<s>
Operating	O
System/Virtual	O
Storage	O
1	O
,	O
or	O
OS/VS1	B-Application
,	O
is	O
a	O
discontinued	O
IBM	B-Device
mainframe	I-Device
computer	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
designed	O
to	O
be	O
run	O
on	O
IBM	B-Device
System/370	I-Device
hardware	O
.	O
</s>
<s>
It	O
was	O
the	O
successor	O
to	O
the	O
Multiprogramming	O
with	O
a	O
Fixed	O
number	O
of	O
Tasks	O
(	O
MFT	O
)	O
option	O
of	O
System/360	B-Application
'	O
s	O
operating	B-General_Concept
system	I-General_Concept
OS/360	B-Application
.	O
</s>
<s>
OS/VS1	B-Application
,	O
in	O
comparison	O
to	O
its	O
predecessor	O
,	O
supported	O
virtual	B-Architecture
memory	I-Architecture
(	O
then	O
called	O
virtual	B-Architecture
storage	I-Architecture
)	O
.	O
</s>
<s>
OS/VS1	B-Application
was	O
generally	O
available	O
during	O
the	O
1970s	O
and	O
1980s	O
,	O
and	O
it	O
is	O
no	O
longer	O
supported	O
by	O
IBM	O
.	O
</s>
<s>
OS/VS1	B-Application
was	O
OS/360	B-Application
MFT	O
II	O
with	O
a	O
single	O
virtual	O
address	O
space	O
;	O
by	O
comparison	O
,	O
OS/VS2	B-Application
SVS	I-Application
was	O
OS/360	B-Application
MVT	O
with	O
a	O
single	O
virtual	O
address	O
space	O
.	O
</s>
<s>
OS/VS1	B-Application
was	O
often	O
installed	O
on	O
mid-range	O
IBM	B-Device
mainframe	I-Device
systems	O
,	O
such	O
as	O
the	O
System/370	B-Device
Model	O
145	O
and	O
,	O
later	O
,	O
the	O
System/370	B-Device
Model	O
148	O
.	O
</s>
<s>
OS/VS1	B-Application
was	O
intended	O
to	O
manage	O
a	O
medium-sized	O
work	O
load	O
(	O
for	O
the	O
1970s	O
)	O
consisting	O
only	O
of	O
batch	B-General_Concept
processing	I-General_Concept
applications	O
,	O
running	O
within	O
a	O
fixed	O
number	O
of	O
operating	B-General_Concept
system	I-General_Concept
partitions	O
via	O
the	O
batch	B-General_Concept
job	I-General_Concept
management	O
system	O
Job	B-Application
Entry	I-Application
Subsystem	I-Application
1	I-Application
(	O
JES1	B-Application
)	O
.	O
</s>
<s>
This	O
was	O
in	O
contrast	O
to	O
OS/VS2	B-Application
which	O
was	O
intended	O
to	O
handle	O
larger	O
work	O
loads	O
consisting	O
of	O
batch	O
applications	O
,	O
online	O
interactive	O
users	O
(	O
using	O
the	O
Time	B-Application
Sharing	I-Application
Option	I-Application
,	O
or	O
TSO	O
)	O
,	O
or	O
a	O
combination	O
of	O
both	O
.	O
</s>
<s>
However	O
,	O
OS/VS1	B-Application
could	O
,	O
and	O
often	O
did	O
,	O
support	O
interactive	O
applications	O
and	O
users	O
by	O
running	O
IBM	O
's	O
CICS	B-Application
transaction	O
processing	O
monitor	O
as	O
a	O
job	O
within	O
one	O
of	O
its	O
partitions	O
.	O
</s>
<s>
Installation	O
and	O
modification	O
of	O
OS/VS1	B-Application
was	O
accomplished	O
via	O
IBM	O
's	O
cumbersome	O
System	B-Application
Generation	I-Application
(	O
SYSGEN	O
)	O
process	O
.	O
</s>
<s>
OS/VS1	B-Application
included	O
a	O
replacement	O
for	O
OS/360	B-Application
RJE	O
.	O
</s>
<s>
It	O
allowed	O
submission	O
and	O
retrieval	O
of	O
jobs	O
by	O
2770	O
,	O
2780	O
and	O
3780	O
terminals	O
and	O
by	O
workstation	O
programs	O
included	O
with	O
OS/VS1	B-Application
for	O
,	O
e.g.	O
,	O
1130	O
.	O
</s>
<s>
OS/VS1	B-Application
went	O
through	O
seven	O
product	O
releases	O
.	O
</s>
<s>
IBM	O
enhanced	O
OS/VS1	B-Application
Release	O
7	O
with	O
four	O
releases	O
of	O
the	O
IBM	O
OS/VS1	B-Application
Basic	O
Programming	O
Extensions	O
(	O
BPE	O
)	O
,	O
product	O
5662-257	O
.	O
</s>
<s>
BPE	O
provides	O
support	O
for	O
new	O
1980s	O
hardware	O
,	O
such	O
as	O
3380	O
Direct	B-Application
Access	I-Application
Storage	I-Application
,	O
and	O
for	O
VM	B-Application
handshaking	O
between	O
VTAM	B-Application
and	O
VM/VTAM	O
Communications	O
Network	O
Application	O
(	O
VCNA	O
)	O
.	O
</s>
<s>
IBM	O
announced	O
the	O
last	O
BPE	O
release	O
,	O
OS/VS1	B-Application
Basic	O
Programming	O
Extensions	O
Release	O
4	O
,	O
on	O
September	O
15	O
,	O
1983	O
,	O
with	O
planned	O
general	O
availability	O
in	O
March	O
1984	O
.	O
</s>
<s>
IBM	O
announced	O
the	O
end	O
of	O
functional	O
enhancements	O
to	O
OS/VS1	B-Application
in	O
1984	O
.	O
</s>
<s>
IBM	O
recommended	O
OS/VS1	B-Application
installations	O
migrate	O
to	O
MVS/370	O
or	O
MVS/XA	O
.	O
</s>
<s>
To	O
assist	O
with	O
the	O
migration	O
to	O
MVS/XA	O
,	O
IBM	O
made	O
the	O
VM/XA	B-Application
Migration	O
Aid	O
.	O
</s>
<s>
It	O
allowed	O
installations	O
to	O
run	O
OS/VS1	B-Application
and	O
MVS/XA	O
simultaneously	O
on	O
the	O
same	O
machine	O
,	O
as	O
guests	O
of	O
a	O
third	O
systemVM/XA	O
.	O
</s>
<s>
This	O
way	O
,	O
the	O
new	O
MVS/XA	O
system	O
could	O
be	O
tested	O
while	O
the	O
old	O
production	O
OS/VS1	B-Application
system	O
was	O
still	O
in	O
use	O
.	O
</s>
<s>
On	O
January	O
24	O
,	O
1989	O
,	O
IBM	O
announced	O
the	O
intention	O
to	O
withdraw	O
OS/VS1	B-Application
and	O
OS/VS1	B-Application
BPE	O
from	O
marketing	O
effective	O
April	O
24	O
,	O
1989	O
,	O
and	O
to	O
discontinue	O
service	O
effective	O
February	O
28	O
,	O
1990	O
.	O
</s>
<s>
Although	O
IBM	O
's	O
Time	B-Application
Sharing	I-Application
Option	I-Application
(	O
TSO	O
)	O
required	O
VS2	O
,	O
customers	O
with	O
a	O
370/145	O
or	O
370/148	O
had	O
other	O
time-sharing	O
options	O
.	O
</s>
<s>
One	O
combination	O
was	O
VM/CMS	B-Application
for	O
time	O
sharing	O
,	O
and	O
a	O
guest	O
"	O
machine	O
"	O
running	O
OS/360	B-Application
MFT	O
II	O
for	O
batch	O
.	O
</s>
<s>
Optional	O
component	O
of	O
OS/360	B-Application
MFT	O
II	O
,	O
OS/360	B-Application
MVT	O
and	O
OS/VS1	B-Application
,	O
CRJE	O
allowed	O
the	O
user	O
at	O
a	O
line-mode	O
terminal	O
to	O
edit	O
text	O
datasets	O
,	O
submit	O
jobs	O
and	O
access	O
job	O
output	O
.	O
</s>
