinet	O
,	O
a	O
Cray-3	B-Device
system	O
also	O
needed	O
one	O
or	O
two	O
(	O
depending	O
on	O
number	O
of	O
processors	O
)	O
system	O
control	O
pods	O
(	O
or	O
"	O
C-Pods	O
"	O
)	O
,	O
square	O
and	O
high	O
,	O
containing	O
power	O
and	O
cooling	O
control	O
equipment	O
.	O
</s>
<s>
The	O
following	O
possible	O
Cray-3	B-Device
configurations	O
were	O
officially	O
specified	O
:	O
</s>
<s>
The	O
Cray-3	B-Device
ran	O
the	O
Colorado	O
Springs	O
Operating	B-General_Concept
System	I-General_Concept
(	O
CSOS	O
)	O
which	O
was	O
based	O
upon	O
Cray	O
Research	O
's	O
UNICOS	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
version	O
5.0	O
.	O
</s>
<s>
A	O
major	O
difference	O
between	O
CSOS	O
and	O
UNICOS	B-Operating_System
was	O
that	O
CSOS	O
was	O
ported	O
to	O
standard	O
C	B-Language
with	O
all	O
PCC	B-Application
extensions	O
that	O
were	O
used	O
in	O
UNICOS	B-Operating_System
removed	O
.	O
</s>
<s>
Much	O
of	O
the	O
software	O
available	O
under	O
the	O
Cray-3	B-Device
was	O
derived	O
from	O
Cray	O
Research	O
and	O
included	O
for	O
instance	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
,	O
vectorizing	O
FORTRAN	B-Application
and	O
C	B-Language
compilers	O
,	O
NFS	B-Protocol
and	O
a	O
TCP/IP	B-Protocol
stack	I-Protocol
.	O
</s>
