<s>
The	O
VAX	B-Device
9000	I-Device
is	O
a	O
discontinued	O
family	O
of	O
mainframes	B-Architecture
developed	O
and	O
manufactured	O
by	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
using	O
custom	O
ECL-based	O
processors	O
implementing	O
the	O
VAX	B-Device
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
(	O
ISA	O
)	O
.	O
</s>
<s>
Equipped	O
with	O
optional	O
vector	B-Operating_System
processors	I-Operating_System
,	O
they	O
were	O
marketed	O
into	O
the	O
supercomputer	B-Architecture
space	O
as	O
well	O
.	O
</s>
<s>
As	O
with	O
other	O
VAX	B-Device
systems	O
,	O
they	O
were	O
sold	O
with	O
either	O
the	O
VMS	B-Operating_System
or	O
Ultrix	B-Operating_System
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
systems	O
trace	O
their	O
history	O
to	O
DEC	O
's	O
1984	O
licensing	O
of	O
several	O
technologies	O
from	O
Trilogy	O
Systems	O
,	O
who	O
had	O
introduced	O
a	O
new	O
way	O
to	O
densely	O
pack	O
ECL	B-General_Concept
chips	O
into	O
complex	O
modules	O
.	O
</s>
<s>
Development	O
of	O
the	O
9000	O
design	O
began	O
in	O
1986	O
,	O
intended	O
as	O
a	O
replacement	O
for	O
the	O
VAX	B-Device
8800	I-Device
family	O
,	O
at	O
that	O
time	O
the	O
high-end	O
VAX	B-Device
offering	O
.	O
</s>
<s>
DEC	O
intended	O
the	O
9000	O
to	O
allow	O
the	O
company	O
to	O
move	O
back	O
into	O
the	O
mainframe	B-Architecture
market	O
,	O
which	O
it	O
had	O
abandoned	O
starting	O
in	O
1983	O
,	O
as	O
it	O
watched	O
the	O
low	O
end	O
of	O
the	O
computer	O
market	O
being	O
taken	O
over	O
by	O
ever-improving	O
IBM	O
compatible	O
personal	B-Device
computer	I-Device
systems	O
and	O
the	O
new	O
32-bit	O
Unix	B-Device
workstation	I-Device
machines	O
.	O
</s>
<s>
The	O
company	O
invested	O
an	O
estimated	O
$1	O
billion	O
in	O
the	O
development	O
of	O
the	O
9000	O
,	O
in	O
spite	O
of	O
considerable	O
in-company	O
concern	O
about	O
the	O
concept	O
in	O
the	O
era	O
of	O
rapidly	O
improving	O
RISC	B-Architecture
performance	O
.	O
</s>
<s>
Production	O
problems	O
pushed	O
back	O
its	O
release	O
,	O
by	O
which	O
time	O
these	O
fears	O
had	O
come	O
true	O
and	O
newer	O
microprocessors	O
like	O
DEC	O
's	O
own	O
NVAX	B-Device
offered	O
a	O
significant	O
fraction	O
of	O
the	O
9000	O
's	O
performance	O
for	O
a	O
tiny	O
fraction	O
of	O
the	O
price	O
.	O
</s>
<s>
One	O
representative	O
example	O
CPU	B-Device
sits	O
in	O
storage	O
at	O
the	O
Computer	O
History	O
Museum	O
,	O
not	O
on	O
public	O
display	O
.	O
</s>
<s>
The	O
PDP-11	B-Device
was	O
released	O
in	O
1970	O
and	O
continued	O
strong	O
sales	O
that	O
would	O
ultimately	O
reach	O
600,000	O
machines	O
,	O
while	O
their	O
newly	O
introduced	O
VAX-11	B-Device
picked	O
up	O
where	O
the	O
PDP	O
ended	O
and	O
was	O
beginning	O
to	O
make	O
major	O
inroads	O
to	O
IBM	O
's	O
midrange	O
market	O
.	O
</s>
<s>
DEC	O
also	O
introduced	O
their	O
famous	O
VT	B-Device
series	O
computer	B-General_Concept
terminals	I-General_Concept
and	O
a	O
wide	O
variety	O
of	O
other	O
popular	O
peripherals	O
that	O
all	O
generated	O
significant	O
cashflow	O
.	O
</s>
<s>
Through	O
this	O
period	O
,	O
DEC	O
made	O
several	O
attempts	O
to	O
enter	O
the	O
personal	B-Device
computer	I-Device
field	O
,	O
but	O
these	O
all	O
failed	O
.	O
</s>
<s>
Best	O
known	O
among	O
these	O
was	O
the	O
Rainbow	B-Device
100	I-Device
,	O
which	O
aimed	O
to	O
offer	O
the	O
ability	O
to	O
run	O
both	O
MS-DOS	B-Application
and	O
CP/M	B-Application
programs	O
,	O
but	O
instead	O
demonstrated	O
itself	O
incapable	O
of	O
doing	O
either	O
very	O
well	O
while	O
costing	O
about	O
as	O
much	O
as	O
buying	O
two	O
separate	O
machines	O
.	O
</s>
<s>
In	O
one	O
example	O
,	O
their	O
new	O
VAXBI	B-Architecture
Bus	I-Architecture
could	O
not	O
be	O
used	O
by	O
other	O
developers	O
unless	O
they	O
signed	O
a	O
development	O
agreement	O
.	O
</s>
<s>
This	O
was	O
a	O
stark	O
contrast	O
to	O
the	O
Unibus	B-Device
standard	O
of	O
the	O
PDP	O
and	O
earlier	O
VAX	B-Device
machines	O
,	O
which	O
had	O
a	O
thriving	O
market	O
of	O
3rd	O
party	O
products	O
.	O
</s>
<s>
Notable	O
among	O
these	O
was	O
Sun	O
Microsystems	O
,	O
whose	O
Motorola	O
68000-based	O
systems	O
offered	O
performance	O
similar	O
to	O
DEC	O
's	O
VAXstation	B-Device
series	O
while	O
being	O
based	O
on	O
the	O
UNIX	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
This	O
was	O
aided	O
by	O
DEC	O
's	O
own	O
1985	O
decision	O
to	O
abandon	O
the	O
technical	O
market	O
in	O
favor	O
of	O
the	O
higher	O
margins	O
in	O
the	O
data	B-Operating_System
center	I-Operating_System
.	O
</s>
<s>
During	O
the	O
1960s	O
,	O
DEC	O
computers	O
had	O
been	O
built	O
out	O
of	O
individual	O
transistors	B-Application
and	O
began	O
to	O
move	O
to	O
using	O
small	O
scale	O
integration	O
integrated	O
circuits	O
(	O
SSI	O
ICs	O
)	O
.	O
</s>
<s>
These	O
would	O
be	O
built	O
onto	O
a	O
number	O
of	O
circuit	O
boards	O
,	O
which	O
would	O
then	O
be	O
wire	O
wrapped	O
together	O
on	O
a	O
backplane	B-Architecture
to	O
produce	O
the	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	B-Device
)	O
.	O
</s>
<s>
By	O
the	O
early-1970s	O
,	O
small	O
and	O
medium	O
scale	O
integration	O
ICs	O
were	O
being	O
used	O
,	O
and	O
large	O
scale	O
integration	O
(	O
LSI	O
)	O
was	O
allowing	O
simpler	O
CPUs	B-Device
to	O
be	O
implemented	O
in	O
a	O
single	O
IC	O
(	O
or	O
"	O
chip	O
"	O
)	O
.	O
</s>
<s>
By	O
the	O
late	O
1970s	O
,	O
a	O
number	O
of	O
LSI	O
versions	O
of	O
the	O
PDP-11	B-Device
were	O
available	O
,	O
first	O
as	O
multi-chip	O
units	O
like	O
DEC	O
's	O
own	O
LSI-11	O
,	O
and	O
later	O
in	O
single-chip	O
versions	O
like	O
the	O
J-11	B-Device
.	O
</s>
<s>
The	O
VAX	B-Device
was	O
a	O
more	O
complex	O
system	O
,	O
beyond	O
the	O
capabilities	O
of	O
LSI	O
of	O
1970s	O
in	O
a	O
single-chip	O
format	O
.	O
</s>
<s>
Early	O
models	O
resembled	O
the	O
PDP	O
's	O
of	O
the	O
earlier	O
generations	O
,	O
but	O
with	O
multiple	O
LSI	O
chips	O
on	O
printed	O
circuit	O
boards	O
building	O
up	O
the	O
more	O
complex	O
CPU	B-Device
rather	O
than	O
SSI	O
chips	O
on	O
wire-wrapped	O
boards	O
.	O
</s>
<s>
VLSI	O
ICs	O
could	O
hold	O
hundreds	O
of	O
thousands	O
or	O
millions	O
of	O
transistors	B-Application
,	O
enough	O
to	O
implement	O
an	O
entire	O
VAX	B-Device
system	O
on	O
a	O
single	O
chip	O
.	O
</s>
<s>
This	O
led	O
to	O
1985	O
's	O
MicroVAX	B-Device
78032	I-Device
,	O
which	O
implemented	O
a	O
subset	O
of	O
the	O
VAX	B-Device
,	O
but	O
it	O
was	O
clear	O
it	O
would	O
not	O
be	O
long	O
before	O
the	O
"	O
full	O
"	O
VAX	B-Device
would	O
fit	O
on	O
a	O
single	O
chip	O
.	O
</s>
<s>
Remaining	O
relevant	O
to	O
data	B-Operating_System
centers	I-Operating_System
required	O
a	O
new	O
architecture	O
ill-suited	O
to	O
single-chip	O
fabrication	O
.	O
</s>
<s>
At	O
that	O
time	O
,	O
CMOS	B-Device
fabrication	O
typically	O
produced	O
slower	O
ICs	O
than	O
the	O
competing	O
emitter-coupled	B-General_Concept
logic	I-General_Concept
(	O
ECL	B-General_Concept
)	O
system	O
.	O
</s>
<s>
However	O
,	O
ECL	B-General_Concept
’s	O
density	O
was	O
lower	O
,	O
and	O
its	O
feature	O
sizes	O
about	O
a	O
generation	O
behind	O
CMOS	B-Device
.	O
</s>
<s>
DEC	O
had	O
to	O
choose	O
between	O
building	O
either	O
a	O
very	O
fast	O
ECL	B-General_Concept
machine	O
with	O
a	O
high	O
chip	O
count	O
,	O
or	O
a	O
somewhat	O
slower	O
CMOS	B-Device
machine	O
using	O
fewer	O
chips	O
.	O
</s>
<s>
Using	O
ECL	B-General_Concept
was	O
more	O
complex	O
,	O
but	O
consistent	O
with	O
DEC	O
's	O
long	O
history	O
of	O
multi-chip	O
and	O
multi-card	O
CPU	B-Device
designs	O
.	O
</s>
<s>
A	O
related	O
ECL	B-General_Concept
issue	O
was	O
inter-chip	O
wiring	O
proliferation	O
proportional	O
to	O
the	O
massive	O
pin	O
count	O
increase	O
required	O
by	O
modern	O
machines’	O
address	B-General_Concept
space	I-General_Concept
growth	O
.	O
</s>
<s>
In	O
1980	O
,	O
Gene	O
Amdahl	O
formed	O
Trilogy	O
Systems	O
to	O
solve	O
problems	O
in	O
high-performance	O
ECL-based	O
mainframe	B-Architecture
production	O
.	O
</s>
<s>
In	O
contrast	O
to	O
Trilogy	O
's	O
goal	O
of	O
introducing	O
their	O
own	O
plug-compatible	B-Device
mainframes	B-Architecture
and	O
competing	O
with	O
IBM	O
directly	O
,	O
DEC	O
would	O
use	O
similar	O
technology	O
to	O
produce	O
a	O
VAX	B-Device
outperforming	O
IBM	O
's	O
offerings	O
at	O
a	O
lower	O
price	O
point	O
.	O
</s>
<s>
Trilogy	O
's	O
wiring	O
technologies	O
were	O
used	O
to	O
create	O
card-sized	O
"	O
multi-chip	O
units	O
"	O
(	O
MCUs	O
)	O
working	O
together	O
like	O
earlier	O
multi-card	O
CPU	B-Device
designs	O
.	O
</s>
<s>
In	O
the	O
final	O
design	O
,	O
13	O
MCUs	O
formed	O
the	O
CPU	B-Device
.	O
</s>
<s>
While	O
development	O
was	O
ongoing	O
,	O
in	O
late	O
1988	O
IBM	O
introduced	O
its	O
AS/400	B-Device
systems	O
,	O
a	O
new	O
mid-range	O
line	O
that	O
was	O
much	O
more	O
cost-competitive	O
than	O
previous	O
offerings	O
.	O
</s>
<s>
Meanwhile	O
,	O
Sun	O
was	O
introducing	O
their	O
SPARC	B-Architecture
microprocessor	O
which	O
allowed	O
desktop	O
machines	O
to	O
outperform	O
even	O
the	O
fastest	O
of	O
DEC	O
's	O
existing	O
machines	O
.	O
</s>
<s>
This	O
eroded	O
DEC	O
's	O
value	O
in	O
its	O
other	O
traditional	O
market	O
of	O
Unix	B-Application
systems	I-Application
.	O
</s>
<s>
DEC	O
had	O
initially	O
been	O
sceptical	O
of	O
RISC	B-Architecture
,	O
believing	O
it	O
worked	O
on	O
trivial	O
five-line	O
programs	O
but	O
would	O
not	O
be	O
successful	O
in	O
the	O
transaction	B-General_Concept
processing	I-General_Concept
field	O
.	O
</s>
<s>
This	O
opinion	O
was	O
turned	O
upside	O
down	O
in	O
1986	O
when	O
an	O
experimental	O
RISC	B-Architecture
developed	O
at	O
DEC	O
's	O
Western	O
Research	O
Lab	O
was	O
compared	O
head-to-head	O
with	O
the	O
latest	O
VAX	B-Device
8800	I-Device
and	O
outperformed	O
it	O
2-to-1	O
.	O
</s>
<s>
This	O
led	O
to	O
a	O
program	O
to	O
develop	O
a	O
production-quality	O
scalable	O
RISC	B-Architecture
design	O
,	O
which	O
emerged	O
as	O
the	O
DEC	B-Architecture
PRISM	I-Architecture
.	O
</s>
<s>
While	O
the	O
battle	O
between	O
the	O
RISC	B-Architecture
and	O
ECL	B-General_Concept
groups	O
continued	O
,	O
the	O
CMOS	B-Device
team	O
building	O
VAX	B-Device
processors	O
was	O
continuing	O
to	O
improve	O
as	O
well	O
.	O
</s>
<s>
Bob	O
Supnik	O
claims	O
that	O
it	O
was	O
clear	O
to	O
senior	O
technical	O
people	O
as	O
early	O
as	O
1987	O
that	O
the	O
next	O
generation	O
of	O
CMOS	B-Device
chips	O
,	O
the	O
NVAX	B-Device
,	O
would	O
perform	O
as	O
well	O
as	O
the	O
9000	O
by	O
1988	O
,	O
even	O
though	O
the	O
9000	O
was	O
not	O
slated	O
to	O
launch	O
until	O
1989	O
.	O
</s>
<s>
There	O
are	O
several	O
quotes	O
by	O
prominent	O
engineers	O
on	O
the	O
NVAX	B-Device
project	O
that	O
describe	O
Olsen	O
's	O
unwillingness	O
to	O
kill	O
the	O
9000	O
even	O
after	O
being	O
told	O
point-blank	O
that	O
it	O
would	O
not	O
be	O
competitive	O
by	O
the	O
early	O
1990s	O
,	O
and	O
his	O
outright	O
rejection	O
that	O
such	O
a	O
thing	O
was	O
even	O
possible	O
.	O
</s>
<s>
As	O
the	O
company	O
continued	O
to	O
back	O
the	O
9000	O
while	O
it	O
became	O
more	O
and	O
more	O
clear	O
it	O
would	O
not	O
be	O
competitive	O
,	O
various	O
groups	O
within	O
the	O
company	O
began	O
developing	O
RISC-based	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
The	O
unlikely	O
outcome	O
of	O
this	O
was	O
that	O
all	O
of	O
the	O
RISC	B-Architecture
projects	O
were	O
instead	O
killed	O
off	O
with	O
the	O
exception	O
of	O
some	O
ongoing	O
work	O
at	O
the	O
Hudson	O
Fab	O
on	O
a	O
low-end	O
PRISM	O
.	O
</s>
<s>
Comparing	O
it	O
to	O
a	O
low-end	O
IBM	B-Device
3090	I-Device
,	O
IBM	O
's	O
flagship	O
mainframe	B-Architecture
,	O
DEC	O
positioned	O
the	O
machine	O
for	O
transaction	B-General_Concept
processing	I-General_Concept
and	O
high-end	O
database	O
systems	O
.	O
</s>
<s>
In	O
February	O
1991	O
,	O
they	O
announced	O
a	O
low-end	O
version	O
,	O
the	O
Model	O
110	O
at	O
$920	O
,	O
000	O
,	O
appealing	O
to	O
customers	O
looking	O
for	O
CPU	B-Device
power	O
without	O
the	O
need	O
for	O
extensive	O
storage	O
or	O
other	O
options	O
.	O
</s>
<s>
Meanwhile	O
,	O
the	O
engineering	O
team	O
's	O
predictions	O
about	O
the	O
relentless	O
march	O
of	O
CMOS	B-Device
proved	O
true	O
.	O
</s>
<s>
By	O
1991	O
,	O
the	O
NVAX	B-Device
was	O
also	O
on	O
the	O
market	O
,	O
offering	O
roughly	O
the	O
same	O
performance	O
for	O
a	O
tiny	O
fraction	O
of	O
the	O
cost	O
and	O
size	O
.	O
</s>
<s>
At	O
lower	O
performance	O
settings	O
the	O
same	O
design	O
was	O
available	O
in	O
desktop	O
form	O
,	O
outperforming	O
all	O
previous	O
VAX	B-Device
machines	O
.	O
</s>
<s>
The	O
VAX	B-Device
9000	I-Device
was	O
a	O
multiprocessor	B-Operating_System
and	O
supported	O
one	O
,	O
two	O
,	O
three	O
or	O
four	O
CPUs	B-Device
clocked	O
at	O
62.5MHz	O
(	O
16	O
ns	O
cycle	O
time	O
)	O
.	O
</s>
<s>
The	O
system	O
was	O
based	O
around	O
a	O
crossbar	O
switch	O
in	O
the	O
system	O
control	O
unit	O
(	O
SCU	O
)	O
,	O
to	O
which	O
the	O
one	O
to	O
four	O
CPUs	B-Device
,	O
two	O
memory	O
controllers	O
,	O
two	O
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
controllers	O
and	O
a	O
service	O
processor	O
connected	O
.	O
</s>
<s>
I/O	B-General_Concept
was	O
provided	O
by	O
four	O
Extended	O
Memory	O
Interconnect	O
(	O
XMI	O
)	O
buses	O
.	O
</s>
<s>
Each	O
CPU	B-Device
was	O
implemented	O
with	O
13	O
Multi-Chip	O
Units	O
(	O
MCUs	O
)	O
,	O
with	O
each	O
MCU	O
containing	O
several	O
emitter-coupled	B-General_Concept
logic	I-General_Concept
(	O
ECL	B-General_Concept
)	O
macrocell	O
arrays	O
which	O
contained	O
the	O
CPU	B-Device
logic	O
.	O
</s>
<s>
The	O
MCUs	O
were	O
installed	O
into	O
a	O
CPU	B-Device
planar	O
module	O
,	O
which	O
accommodated	O
16	O
MCUs	O
and	O
was	O
24	O
by	O
in	O
size	O
.	O
</s>
<s>
The	O
VAX	B-Device
9000	I-Device
's	O
CPU	B-Device
was	O
coupled	O
with	O
a	O
vector	B-Operating_System
processor	I-Operating_System
with	O
a	O
maximum	O
theoretical	O
performance	O
of	O
125	O
MFLOPS	O
.	O
</s>
<s>
The	O
vector	B-Operating_System
processor	I-Operating_System
circuitry	O
was	O
present	O
in	O
all	O
units	O
shipped	O
and	O
disabled	O
via	O
a	O
software	O
switch	O
on	O
units	O
sold	O
'	O
without	O
 '	O
the	O
vector	B-Operating_System
processor	I-Operating_System
.	O
</s>
<s>
The	O
vector	B-Operating_System
processor	I-Operating_System
was	O
referred	O
to	O
as	O
the	O
V-box	O
,	O
and	O
it	O
was	O
Digital	O
's	O
first	O
ECL	B-General_Concept
implementation	O
of	O
the	O
VAX	B-Device
Vector	O
Architecture	O
.	O
</s>
<s>
The	O
design	O
of	O
the	O
vector	B-Operating_System
processor	I-Operating_System
began	O
in	O
1986	O
,	O
two	O
years	O
after	O
development	O
of	O
the	O
VAX	B-Device
9000	I-Device
CPU	B-Device
had	O
begun	O
.	O
</s>
<s>
The	O
vector	O
register	O
unit	O
,	O
also	O
known	O
as	O
the	O
vector	O
register	O
file	O
,	O
implemented	O
the	O
16	O
vector	O
registers	O
defined	O
by	O
the	O
VAX	B-Device
vector	O
architecture	O
.	O
</s>
<s>
SID	O
(	O
Synthesis	O
of	O
Integral	O
Design	O
)	O
was	O
a	O
logic	O
synthesis	O
program	O
used	O
to	O
generate	O
logic	O
gates	O
for	O
the	O
VAX	B-Device
9000	I-Device
.	O
</s>
<s>
From	O
high-level	O
behavioral	O
and	O
register-transfer	O
level	O
sources	O
,	O
approximately	O
93%	O
of	O
the	O
CPU	B-Device
scalar	O
and	O
vector	O
units	O
,	O
over	O
700,000	O
gates	O
,	O
were	O
synthesized	O
.	O
</s>
<s>
SID	O
was	O
an	O
artificial	B-Application
intelligence	I-Application
rule-based	O
system	O
and	O
expert	B-Application
system	I-Application
with	O
over	O
1000	O
hand-written	O
rules	O
.	O
</s>
<s>
In	O
addition	O
to	O
logic	O
gate	O
creation	O
,	O
SID	O
took	O
the	O
design	O
to	O
the	O
wiring	O
level	O
,	O
allocating	O
loads	O
to	O
nets	O
and	O
providing	O
parameters	O
for	O
place	O
and	O
route	O
CAD	B-Application
tools	O
.	O
</s>
<s>
A	O
complete	O
synthesis	O
run	O
for	O
the	O
VAX	B-Device
9000	I-Device
took	O
3	O
hours	O
.	O
</s>
<s>
Initially	O
it	O
was	O
somewhat	O
controversial	O
but	O
was	O
accepted	O
in	O
order	O
to	O
reduce	O
the	O
overall	O
VAX	B-Device
9000	I-Device
project	O
budget	O
.	O
</s>
<s>
The	O
SID-generated	O
portion	O
of	O
the	O
VAX	B-Device
9000	I-Device
was	O
completed	O
2	O
years	O
ahead	O
of	O
schedule	O
,	O
whereas	O
other	O
areas	O
of	O
the	O
VAX	B-Device
9000	I-Device
development	O
encountered	O
implementation	O
problems	O
,	O
resulting	O
in	O
a	O
much	O
delayed	O
product	O
release	O
.	O
</s>
<s>
Following	O
the	O
VAX	B-Device
9000	I-Device
,	O
SID	O
was	O
never	O
used	O
again	O
.	O
</s>
<s>
The	O
VAX	B-Device
9000	I-Device
Model	O
110	O
was	O
an	O
entry-level	O
model	O
with	O
the	O
same	O
performance	O
as	O
the	O
Model	O
210	O
but	O
had	O
a	O
smaller	O
memory	O
capacity	O
and	O
was	O
bundled	O
with	O
less	O
software	O
and	O
services	O
.	O
</s>
<s>
On	O
22	O
February	O
1991	O
,	O
it	O
was	O
priced	O
from	O
US$920	O
,	O
000	O
,	O
and	O
if	O
fitted	O
with	O
a	O
vector	B-Operating_System
processor	I-Operating_System
,	O
from	O
US$	O
997,000	O
.	O
</s>
<s>
The	O
VAX	B-Device
9000	I-Device
Model	O
210	O
was	O
an	O
entry-level	O
model	O
with	O
one	O
CPU	B-Device
that	O
could	O
be	O
upgraded	O
.	O
</s>
<s>
If	O
a	O
vector	B-Operating_System
processor	I-Operating_System
was	O
present	O
,	O
it	O
was	O
known	O
as	O
the	O
VAX	B-Device
9000	I-Device
Model	O
210VP	O
.	O
</s>
<s>
The	O
VAX	B-Device
9000	I-Device
Model	O
4x0	O
was	O
a	O
multiprocessor	B-Operating_System
capable	O
model	O
,	O
the	O
value	O
of	O
"	O
x	O
"	O
(	O
1	O
,	O
2	O
,	O
3	O
or	O
4	O
)	O
denoting	O
the	O
number	O
of	O
CPUs	B-Device
present	O
.	O
</s>
<s>
These	O
models	O
supported	O
the	O
vector	B-Operating_System
processor	I-Operating_System
,	O
with	O
one	O
vector	B-Operating_System
processor	I-Operating_System
supported	O
per	O
CPU	B-Device
.	O
</s>
<s>
The	O
number	O
of	O
I/O	B-General_Concept
buses	O
supported	O
varied	O
,	O
with	O
the	O
Model	O
410	O
and	O
420	O
supporting	O
two	O
XMI	O
,	O
ten	O
CI	O
and	O
eight	O
VAXBI	B-Architecture
;	O
while	O
the	O
Model	O
430	O
and	O
440	O
supported	O
four	O
XMI	O
,	O
ten	O
CI	O
and	O
14	O
VAXBI	B-Architecture
.	O
</s>
