<s>
The	O
CDC	B-Device
6000	I-Device
series	I-Device
is	O
a	O
discontinued	O
family	O
of	O
mainframe	B-Architecture
computers	I-Architecture
manufactured	O
by	O
Control	O
Data	O
Corporation	O
in	O
the	O
1960s	O
.	O
</s>
<s>
It	O
consisted	O
of	O
the	O
CDC	O
6200	O
,	O
CDC	O
6300	O
,	O
CDC	O
6400	O
,	O
CDC	O
6500	O
,	O
CDC	B-Device
6600	I-Device
and	O
CDC	O
6700	O
computers	O
,	O
which	O
were	O
all	O
extremely	O
rapid	O
and	O
efficient	O
for	O
their	O
time	O
.	O
</s>
<s>
Each	O
is	O
a	O
large	O
,	O
solid-state	O
,	O
general-purpose	O
,	O
digital	O
computer	O
that	O
performs	O
scientific	O
and	O
business	O
data	O
processing	O
as	O
well	O
as	O
multiprogramming	O
,	O
multiprocessing	B-Operating_System
,	O
Remote	B-Protocol
Job	I-Protocol
Entry	I-Protocol
,	O
time-sharing	B-General_Concept
,	O
and	O
data	B-General_Concept
management	I-General_Concept
tasks	O
under	O
the	O
control	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
called	O
SCOPE	B-Operating_System
(	O
Supervisory	O
Control	O
Of	O
Program	O
Execution	O
)	O
.	O
</s>
<s>
By	O
1970	O
there	O
also	O
was	O
a	O
time-sharing	B-General_Concept
oriented	O
operating	B-General_Concept
system	I-General_Concept
named	O
KRONOS	B-Operating_System
.	O
</s>
<s>
They	O
were	O
part	O
of	O
the	O
first	O
generation	O
of	O
supercomputers	B-Architecture
.	O
</s>
<s>
The	O
CDC	B-Device
6000	I-Device
series	I-Device
computers	O
are	O
composed	O
of	O
four	O
main	O
functional	O
devices	O
:	O
</s>
<s>
The	O
6000	O
series	O
uses	O
"	O
reduced	B-Architecture
instruction	I-Architecture
set	I-Architecture
"	O
(	O
RISC	B-Architecture
)	O
many	O
years	O
before	O
such	O
a	O
term	O
was	O
invented	O
,	O
and	O
has	O
a	O
distributed	O
architecture	O
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
is	O
a	O
single	O
CPU	O
with	O
10	O
functional	O
units	O
that	O
can	O
operate	O
in	O
parallel	O
,	O
each	O
working	O
on	O
an	O
instruction	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Certain	O
features	O
and	O
nomenclature	O
had	O
also	O
been	O
used	O
in	O
the	O
earlier	O
CDC	B-Device
3000	I-Device
series	I-Device
:	O
</s>
<s>
The	O
name	O
COMPASS	B-Language
was	O
used	O
by	O
CDC	O
for	O
the	O
assembly	B-Language
languages	I-Language
on	O
both	O
families	O
.	O
</s>
<s>
The	O
name	O
SCOPE	B-Operating_System
was	O
used	O
for	O
its	O
operating	B-General_Concept
system	I-General_Concept
implementations	O
on	O
the	O
3000	B-Device
and	O
6000	O
series	O
.	O
</s>
<s>
The	O
only	O
currently	O
(	O
as	O
of	O
2018	O
)	O
running	O
CDC	B-Device
6000	I-Device
series	I-Device
machine	O
,	O
a	O
6500	O
,	O
has	O
been	O
restored	O
by	O
Living	O
Computers	O
:	O
Museum	O
+	O
Labs	O
It	O
was	O
built	O
in	O
1967	O
and	O
used	O
by	O
Purdue	O
University	O
until	O
1989	O
when	O
it	O
was	O
decommissioned	O
and	O
then	O
given	O
to	O
the	O
Chippewa	O
Falls	O
Museum	O
of	O
Industry	O
and	O
Technology	O
before	O
being	O
purchased	O
by	O
Paul	O
Allen	O
for	O
LCM+L	O
.	O
</s>
<s>
The	O
first	O
member	O
of	O
the	O
CDC	B-Device
6000	I-Device
series	I-Device
was	O
the	O
supercomputer	B-Architecture
CDC	B-Device
6600	I-Device
,	O
designed	O
by	O
Seymour	O
Cray	O
and	O
James	O
E	O
.	O
Thornton	O
in	O
Chippewa	O
Falls	O
,	O
Wisconsin	O
.	O
</s>
<s>
It	O
was	O
introduced	O
in	O
September	O
1964	O
and	O
performs	O
up	O
to	O
three	O
million	O
instructions	O
per	O
second	O
,	O
three	O
times	O
faster	O
than	O
the	O
IBM	B-Device
Stretch	I-Device
,	O
the	O
speed	O
champion	O
for	O
the	O
previous	O
couple	O
of	O
years	O
.	O
</s>
<s>
It	O
remained	O
the	O
fastest	O
machine	O
for	O
five	O
years	O
until	O
the	O
CDC	B-Device
7600	I-Device
was	O
launched	O
.	O
</s>
<s>
Attaching	O
a	O
second	O
system	O
configured	O
without	O
a	O
Central	O
Processor	O
(	O
numbered	O
6416	O
and	O
identified	O
as	O
"	O
Augmented	O
I/O	B-General_Concept
Buffer	O
and	O
Control	O
)	O
to	O
the	O
first	O
;	O
the	O
combined	O
total	O
effectively	O
was	O
20	O
peripheral	O
and	O
control	O
processors	O
with	O
24	O
channels	B-Device
,	O
and	O
the	O
purpose	O
was	O
to	O
support	O
additional	O
peripherals	O
and	O
"	O
significantly	O
increase	O
the	O
multiprogramming	O
and	O
batch	O
job	O
processing	O
of	O
the	O
6000	O
series.	O
"	O
</s>
<s>
In	O
all	O
the	O
CDC	B-Device
6000	I-Device
series	I-Device
computers	O
,	O
the	O
central	O
processor	O
communicates	O
with	O
around	O
seven	O
simultaneously	O
active	O
programs	O
(	O
jobs	B-General_Concept
)	O
,	O
which	O
reside	O
in	O
central	O
memory	O
.	O
</s>
<s>
Instructions	O
from	O
these	O
programs	O
are	O
read	O
into	O
the	O
central	O
processor	B-General_Concept
registers	I-General_Concept
and	O
are	O
executed	O
by	O
the	O
central	O
processor	O
at	O
scheduled	O
intervals	O
.	O
</s>
<s>
An	O
extended	O
core	O
storage	O
unit	O
(	O
ECS	O
)	O
provides	O
additional	O
memory	O
storage	O
and	O
enhances	O
the	O
powerful	O
computing	O
capabilities	O
of	O
the	O
CDC	B-Device
6000	I-Device
series	I-Device
computers	O
.	O
</s>
<s>
While	O
nominally	O
slower	O
than	O
CM	O
,	O
ECS	O
included	O
a	O
buffer	O
(	O
cache	B-General_Concept
)	O
that	O
in	O
some	O
applications	O
gave	O
ECS	O
better	O
performance	O
than	O
CM	O
.	O
</s>
<s>
Note	O
that	O
in	O
the	O
CDC	B-Device
6000	I-Device
architecture	O
,	O
the	O
central	O
processing	O
unit	O
performs	O
no	O
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
operations	O
.	O
</s>
<s>
Input/Output	B-General_Concept
is	O
totally	O
asynchronous	O
,	O
and	O
performed	O
by	O
peripheral	O
processors	O
.	O
</s>
<s>
The	O
eight	O
X	O
registers	O
are	O
each	O
60	B-Device
bits	I-Device
long	O
,	O
and	O
used	O
for	O
most	O
data	O
manipulation	O
—	O
both	O
integer	O
and	O
floating	B-Algorithm
point	I-Algorithm
.	O
</s>
<s>
The	O
eight	O
B	O
registers	O
are	O
18	B-General_Concept
bits	I-General_Concept
long	O
,	O
and	O
generally	O
used	O
for	O
indexing	O
and	O
address	O
storage	O
.	O
</s>
<s>
Register	B-General_Concept
B0	O
is	O
hard-wired	O
to	O
always	O
return	O
0	O
.	O
</s>
<s>
By	O
software	O
convention	O
,	O
register	B-General_Concept
B1	O
is	O
generally	O
set	O
to	O
1	O
.	O
</s>
<s>
The	O
eight	O
18-bit	B-General_Concept
A	O
registers	O
are	O
'	O
coupled	O
 '	O
to	O
their	O
corresponding	O
X	O
registers	O
:	O
setting	O
an	O
address	O
into	O
any	O
of	O
registers	O
A1	O
through	O
A5	O
causes	O
a	O
memory	O
load	O
of	O
the	O
contents	O
of	O
that	O
address	O
into	O
the	O
corresponding	O
X	O
registers	O
.	O
</s>
<s>
Registers	O
A0	O
and	O
X0	O
are	O
not	O
coupled	O
in	O
this	O
way	O
,	O
so	O
can	O
be	O
used	O
as	O
scratch	B-General_Concept
registers	I-General_Concept
.	O
</s>
<s>
Instructions	O
are	O
either	O
15	O
or	O
30	O
bits	O
long	O
,	O
so	O
there	O
can	O
be	O
up	O
to	O
four	O
instructions	O
per	O
60-bit	B-Device
word	O
.	O
</s>
<s>
A	O
60-bit	B-Device
word	O
can	O
contain	O
any	O
combination	O
of	O
15-bit	O
and	O
30-bit	O
instructions	O
that	O
fit	O
within	O
the	O
word	O
,	O
but	O
a	O
30-bit	O
instruction	O
can	O
not	O
wrap	O
to	O
the	O
next	O
word	O
.	O
</s>
<s>
The	O
op	B-Language
codes	I-Language
are	O
six	O
bits	O
long	O
.	O
</s>
<s>
The	O
remainder	O
of	O
the	O
instruction	O
is	O
either	O
three	O
three-bit	O
register	B-General_Concept
fields	O
(	O
two	O
operands	O
and	O
one	O
result	O
)	O
,	O
or	O
two	O
registers	O
with	O
an	O
18-bit	B-General_Concept
immediate	O
constant	O
.	O
</s>
<s>
All	O
instructions	O
are	O
'	O
register	B-General_Concept
to	O
register	B-General_Concept
 '	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
following	O
COMPASS	B-Language
(	O
assembly	B-Language
language	I-Language
)	O
code	O
loads	O
two	O
values	O
from	O
memory	O
,	O
performs	O
a	O
60-bit	B-Device
integer	O
add	O
,	O
then	O
stores	O
the	O
result	O
:	O
</s>
<s>
Depending	O
on	O
instruction	O
type	O
,	O
an	O
instruction	O
can	O
take	O
anywhere	O
from	O
a	O
five	O
clock	O
cycles	O
for	O
18-bit	B-General_Concept
integer	O
arithmetic	O
to	O
as	O
many	O
as	O
68	O
clock	O
cycles	O
(	O
60-bit	B-Device
population	O
count	O
)	O
.	O
</s>
<s>
Thus	O
the	O
CDC	O
6500	O
can	O
nearly	O
double	O
the	O
computational	O
throughput	O
of	O
the	O
machine	O
,	O
although	O
the	O
I/O	B-General_Concept
throughput	O
is	O
still	O
limited	O
by	O
the	O
speed	O
of	O
external	O
I/O	B-General_Concept
devices	I-General_Concept
served	O
by	O
the	O
same	O
10	O
PPs/12	O
Channels	B-Device
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
computer	O
,	O
like	O
the	O
CDC	O
6400	O
,	O
has	O
just	O
one	O
central	O
processor	O
.	O
</s>
<s>
The	O
function	O
units	O
provided	O
are	O
:	O
branch	O
,	O
Boolean	O
,	O
shift	O
,	O
long	O
integer	O
add	O
,	O
floating-point	B-Algorithm
add	O
,	O
floating-point	B-Algorithm
divide	O
,	O
two	O
floating-point	B-Algorithm
multipliers	O
,	O
and	O
two	O
increment	O
(	O
18-bit	B-General_Concept
integer	O
add	O
)	O
units	O
.	O
</s>
<s>
Functional	O
unit	O
latencies	O
are	O
between	O
three	O
clock	O
cycles	O
for	O
increment	O
add	O
and	O
29	O
clock	O
cycles	O
for	O
floating-point	B-Algorithm
divide	O
.	O
</s>
<s>
The	O
6600	O
processor	O
can	O
issue	O
a	O
new	O
instruction	O
every	O
clock	O
cycle	O
,	O
assuming	O
that	O
various	O
processor	O
(	O
functional	O
unit	O
,	O
register	B-General_Concept
)	O
resources	O
were	O
available	O
.	O
</s>
<s>
Also	O
contributing	O
to	O
keeping	O
the	O
issue	O
rate	O
high	O
is	O
an	O
instruction	O
stack	O
,	O
which	O
caches	B-General_Concept
the	O
contents	O
of	O
eight	O
instruction	B-Language
words	I-Language
(	O
32	O
short	O
instructions	O
or	O
16	O
long	O
instructions	O
,	O
or	O
a	O
combination	O
)	O
.	O
</s>
<s>
Floating-point	B-Algorithm
additions	O
are	O
fairly	O
fast	O
at	O
11	O
clock	O
cycles	O
,	O
however	O
floating-point	B-Algorithm
multiplication	O
is	O
very	O
slow	O
at	O
57	O
clock	O
cycles	O
.	O
</s>
<s>
Thus	O
its	O
floating	B-Algorithm
point	I-Algorithm
speed	O
will	O
depend	O
heavily	O
on	O
the	O
mix	O
of	O
operations	O
and	O
can	O
be	O
under	O
200	O
kFLOPS	O
.	O
</s>
<s>
Floating-point	B-Algorithm
additions	O
take	O
four	O
clock	O
cycles	O
,	O
and	O
floating-point	B-Algorithm
multiplications	O
take	O
10	O
clocks	O
(	O
but	O
there	O
are	O
two	O
multiply	O
functional	O
units	O
,	O
so	O
two	O
operations	O
can	O
be	O
processing	O
at	O
the	O
same	O
time	O
.	O
)	O
</s>
<s>
The	O
6600	O
can	O
therefore	O
have	O
a	O
peak	O
floating	B-Algorithm
point	I-Algorithm
speed	O
of	O
2-3	O
MFLOPS	O
.	O
</s>
<s>
One	O
is	O
a	O
CDC	O
6400/CDC	O
6500	O
central	O
processor	O
with	O
the	O
unified	O
arithmetic	O
section	O
;	O
the	O
other	O
is	O
the	O
more	O
efficient	O
CDC	B-Device
6600	I-Device
central	O
processor	O
.	O
</s>
<s>
The	O
combination	O
makes	O
the	O
CDC	O
6700	O
the	O
fastest	O
and	O
the	O
most	O
powerful	O
of	O
the	O
CDC	B-Device
6000	I-Device
series	I-Device
.	O
</s>
<s>
(	O
They	O
are	O
somewhat	O
similar	O
to	O
CDC	B-Device
160A	I-Device
minicomputers	O
,	O
sharing	O
the	O
12-bit	O
word	O
length	O
and	O
portions	O
of	O
the	O
instruction	O
set	O
.	O
)	O
</s>
<s>
While	O
the	O
PPs	O
were	O
designed	O
as	O
an	O
interface	O
to	O
the	O
12	O
I/O	B-Device
channels	I-Device
,	O
portions	O
of	O
the	O
Chippewa	B-Operating_System
Operating	I-Operating_System
System	I-Operating_System
(	O
COS	O
)	O
,	O
and	O
systems	O
derived	O
from	O
it	O
,	O
e.g.	O
,	O
SCOPE	B-Operating_System
,	O
MACE	O
,	O
KRONOS	B-Operating_System
,	O
NOS	B-Operating_System
,	O
and	O
NOS/BE	B-Operating_System
,	O
run	O
on	O
the	O
PPs	O
.	O
</s>
<s>
Only	O
the	O
PPs	O
have	O
access	O
to	O
the	O
channels	B-Device
and	O
can	O
perform	O
input/output	B-General_Concept
:	O
the	O
transfer	O
of	O
information	O
between	O
central	O
memory	O
and	O
peripheral	O
devices	O
such	O
as	O
disks	B-Device
and	O
magnetic	O
tape	O
units	O
.	O
</s>
<s>
They	O
relieve	O
the	O
central	O
processor	O
of	O
all	O
input/output	B-General_Concept
tasks	O
,	O
so	O
that	O
it	O
can	O
perform	O
calculations	O
while	O
the	O
peripheral	O
processors	O
are	O
engaged	O
in	O
input/output	B-General_Concept
and	O
operating	B-General_Concept
system	I-General_Concept
functions	O
.	O
</s>
<s>
Much	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
ran	O
on	O
the	O
PPs	O
,	O
thus	O
leaving	O
the	O
full	O
power	O
of	O
the	O
Central	O
Processor	O
available	O
for	O
user	O
programs	O
.	O
</s>
<s>
Special	O
instructions	O
perform	O
data	O
transfer	O
between	O
processor	O
memory	O
and	O
,	O
via	O
the	O
channels	B-Device
,	O
peripheral	O
devices	O
at	O
up	O
to	O
1μs	O
per	O
word	O
.	O
</s>
<s>
The	O
peripheral	O
processors	O
are	O
collectively	O
implemented	O
as	O
a	O
barrel	B-Operating_System
processor	I-Operating_System
.	O
</s>
<s>
They	O
are	O
a	O
loose	O
predecessor	O
of	O
bus	O
mastering	O
or	O
direct	B-General_Concept
memory	I-General_Concept
access	I-General_Concept
.	O
</s>
<s>
Instructions	O
use	O
a	O
6-bit	O
op	B-Language
code	I-Language
,	O
thus	O
leaving	O
6	O
bits	O
for	O
an	O
operand	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
to	O
combine	O
the	O
next	O
word	O
's	O
12	O
bits	O
,	O
to	O
form	O
an	O
18-bit	B-General_Concept
address	O
(	O
the	O
size	O
needed	O
to	O
access	O
the	O
full	O
131,072	O
words	O
of	O
Central	O
Memory	O
)	O
.	O
</s>
<s>
In	O
addition	O
to	O
communication	O
between	O
peripheral	O
devices	O
and	O
peripheral	O
processors	O
,	O
communication	O
takes	O
place	O
between	O
the	O
computer	O
operator	O
and	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
This	O
is	O
made	O
possible	O
by	O
the	O
computer	B-Device
console	I-Device
,	O
which	O
had	O
two	O
CRT	B-Device
screens	I-Device
.	O
</s>
<s>
(	O
See	O
front	B-Device
panel	I-Device
for	O
an	O
example	O
.	O
)	O
</s>
<s>
The	O
console	O
screens	O
are	O
calligraphic	O
,	O
not	O
raster	B-Algorithm
based	O
.	O
</s>
<s>
DSD	O
displays	O
information	O
about	O
the	O
system	O
and	O
the	O
jobs	B-General_Concept
in	O
process	O
.	O
</s>
<s>
The	O
console	O
also	O
includes	O
a	O
keyboard	O
through	O
which	O
the	O
operator	O
can	O
enter	O
requests	O
to	O
modify	O
stored	O
programs	O
and	O
display	O
information	O
about	O
jobs	B-General_Concept
in	O
or	O
awaiting	O
execution	O
.	O
</s>
<s>
A	O
full-screen	O
editor	O
,	O
called	O
O26	B-Application
(	O
after	O
the	O
IBM	O
model	O
026	O
key	B-Device
punch	I-Device
,	O
with	O
the	O
first	O
character	O
made	O
alphabetic	O
due	O
to	O
operating	B-General_Concept
system	I-General_Concept
restrictions	O
)	O
,	O
can	O
be	O
run	O
on	O
the	O
operator	O
console	O
.	O
</s>
<s>
This	O
text	B-Application
editor	I-Application
appeared	O
in	O
1967	O
—	O
which	O
made	O
it	O
one	O
of	O
the	O
first	O
full-screen	O
editors	O
.	O
</s>
<s>
(	O
Unfortunately	O
,	O
it	O
took	O
CDC	O
another	O
15	O
years	O
to	O
offer	O
FSE	O
,	O
a	O
full-screen	O
editor	O
for	O
normal	O
time-sharing	B-General_Concept
users	O
on	O
CDCs	O
Network	O
Operating	B-General_Concept
System	I-General_Concept
.	O
)	O
</s>
<s>
These	O
included	O
BAT	O
(	O
a	O
baseball	O
game	O
)	O
,	O
KAL	O
(	O
a	O
kaleidoscope	B-Application
)	O
,	O
DOG	O
(	O
Snoopy	B-Application
flying	O
his	O
doghouse	O
across	O
the	O
screens	O
)	O
,	O
ADC	O
(	O
Andy	O
Capp	O
strutting	O
across	O
the	O
screens	O
)	O
,	O
EYE	O
(	O
changes	O
the	O
screens	O
into	O
giant	O
eyeballs	O
,	O
then	O
winks	O
them	O
)	O
,	O
PAC	O
(	O
a	O
Pac-Man-like	O
game	O
)	O
,	O
a	O
lunar	O
lander	O
simulator	O
,	O
and	O
more	O
.	O
</s>
<s>
The	O
minimum	O
hardware	O
requirements	O
of	O
a	O
CDC	B-Device
6000	I-Device
series	I-Device
computer	O
system	O
consists	O
of	O
the	O
computer	O
,	O
including	O
32,768	O
words	O
of	O
central	O
memory	O
storage	O
,	O
any	O
combination	O
of	O
disks	B-Device
,	O
disk	B-Device
packs	O
,	O
or	O
drums	O
to	O
provide	O
24	O
million	O
characters	O
of	O
mass	O
storage	O
,	O
a	O
punched	B-Device
card	I-Device
reader	I-Device
,	O
punched	B-Device
card	I-Device
punch	I-Device
,	O
printer	O
with	O
controllers	O
,	O
and	O
two	O
7-track	O
magnetic	O
tape	O
units	O
.	O
</s>
<s>
Larger	O
systems	O
could	O
be	O
obtained	O
by	O
including	O
optional	O
equipment	O
such	O
as	O
additional	O
central	O
memory	O
,	O
extended	O
core	O
storage	O
(	O
ECS	O
)	O
,	O
additional	O
disk	B-Device
or	O
drum	O
units	O
,	O
card	B-Device
readers	I-Device
,	O
punches	B-Device
,	O
printers	O
,	O
and	O
tape	O
units	O
.	O
</s>
<s>
Graphic	O
plotters	B-Operating_System
and	O
microfilm	O
recorders	O
were	O
also	O
available	O
.	O
</s>
<s>
CDC	O
405	O
Card	B-Device
Reader	I-Device
-	O
Unit	O
reads	O
80-column	O
cards	O
at	O
1200	O
cards	O
a	O
minute	O
and	O
51-column	O
cards	O
at	O
1600	O
cards	O
per	O
minute	O
.	O
</s>
<s>
CDC	O
6676	O
Communications	O
Multiplexer	O
-	O
supported	O
up	O
to	O
64	O
asynchronous	O
data	O
connections	O
up	O
to	O
300bit/s	O
each	O
for	O
timesharing	B-General_Concept
access	O
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
was	O
the	O
flagship	O
.	O
</s>
<s>
The	O
CDC	O
6500	O
was	O
a	O
dual	O
CPU	O
6400	O
,	O
with	O
two	O
CPUs	O
but	O
only	O
one	O
set	O
of	O
I/O	B-General_Concept
PPs	O
,	O
designed	O
for	O
computation-bound	O
problems	O
.	O
</s>
<s>
The	O
CDC	O
6416	O
was	O
an	O
upgrade	O
that	O
could	O
be	O
added	O
to	O
a	O
6000	O
series	O
machine	O
;	O
it	O
added	O
an	O
extra	O
PPU	O
bank	O
,	O
giving	O
a	O
total	O
of	O
20	O
PPUs	O
and	O
24	O
channels	B-Device
,	O
designed	O
for	O
significantly	O
improved	O
I/O	B-General_Concept
performance	O
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
was	O
the	O
flagship	O
mainframe	B-Architecture
supercomputer	B-Architecture
of	O
the	O
6000	O
series	O
of	O
computer	O
systems	O
manufactured	O
by	O
Control	O
Data	O
Corporation	O
.	O
</s>
<s>
Generally	O
considered	O
to	O
be	O
the	O
first	O
successful	O
supercomputer	B-Architecture
,	O
it	O
outperformed	O
its	O
fastest	O
predecessor	O
,	O
the	O
IBM	B-Device
7030	I-Device
Stretch	I-Device
,	O
by	O
a	O
factor	O
of	O
three	O
.	O
</s>
<s>
With	O
performance	O
of	O
up	O
to	O
threemegaFLOPS	O
,	O
the	O
CDC	B-Device
6600	I-Device
,	O
of	O
which	O
about	O
100	O
were	O
sold	O
,	O
was	O
the	O
world	O
's	O
fastest	O
computer	O
from	O
1964	O
to	O
1969	O
,	O
when	O
it	O
relinquished	O
that	O
status	O
to	O
its	O
successor	O
,	O
the	O
CDC	B-Device
7600	I-Device
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
anticipated	O
the	O
RISC	B-Architecture
design	O
philosophy	O
and	O
,	O
unusually	O
,	O
employed	O
a	O
ones'-complement	O
representation	O
of	O
integers	O
.	O
</s>
<s>
The	O
CDC	B-Device
6600	I-Device
was	O
also	O
the	O
first	O
widespread	O
computer	O
to	O
include	O
a	O
Load	B-Architecture
–	I-Architecture
store	I-Architecture
architecture	I-Architecture
,	O
with	O
the	O
writing	O
to	O
its	O
address	B-General_Concept
registers	I-General_Concept
triggering	O
memory	O
load	O
or	O
store	O
of	O
data	O
from	O
its	O
data	O
registers	O
.	O
</s>
<s>
The	O
first	O
CDC	B-Device
6600s	I-Device
were	O
delivered	O
in	O
1965	O
to	O
the	O
Livermore	O
and	O
Los	O
Alamos	O
National	O
Labs	O
(	O
managed	O
by	O
the	O
University	O
of	O
California	O
)	O
.	O
</s>
<s>
The	O
first	O
delivery	O
outside	O
the	O
US	O
went	O
to	O
CERN	O
laboratory	O
near	O
Geneva	O
,	O
Switzerland	B-Protocol
,	O
where	O
it	O
was	O
used	O
to	O
analyse	O
the	O
two	O
to	O
three	O
million	O
photographs	O
of	O
bubble-chamber	B-Algorithm
tracks	O
that	O
CERN	O
experiments	O
were	O
producing	O
every	O
year	O
.	O
</s>
<s>
In	O
1966	O
another	O
CDC	B-Device
6600	I-Device
was	O
delivered	O
to	O
the	O
Lawrence	O
Radiation	O
Laboratory	O
,	O
part	O
of	O
the	O
University	O
of	O
California	O
at	O
Berkeley	O
,	O
where	O
it	O
was	O
used	O
for	O
the	O
analysis	O
of	O
nuclear	O
events	O
photographed	O
inside	O
the	O
Alvarez	O
bubble	B-Algorithm
chamber	I-Algorithm
.	O
</s>
<s>
A	O
CDC	B-Device
6600	I-Device
is	O
on	O
display	O
at	O
the	O
Computer	O
History	O
Museum	O
in	O
Mountain	O
View	O
,	O
California	O
.	O
</s>
<s>
The	O
CDC	O
6400	O
,	O
a	O
member	O
of	O
the	O
CDC	B-Device
6000	I-Device
series	I-Device
,	O
was	O
a	O
mainframe	B-Architecture
computer	I-Architecture
made	O
by	O
Control	O
Data	O
Corporation	O
in	O
the	O
1960s	O
.	O
</s>
<s>
The	O
central	O
processing	O
unit	O
was	O
architecturally	O
compatible	O
with	O
the	O
CDC	B-Device
6600	I-Device
.	O
</s>
<s>
Memory	O
,	O
peripheral	O
processor-based	O
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
,	O
and	O
peripherals	O
were	O
otherwise	O
identical	O
to	O
the	O
6600	O
.	O
</s>
<s>
In	O
1966	O
,	O
the	O
Computing	O
Center	O
(	O
)	O
of	O
the	O
RWTH	O
Aachen	O
University	O
acquired	O
a	O
CDC	O
6400	O
,	O
the	O
first	O
Control	O
Data	O
supercomputer	B-Architecture
in	O
Germany	O
and	O
the	O
second	O
one	O
in	O
Europe	O
after	O
the	O
European	O
Organization	O
for	O
Nuclear	O
Research	O
(	O
CERN	O
)	O
.	O
</s>
<s>
It	O
served	O
the	O
entire	O
university	O
also	O
by	O
64	O
remote-line	O
teletypes	O
(	O
TTY	O
)	O
until	O
it	O
was	O
replaced	O
by	O
a	O
CDC	B-Device
Cyber	I-Device
175	O
computer	O
in	O
1976	O
.	O
</s>
<s>
The	O
CDC	O
6500	O
,	O
which	O
features	O
a	O
dual	O
CPU	O
6400	O
,	O
is	O
the	O
third	O
supercomputer	B-Architecture
in	O
the	O
6000	O
series	O
manufactured	O
by	O
the	O
Control	O
Data	O
Corporation	O
and	O
designed	O
by	O
supercomputer	B-Architecture
pioneer	O
Seymour	O
Cray	O
.	O
</s>
<s>
Michigan	O
State	O
University	O
-	O
bought	O
in	O
1968	O
,	O
meant	O
to	O
replace	O
its	O
CDC	B-Device
3600	I-Device
,	O
and	O
it	O
was	O
the	O
only	O
academic	O
mainframe	B-Architecture
on	O
campus	O
.	O
</s>
