<s>
The	O
IBM	B-Device
System/360	I-Device
Model	I-Device
91	I-Device
was	O
announced	O
in	O
1964	O
as	O
a	O
competitor	O
to	O
the	O
CDC	B-Device
6600	I-Device
.	O
</s>
<s>
Functionally	O
,	O
the	O
Model	O
91	O
ran	O
like	O
any	O
other	O
large-scale	O
System/360	B-Application
,	O
but	O
the	O
internal	O
organization	O
was	O
the	O
most	O
advanced	O
of	O
the	O
System/360	B-Application
line	O
,	O
and	O
it	O
was	O
the	O
first	O
IBM	O
computer	O
to	O
support	O
out-of-order	B-General_Concept
instruction	I-General_Concept
execution	I-General_Concept
.	O
</s>
<s>
It	O
ran	O
OS/360	B-Application
as	O
its	O
operating	O
system	O
.	O
</s>
<s>
The	O
floating-point	B-General_Concept
unit	I-General_Concept
made	O
heavy	O
use	O
of	O
instruction	B-General_Concept
pipelining	I-General_Concept
and	O
was	O
the	O
first	O
implementation	O
of	O
Tomasulo	B-General_Concept
's	I-General_Concept
algorithm	I-General_Concept
.	O
</s>
<s>
It	O
was	O
also	O
one	O
of	O
the	O
first	O
computers	O
to	O
utilize	O
multi-channel	B-Architecture
memory	I-Architecture
architecture	I-Architecture
.	O
</s>
<s>
There	O
were	O
four	O
models	O
of	O
the	O
IBM	B-Device
System/360	I-Device
Model	I-Device
91	I-Device
.	O
</s>
<s>
They	O
differed	O
by	O
their	O
main	O
memory	O
configuration	O
,	O
all	O
using	O
IBM	O
's	O
2395	B-Device
Processor	I-Device
Storage	I-Device
.	O
</s>
<s>
IBM	O
had	O
a	O
long	O
history	O
with	O
NASA	O
including	O
the	O
use	O
of	O
IBM	O
components	O
on	O
manned	O
space	O
flights	O
such	O
as	O
the	O
IBM	O
ASC-15	O
on	O
Saturn	O
1	O
,	O
the	O
IBM	O
ASC-15B	O
on	O
the	O
Titan	O
Family	O
,	O
IBM	O
GDC	O
on	O
Gemini	O
,	O
IBM	B-Device
LVDC	I-Device
on	O
Saturn	O
1B/5	O
,	O
IBM	O
System/4	O
Pi-EP	O
on	O
the	O
MOL	O
,	O
and	O
the	O
IBM	O
System/4	O
Pi-TC	O
1	O
on	O
the	O
Apollo	O
Telescope	O
Mount	O
and	O
Skylab	O
.	O
</s>
<s>
The	O
Model	O
95	O
was	O
a	O
variant	O
of	O
the	O
Model	O
91	O
with	O
1	O
megabyte	O
of	O
thin-film	B-General_Concept
memory	I-General_Concept
and	O
4	O
megabytes	O
of	O
core	O
memory	O
.	O
</s>
<s>
The	O
services	O
it	O
provided	O
included	O
job	O
submittal	O
,	O
a	O
"	O
mailbox	O
"	O
system	O
and	O
FTP	B-Protocol
.	O
</s>
