<s>
The	O
IBM	B-Device
2365	I-Device
Processor	I-Device
Storage	I-Device
is	O
a	O
magnetic-core	O
memory	O
storage	O
unit	O
that	O
is	O
a	O
component	O
of	O
the	O
IBM	B-Application
System/360	I-Application
models	O
65	B-Device
,	O
67	B-Device
,	O
75	B-Device
and	O
85	B-Device
computers	O
,	O
which	O
were	O
released	O
between	O
1965	O
and	O
1968	O
.	O
</s>
<s>
Storage	O
is	O
implemented	O
using	O
magnetic	O
cores	O
with	O
a	O
storage	O
width	O
of	O
72	O
bits	O
,	O
which	O
comprise	O
64	O
data	O
bits	O
(	O
8	O
bytes	B-Application
,	O
or	O
one	O
doubleword	O
)	O
plus	O
8	O
parity	O
bits	O
.	O
</s>
<s>
The	O
IBM	B-Device
2365	I-Device
model	O
1	O
contains	O
131,072	O
(	O
128K	O
)	O
bytes	B-Application
of	O
memory	O
;	O
all	O
other	O
models	O
contain	O
262,144	O
(	O
256K	O
)	O
bytes	B-Application
.	O
</s>
<s>
Addressing	O
for	O
the	O
stacks	O
is	O
interleaved	B-General_Concept
,	O
so	O
the	O
first	O
64-bit	B-Device
word	O
is	O
in	O
one	O
stack	O
,	O
the	O
second	O
in	O
the	O
other	O
stack	O
,	O
and	O
so	O
forth	O
.	O
</s>
<s>
Model	O
1	O
is	O
used	O
on	O
the	O
System/360	B-Application
model	O
65	B-Device
when	O
not	O
used	O
as	O
a	O
multiprocessor	O
.	O
</s>
<s>
Model	O
2	O
is	O
used	O
on	O
the	O
System/360	B-Application
models	O
65	B-Device
(	O
when	O
not	O
used	O
as	O
a	O
multiprocessor	O
)	O
and	O
67-1	O
.	O
</s>
<s>
Model	O
3	O
is	O
used	O
on	O
the	O
System/360	B-Application
model	O
75	B-Device
.	O
</s>
<s>
Model	O
5	O
is	O
used	O
on	O
the	O
System/360	B-Application
model	O
85	B-Device
.	O
</s>
<s>
Model	O
13	O
is	O
used	O
on	O
the	O
System/360	B-Application
model	O
65	B-Device
when	O
used	O
as	O
a	O
multiprocessor	O
.	O
</s>
<s>
The	O
IBM	B-Device
2365	I-Device
model	O
5	O
is	O
special	O
because	O
the	O
System/360	B-Application
model	O
85	B-Device
accesses	O
memory	O
in	O
128-bit	O
(	O
16	O
byte	B-Application
)	O
units	O
,	O
unlike	O
the	O
other	O
System/360	B-Application
models	O
which	O
support	O
the	O
IBM	B-Device
2365	I-Device
,	O
all	O
of	O
which	O
access	O
64-bit	B-Device
(	O
8	O
byte	B-Application
)	O
units	O
.	O
</s>
<s>
On	O
the	O
System/360	B-Application
model	O
85	B-Device
,	O
the	O
IBM	B-Device
2365	I-Device
model	O
5	O
operates	O
with	O
a	O
cycle	O
time	O
of	O
1040	O
nanoseconds	O
,	O
and	O
two	O
or	O
four	O
of	O
them	O
are	O
required	O
.	O
</s>
<s>
Because	O
the	O
System/360	B-Application
model	O
85	B-Device
CPU	O
is	O
so	O
much	O
faster	O
than	O
memory	O
,	O
if	O
there	O
are	O
two	O
IBM	B-Device
2365	I-Device
model	O
5	O
components	O
they	O
are	O
two-way	O
interleaved	B-General_Concept
,	O
and	O
if	O
there	O
are	O
four	O
IBM	B-Device
2365	I-Device
model	O
5	O
components	O
they	O
are	O
four-way	O
interleaved	B-General_Concept
.	O
</s>
<s>
Because	O
the	O
IBM	B-Device
2365	I-Device
model	O
5	O
is	O
internally	O
two-way	O
interleaved	B-General_Concept
,	O
sequential	O
128-bit	O
memory	O
operations	O
issued	O
by	O
the	O
System/360	B-Application
model	O
85	B-Device
CPU	O
traverse	O
all	O
the	O
memory	O
components	O
before	O
cycling	O
back	O
to	O
the	O
first	O
.	O
</s>
<s>
The	O
IBM	B-Device
2365	I-Device
model	O
5	O
is	O
used	O
only	O
with	O
the	O
System/360	B-Application
model	O
85	B-Device
with	O
524,288	O
(	O
512K	O
)	O
or	O
1,048,576	O
bytes	B-Application
(	O
1MB	O
)	O
of	O
storage	O
.	O
</s>
<s>
The	O
IBM	B-Device
System/360	I-Device
Model	I-Device
85	I-Device
,	O
when	O
configured	O
with	O
2,097,152	O
(	O
2MB	O
,	O
360/85	B-Device
K85	O
)	O
or	O
4,194,304	O
(	O
4MB	O
,	O
360/85	B-Device
L85	O
)	O
bytes	B-Application
,	O
uses	O
the	O
IBM	O
2385	O
instead	O
of	O
the	O
IBM	B-Device
2365	I-Device
Processor	I-Device
Storage	I-Device
.	O
</s>
<s>
The	O
IBM	O
2385	O
has	O
a	O
cycle	O
time	O
of	O
960	O
nanoseconds	O
compared	O
to	O
1,040	O
nanoseconds	O
for	O
the	O
IBM	B-Device
2365	I-Device
model	O
5	O
.	O
</s>
