<s>
The	O
IBM	B-Device
System/360	I-Device
Model	I-Device
85	I-Device
is	O
a	O
high-end	O
member	O
of	O
the	O
System/360	B-Application
family	O
of	O
computers	O
,	O
with	O
many	O
advanced	O
features	O
,	O
and	O
was	O
announced	O
in	O
January	O
1968	O
and	O
first	O
shipped	O
in	O
December	O
1969	O
.	O
</s>
<s>
IBM	O
built	O
only	O
about	O
30	O
360/85	B-Device
systems	O
because	O
of	O
"	O
a	O
recession	O
in	O
progress	O
"	O
.	O
</s>
<s>
The	O
four	O
models	O
of	O
the	O
360/85	B-Device
are	O
:	O
I85	O
(	O
512K	O
)	O
,	O
J85	O
(	O
1M	O
)	O
,	O
K85	O
(	O
2M	O
)	O
and	O
L85	O
(	O
4M	O
)	O
,	O
configured	O
with	O
two	O
IBM	B-Device
2365	I-Device
Processor	I-Device
Storage	I-Device
units	O
,	O
four	O
2365	B-Device
units	O
,	O
an	O
IBM	O
2385	O
Processor	O
Storage	O
unit	O
Model	O
1	O
(=	O
2M	O
)	O
,	O
or	O
an	O
IBM	O
2385	O
Processor	O
Storage	O
unit	O
Model	O
2	O
(=	O
4M	O
)	O
respectively	O
.	O
</s>
<s>
The	O
I85	O
includes	O
two-way	O
interleaved	B-General_Concept
memory	I-General_Concept
while	O
the	O
others	O
provide	O
four-way	O
interleaving	O
of	O
memory	O
access	O
.	O
</s>
<s>
The	O
System/360	B-Application
Model	O
85	O
is	O
the	O
first	O
commercially	O
available	O
computer	O
with	O
cache	O
memory	O
.	O
</s>
<s>
The	O
Model	O
85	O
has	O
both	O
Read-only	O
and	O
Writeable	O
Control	O
Storage	O
(	O
it	O
is	O
the	O
second	O
System/360	B-Application
to	O
have	O
writeable	O
control	O
storage	O
;	O
the	O
IBM	B-Device
System/360	I-Device
Model	I-Device
25	I-Device
is	O
the	O
first	O
to	O
have	O
rewriteable	O
control	O
storage	O
;	O
the	O
360/85	B-Device
was	O
introduced	O
Jan	O
.	O
30	O
,	O
1968	O
)	O
.	O
</s>
<s>
The	O
360/85	B-Device
,	O
when	O
equipped	O
with	O
the	O
709/7090/7094	O
Compatibility	O
Feature	O
,	O
</s>
<s>
with	O
the	O
use	O
of	O
an	O
emulator	B-Application
program	O
permits	O
running	O
709	B-Device
,	O
7040	B-Device
,	O
7044	B-Device
,	O
7094	B-Device
and	I-Device
7094	I-Device
II	I-Device
programs	O
.	O
</s>
<s>
In	O
some	O
respects	O
,	O
the	O
System/360	B-Application
Model	O
85	O
provided	O
a	O
glimpse	O
into	O
the	O
future	O
System/370	B-Device
product	O
line	O
(	O
particularly	O
the	O
370	O
Model	O
165	O
)	O
-	O
which	O
IBM	O
announced	O
two	O
years	O
later	O
(	O
1970	O
)	O
.	O
</s>
<s>
It	O
used	O
the	O
MST	O
circuitry	O
that	O
was	O
later	O
used	O
in	O
the	O
initial	O
System/370	B-Device
models	O
,	O
and	O
introduced	O
features	O
such	O
as	O
128-bit	O
floating	O
point	O
arithmetic	O
and	O
block	O
multiplexor	O
channels	O
that	O
are	O
also	O
part	O
of	O
the	O
System/370	B-Device
architecture	O
.	O
</s>
<s>
The	O
360/85	B-Device
uses	O
microcode	B-Device
to	O
control	O
instruction	O
execution	O
,	O
unlike	O
the	O
completely-hardwired	O
360/75	B-Device
and	O
360/91	B-Device
;	O
the	O
high-end	O
models	O
of	O
System/370	B-Device
also	O
use	O
horizontal	O
microcode	B-Device
,	O
except	O
the	O
IBM	B-Device
System/370	I-Device
model	O
195	O
.	O
</s>
