<s>
The	O
IBM	B-Device
303X	I-Device
is	O
a	O
discontinued	O
line	O
of	O
mainframe	B-Architecture
computers	I-Architecture
,	O
the	O
first	O
model	O
of	O
which	O
,	O
the	O
IBM	O
3033	O
Processor	O
,	O
nicknamed	O
"	O
The	O
Big	O
One	O
"	O
,	O
was	O
introduced	O
March	O
25	O
,	O
1977	O
.	O
</s>
<s>
All	O
three	O
303X	B-Device
systems	O
were	O
withdrawn	O
on	O
February	O
5	O
,	O
1985	O
.	O
</s>
<s>
The	O
CPUs	O
feature	O
instruction	B-General_Concept
pipelining	I-General_Concept
,	O
"	O
several	O
instructions	O
can	O
be	O
pre-fetched	O
while	O
one	O
is	O
being	O
executed	O
"	O
.	O
</s>
<s>
"	O
Processor	O
storage	O
...	O
is	O
four-way	O
interleaved	B-General_Concept
"	O
resulting	O
in	O
"	O
a	O
significantly	O
faster	O
data	O
rate	O
than	O
...	O
non-interleaved	O
"	O
.	O
</s>
<s>
The	O
systems	O
consume	O
less	O
than	O
half	O
the	O
floor	O
space	O
of	O
a	O
System/370	B-Device
with	O
an	O
equal	O
amount	O
of	O
computer	O
memory	O
and	O
an	O
identical	O
number	O
of	O
channels	B-Device
because	O
"	O
the	O
channels	B-Device
are	O
physically	O
integrated	O
within	O
the	O
processor	O
mainframe.	O
"	O
</s>
<s>
Each	O
group	O
of	O
six	O
channels	B-Device
has	O
its	O
own	O
microprogrammed	B-Device
channel	O
processor	O
,	O
a	O
System/370	B-Device
-158-type	O
processor	O
running	O
special	O
channel	O
microcode	B-Device
.	O
</s>
<s>
The	O
initial	O
announcement	O
of	O
the	O
3033	O
also	O
introduced	O
new	O
operating	B-General_Concept
system	I-General_Concept
versions	O
"	O
MVS/System	O
Extensions	O
(	O
MVS/SE	O
)	O
and	O
VM/System	O
Extensions	O
(	O
VM/SE	O
)	O
.	O
"	O
</s>
<s>
"	O
A	O
compatible	O
member	O
of	O
the	O
System/370	B-Device
family.	O
"	O
</s>
<s>
"	O
the	O
System/370	B-Device
3033	O
Processor.	O
"	O
</s>
<s>
At	O
this	O
time	O
,	O
other	O
companies	O
,	O
known	O
as	O
plug	B-Device
compatible	I-Device
manufacturers	I-Device
(	O
PCMs	O
)	O
,	O
were	O
competing	O
with	O
IBM	O
by	O
producing	O
IBM-compatible	O
systems	O
.	O
</s>
<s>
By	O
the	O
late	O
1970s	O
and	O
early	O
1980s	O
,	O
patented	O
technology	O
allowed	O
Amdahl	O
IBM-compatible	O
mainframes	B-Architecture
of	O
this	O
era	O
to	O
be	O
completely	O
air-cooled	O
,	O
unlike	O
IBM	O
systems	O
that	O
required	O
chilled	O
water	O
and	O
its	O
supporting	O
infrastructure	O
—	O
the	O
8	O
largest	O
of	O
the	O
18	O
models	O
of	O
the	O
ES/9000	B-Device
systems	O
introduced	O
in	O
1990	O
were	O
water-cooled	O
;	O
the	O
other	O
ten	O
were	O
air-cooled	O
.	O
</s>
<s>
The	O
improvement	O
in	O
Price	O
–	O
performance	O
of	O
the	O
303X	B-Device
models	O
created	O
volume	O
of	O
orders	O
sufficient	O
to	O
cause	O
a	O
backlog	O
.	O
</s>
<s>
Magnuson	O
Computer	O
Systems	O
also	O
produced	O
the	O
M80	O
System/370	B-Device
-compatible	O
computer	O
system	O
between	O
1975	O
and	O
1980	O
.	O
</s>
<s>
One	O
group	O
of	O
six	O
channels	B-Device
is	O
standard	O
.	O
</s>
<s>
This	O
group	O
of	O
channels	B-Device
contains	O
one	O
byte	O
multiplexer	O
and	O
five	O
block	O
multiplexer	O
channels	B-Device
.	O
</s>
<s>
An	O
optional	O
channel-to-channel	B-Device
adapter	I-Device
(	O
CTCA	O
)	O
is	O
available	O
.	O
</s>
<s>
The	O
3031	O
is	O
supported	O
by	O
MVS	O
,	O
OS/VS1	O
SVS	O
,	O
VM/370	B-Application
,	O
ACP	B-Application
,	O
and	O
TSS/370	B-Application
,	O
and	O
DOS/VS	B-Application
,	O
the	O
last	O
of	O
which	O
is	O
not	O
mentioned	O
as	O
supported	O
by	O
the	O
other	O
303X	B-Device
models	O
.	O
</s>
<s>
One	O
group	O
of	O
six	O
channels	B-Device
is	O
standard	O
;	O
this	O
can	O
optionally	O
be	O
expanded	O
by	O
the	O
addition	O
of	O
another	O
six	O
.	O
</s>
<s>
Each	O
group	O
of	O
channels	B-Device
contains	O
one	O
byte	O
multiplexer	O
and	O
five	O
block	O
multiplexer	O
channels	B-Device
.	O
</s>
<s>
An	O
optional	O
channel-to-channel	B-Device
adapter	I-Device
(	O
CTCA	O
)	O
is	O
available	O
.	O
</s>
<s>
The	O
3032	O
is	O
supported	O
by	O
MVS	O
,	O
OS/VS1	O
SVS	O
,	O
VM/370	B-Application
,	O
ACP	B-Application
,	O
and	O
TSS/370	B-Application
.	O
</s>
<s>
Two	O
groups	O
of	O
six	O
channels	B-Device
are	O
standard	O
;	O
this	O
can	O
optionally	O
be	O
expanded	O
by	O
the	O
addition	O
of	O
another	O
six	O
.	O
</s>
<s>
Each	O
group	O
of	O
channels	B-Device
contains	O
one	O
byte	O
multiplexer	O
and	O
five	O
block	O
multiplexer	O
channels	B-Device
.	O
</s>
<s>
An	O
optional	O
channel	O
group	O
is	O
available	O
consisting	O
of	O
either	O
four	O
block	O
multiplexer	O
channels	B-Device
or	O
one	O
byte	O
multiplexer	O
and	O
three	O
block	O
multiplexers	O
.	O
</s>
<s>
The	O
3033	O
is	O
supported	O
by	O
MVS	O
,	O
OS/VS1	O
SVS	O
,	O
VM/370	B-Application
,	O
and	O
ACP	B-Application
.	O
</s>
<s>
Each	O
shipped	O
the	O
following	O
quarter	O
;	O
both	O
were	O
withdrawn	O
in	O
1985	O
,	O
along	O
with	O
the	O
other	O
303X	B-Device
offerings	O
.	O
</s>
<s>
The	O
3033	O
was	O
later	O
made	O
available	O
in	O
attached-processor	B-Operating_System
(	O
AP	O
)	O
and	O
multiprocessor	B-Operating_System
(	O
MP	O
)	O
dyadic	O
configurations	O
.	O
</s>
