<s>
The	O
IBM	B-Device
2361	I-Device
Large	I-Device
Capacity	I-Device
Storage	I-Device
(	O
LCS	O
)	O
is	O
an	O
optional	O
component	O
of	O
the	O
IBM	B-Application
System/360	I-Application
models	O
50	B-Device
,	O
65	O
(	O
when	O
not	O
being	O
used	O
as	O
a	O
multiprocessor	B-Operating_System
)	O
,	O
and	O
75	O
computers	O
.	O
</s>
<s>
Storage	O
is	O
implemented	O
using	O
magnetic	O
cores	O
;	O
the	O
cycle	O
time	O
is	O
8	O
microseconds	O
and	O
the	O
access	B-General_Concept
time	I-General_Concept
is	O
3.6	O
microseconds	O
.	O
</s>
<s>
This	O
component	O
is	O
also	O
called	O
IBM	B-Device
2361	I-Device
Core	I-Device
Storage	I-Device
or	O
IBM	B-Device
2361	I-Device
Large	I-Device
Core	I-Device
Storage	I-Device
.	O
</s>
<s>
It	O
provides	O
additional	O
main	O
storage	O
with	O
a	O
slower	O
access	B-General_Concept
time	I-General_Concept
than	O
the	O
standard	O
storage	O
of	O
the	O
machine	O
—	O
for	O
example	O
its	O
8μsec	O
compares	O
to	O
750nsec	O
for	O
main	O
storage	O
on	O
the	O
Model	O
65	O
.	O
</s>
<s>
The	O
IBM	B-Device
2361	I-Device
was	O
also	O
provided	O
to	O
NASA	O
for	O
use	O
on	O
their	O
IBM	B-Device
7094	I-Device
real-time	O
system	O
,	O
where	O
it	O
supplied	O
524,000	O
36-bit	O
words	O
of	O
additional	O
memory	O
.	O
</s>
<s>
There	O
are	O
two	O
models	O
of	O
the	O
IBM	B-Device
2361	I-Device
:	O
model	O
1	O
has	O
1,048,576	O
bytes	O
(	O
1MB	O
)	O
and	O
model	O
2	O
has	O
2,097,152	O
bytes	O
(	O
2MB	O
)	O
.	O
</s>
<s>
The	O
IBM	B-Device
2361	I-Device
can	O
be	O
shared	O
between	O
two	O
System/360	B-Application
computers	O
.	O
</s>
<s>
When	O
one	O
of	O
the	O
sharing	O
systems	O
is	O
a	O
model	O
50	B-Device
and	O
the	O
other	O
a	O
model	O
65	O
or	O
model	O
75	O
,	O
the	O
model	O
50	B-Device
may	O
have	O
less	O
main	O
storage	O
than	O
the	O
model	O
65	O
or	O
model	O
75	O
.	O
</s>
<s>
If	O
a	O
system	O
contains	O
an	O
even	O
number	O
of	O
IBM	B-Device
2361	I-Device
components	O
and	O
at	O
least	O
one	O
model	O
65	O
or	O
model	O
75	O
processor	O
,	O
the	O
IBM	B-Device
2361s	I-Device
can	O
be	O
interleaved	B-General_Concept
to	O
improve	O
sequential	B-General_Concept
access	I-General_Concept
time	O
.	O
</s>
<s>
With	O
interleaving	O
,	O
the	O
first	O
64-bit	O
word	O
is	O
contained	O
in	O
the	O
first	O
IBM	B-Device
2361	I-Device
,	O
the	O
second	O
in	O
the	O
second	O
,	O
the	O
third	O
in	O
the	O
first	O
,	O
and	O
so	O
forth	O
.	O
</s>
<s>
When	O
doing	O
sequential	B-General_Concept
access	I-General_Concept
,	O
one	O
IBM	B-Device
2361	I-Device
can	O
complete	O
its	O
cycle	O
while	O
the	O
other	O
IBM	B-Device
2361	I-Device
is	O
starting	O
the	O
next	O
cycle	O
.	O
</s>
<s>
OS/360	B-Application
allows	O
the	O
user	O
to	O
request	O
memory	O
in	O
either	O
processor	O
storage	O
(	O
"	O
hierarchy	O
0	O
"	O
)	O
or	O
the	O
slower	O
LCS	O
(	O
"	O
hierarchy	O
1	O
"	O
)	O
.	O
</s>
<s>
The	O
OS/360	B-Application
linkage	O
editor	O
also	O
provides	O
a	O
HIARCHY	O
control	O
statement	O
to	O
assign	O
specific	O
control	O
sections	O
to	O
a	O
particular	O
hierarchy	O
,	O
thus	O
a	O
program	O
can	O
be	O
split	O
into	O
sections	O
to	O
run	O
in	O
processor	O
storage	O
and	O
sections	O
to	O
run	O
in	O
LCS	O
.	O
</s>
