<s>
The	O
IBM	B-Device
System/360	I-Device
Model	I-Device
50	I-Device
is	O
a	O
member	O
of	O
the	O
IBM	B-Application
System/360	I-Application
family	O
of	O
computers	O
.	O
</s>
<s>
There	O
are	O
four	O
models	O
of	O
the	O
360/50	B-Device
.	O
</s>
<s>
The	O
system	O
can	O
also	O
attach	O
IBM	B-Device
2361	I-Device
Large	I-Device
Capacity	I-Device
Storage	I-Device
(	O
LCS	O
)	O
modules	O
which	O
provide	O
up	O
to	O
8,388,608	O
bytes	O
of	O
additional	O
storage	O
,	O
however	O
with	O
a	O
considerably	O
slower	O
memory	O
cycle	O
time	O
of	O
8	O
microseconds	O
compared	O
to	O
the	O
2	O
microseconds	O
of	O
processor	O
storage	O
.	O
</s>
<s>
The	O
system	O
has	O
a	O
CPU	O
cycle	O
time	O
of	O
500	O
nanoseconds	O
,	O
25%	O
faster	O
than	O
the	O
Model	B-Device
40	I-Device
and	O
40%	O
slower	O
than	O
the	O
Model	B-Device
65	I-Device
.	O
</s>
<s>
The	O
Model	O
50	O
implements	O
the	O
complete	O
System/360	B-Device
"	I-Device
universal	I-Device
instruction	I-Device
set	I-Device
"	I-Device
architecture	I-Device
,	O
including	O
floating-point	O
,	O
decimal	O
,	O
and	O
character	O
operations	O
as	O
standard	O
features	O
.	O
</s>
<s>
Optional	O
logic	O
,	O
microcode	O
and	O
software	O
providing	O
compatibility	O
with	O
either	O
the	O
IBM	B-Device
1410/7010	I-Device
or	O
7070/7074	B-Device
systems	O
is	O
available	O
.	O
</s>
<s>
An	O
IBM	B-Device
1052	I-Device
printer/keyboard	O
for	O
use	O
as	O
an	O
operator	O
's	O
console	O
is	O
optional	O
.	O
</s>
<s>
The	O
I/O	O
options	O
include	O
one	O
channel-to-channel	B-Device
adapter	I-Device
(	O
CTCA	O
)	O
and	O
up	O
to	O
three	O
selector	O
channels	O
.	O
</s>
<s>
A	O
multiplexer	B-Device
channel	I-Device
for	O
attachment	O
of	O
slow-speed	O
devices	O
is	O
standard	O
on	O
all	O
models	O
.	O
</s>
<s>
The	O
F50	O
has	O
64	O
subchannels	O
,	O
so	O
it	O
can	O
attach	O
up	O
to	O
64	O
slow-speed	O
devices	O
on	O
its	O
multiplexer	B-Device
channel	I-Device
.	O
</s>
<s>
It	O
was	O
possible	O
to	O
choose	O
DOS/360	O
,	O
OS/360	O
MFT	O
(	O
Multi-programming	O
with	O
a	O
Fixed	O
number	O
of	O
Tasks	O
)	O
,	O
or	O
OS/360	O
MVT	O
(	O
Multi-programming	O
with	O
a	O
Variable	O
number	O
of	O
Tasks	O
)	O
as	O
the	O
operating	B-General_Concept
system	I-General_Concept
of	O
an	O
IBM	B-Device
System/360	I-Device
Model	I-Device
50	I-Device
.	O
</s>
<s>
The	O
choice	O
of	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
System/360	B-Application
Model	O
50	O
was	O
based	O
primarily	O
on	O
the	O
amount	O
of	O
main	O
storage	O
.	O
</s>
<s>
Although	O
360/50	B-Device
systems	O
equipped	O
with	O
1	O
MB	O
or	O
more	O
could	O
and	O
did	O
run	O
MVT	O
one	O
IBMer	O
described	O
this	O
as	O
"[getting]	O
blood	O
out	O
of	O
the	O
turnip	O
"	O
,	O
and	O
noted	O
that	O
"	O
most	O
did	O
n't	O
run	O
MVT	O
"	O
.	O
</s>
<s>
Reasons	O
for	O
a	O
360/50	B-Device
site	O
to	O
run	O
MFT	O
rather	O
than	O
MVT	O
were	O
:	O
</s>
<s>
CPU	O
power	O
:	O
the	O
next	O
larger	O
System/360	B-Application
,	O
the	O
Model	B-Device
65	I-Device
,	O
has	O
triple	O
the	O
power	O
.	O
</s>
<s>
IBM	O
advertised	O
time-sharing	B-General_Concept
capability	O
by	O
featuring	O
what	O
originally	O
was	O
known	O
as	O
CALL/360	O
(	O
note	O
the	O
'	O
SLASH	O
 '	O
-	O
which	O
was	O
retained	O
in	O
the	O
name	O
of	O
its	O
successor	O
)	O
and	O
later	O
was	O
named	O
CALL/OS	O
.	O
</s>
<s>
CALL/OS	O
featured	O
its	O
own	O
versions	O
of	O
BASIC	O
as	O
well	O
as	O
FORTRAN	B-Application
IV	I-Application
and	O
PL/I	B-Language
,	O
rather	O
than	O
the	O
versions	O
implemented	O
by	O
the	O
MFT/MVT	O
compilers	O
known	O
as	O
FORTRAN	B-Application
G	O
,	O
FORTRAN	B-Application
H	O
and	O
PL/I	B-Language
F	O
.	O
CALL/OS	O
is	O
sometimes	O
referred	O
to	O
as	O
"	O
CALL-OS	O
"	O
.	O
</s>
<s>
Installations	O
with	O
a	O
larger	O
model	O
of	O
the	O
System/360	B-Application
family	O
sometimes	O
ran/retained	O
the	O
combination	O
of	O
MFT	O
and	O
CALL/OS	O
,	O
rather	O
than	O
switch	O
to	O
MVT	O
,	O
a	O
pre-requisite	O
for	O
TSO	B-Application
,	O
after	O
an	O
upgrade	O
.	O
</s>
