<s>
VS/9	O
is	O
a	O
computer	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
for	O
the	O
UNIVAC	B-Device
Series	I-Device
90	I-Device
mainframes	B-Architecture
(	O
90/60	O
,	O
90/70	O
,	O
and	O
90/80	O
)	O
,	O
used	O
during	O
the	O
late	O
1960s	O
through	O
1980s	O
.	O
</s>
<s>
After	O
the	O
RCA	O
acquisition	O
by	O
Sperry	O
,	O
it	O
was	O
determined	O
that	O
the	O
RCA	O
TSOS	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
was	O
far	O
more	O
advanced	O
than	O
the	O
Univac	O
counterpart	O
,	O
so	O
the	O
company	O
opted	O
to	O
merge	O
the	O
Univac	O
hardware	O
with	O
the	O
RCA	O
software	O
and	O
introduced	O
the	O
90/70	O
.	O
</s>
<s>
In	O
September	O
1971	O
,	O
RCA	O
decided	O
to	O
exit	O
the	O
mainframe	B-Architecture
computer	I-Architecture
business	O
after	O
losing	O
about	O
half	O
a	O
billion	O
dollars	O
trying	O
(	O
and	O
failing	O
)	O
to	O
compete	O
against	O
IBM	O
.	O
</s>
<s>
This	O
included	O
RCA	O
's	O
Spectra	B-Device
series	O
of	O
computers	O
,	O
various	O
external	O
hardware	O
designs	O
(	O
such	O
as	O
video	O
terminals	O
,	O
tape	O
drives	O
and	O
punched	B-Architecture
card	I-Architecture
readers	O
)	O
,	O
and	O
its	O
operating	B-General_Concept
system	I-General_Concept
,	O
Time	B-Operating_System
Sharing	I-Operating_System
Operating	I-Operating_System
System	I-Operating_System
(	O
TSOS	B-Operating_System
)	O
.	O
</s>
<s>
TSOS	B-Operating_System
may	O
have	O
been	O
a	O
better	O
operating	B-General_Concept
system	I-General_Concept
from	O
a	O
user	O
standpoint	O
than	O
any	O
of	O
IBM	O
's	O
,	O
but	O
at	O
the	O
time	O
,	O
operating	B-General_Concept
systems	I-General_Concept
were	O
not	O
considered	O
something	O
sold	O
separately	O
from	O
the	O
computer	O
,	O
the	O
manufacturer	O
included	O
it	O
free	O
as	O
part	O
of	O
the	O
purchase	O
price	O
.	O
</s>
<s>
Univac	O
introduced	O
some	O
additional	O
new	O
features	O
to	O
TSOS	B-Operating_System
,	O
and	O
renamed	O
it	O
VS/9	O
.	O
</s>
<s>
The	O
name	O
'	O
TSOS	B-Operating_System
 '	O
however	O
,	O
remained	O
as	O
the	O
username	O
of	O
the	O
primary	O
privileged	O
(	O
System	O
Manager	O
)	O
account	O
,	O
which	O
on	O
Unix-type	O
systems	O
,	O
is	O
called	O
'	O
root	O
 '	O
.	O
</s>
<s>
RCA	O
also	O
sold	O
TSOS	B-Operating_System
to	O
what	O
would	O
become	O
Fujitsu	O
,	O
and	O
it	O
is	O
the	O
basis	O
for	O
Fujitsu	O
's	O
BS2000	B-Application
operating	B-General_Concept
system	I-General_Concept
on	O
its	O
mainframes	B-Architecture
of	O
the	O
same	O
name	O
.	O
</s>
<s>
The	O
VDT	O
also	O
supported	O
direct	O
cursor	B-Application
positioning	O
and	O
input	O
protection	O
through	O
a	O
cursor	B-Application
which	O
indicated	O
that	O
only	O
text	O
after	O
the	O
cursor	B-Application
was	O
to	O
be	O
recognized	O
.	O
</s>
<s>
Where	O
interactive	O
terminals	O
were	O
controlled	O
directly	O
by	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
transactional	O
terminals	O
were	O
controlled	O
from	O
a	O
batch	O
program	O
.	O
</s>
<s>
Initially	O
,	O
this	O
batch	O
program	O
,	O
known	O
as	O
MCP	O
for	O
Multichannel	O
Communications	O
Program	O
,	O
was	O
developed	O
for	O
the	O
RCA	O
and	O
Sperry	O
batch-oriented	O
operating	B-General_Concept
systems	I-General_Concept
,	O
TDOS	O
(	O
Tape-Disk	O
Operating	B-General_Concept
System	I-General_Concept
)	O
and	O
DOS	O
(	O
Disk	O
Operating	B-General_Concept
System	I-General_Concept
)	O
.	O
</s>
<s>
Once	O
it	O
became	O
clear	O
that	O
they	O
would	O
be	O
phased	O
out	O
in	O
favor	O
of	O
the	O
much	O
more	O
robust	O
interactive	O
operating	B-General_Concept
system	I-General_Concept
,	O
VMOS	O
,	O
MCP	O
was	O
ported	O
to	O
run	O
on	O
VMOS	O
.	O
</s>
<s>
VMOS	O
(	O
Virtual	B-Operating_System
Memory	I-Operating_System
Operating	I-Operating_System
System	I-Operating_System
)	O
became	O
the	O
new	O
moniker	O
for	O
TSOS	B-Operating_System
on	O
RCA	B-Device
Spectra	I-Device
70	I-Device
models	O
46	O
,	O
61	O
,	O
3	O
,	O
and	O
7	O
computers	O
,	O
and	O
then	O
initially	O
on	O
Univac	O
Series	O
70	O
(	O
formerly	O
RCA	O
)	O
computers	O
.	O
</s>
<s>
Eventually	O
,	O
MCP	O
was	O
enhanced	O
to	O
support	O
Sperry	O
Univac	O
terminals	O
and	O
its	O
name	O
was	O
changed	O
to	O
COS	O
(	O
Communication	O
Operating	B-General_Concept
System	I-General_Concept
)	O
.	O
</s>
<s>
If	O
a	O
port	O
was	O
designated	O
an	O
interactive	O
port	O
,	O
it	O
was	O
controlled	O
by	O
the	O
timesharing	O
services	O
integrated	O
into	O
the	O
VMOS	O
or	O
VS/9	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
What	O
made	O
much	O
of	O
this	O
possible	O
was	O
the	O
operating	B-General_Concept
system	I-General_Concept
's	O
ability	O
to	O
manage	O
"	O
virtual	O
memory	O
"	O
,	O
or	O
temporarily	O
save	O
pages	O
of	O
memory	O
(	O
including	O
executing	O
programs	O
)	O
to	O
disk	O
or	O
drum	O
while	O
not	O
in	O
use	O
and	O
then	O
retrieve	O
them	O
later	O
as	O
needed	O
.	O
</s>
<s>
That	O
is	O
,	O
all	O
the	O
network	O
protocol	O
intelligence	O
,	O
including	O
terminal	O
polling	O
,	O
error	O
recovery	O
,	O
and	O
message	O
construction	O
resided	O
in	O
the	O
mainframe	B-Architecture
,	O
while	O
the	O
CCM	O
and	O
MCC	O
simply	O
acted	O
as	O
conduits	O
between	O
the	O
mainframe	B-Architecture
and	O
the	O
phone	O
lines	O
.	O
</s>
<s>
It	O
was	O
not	O
until	O
the	O
MCC	O
was	O
used	O
as	O
a	O
true	O
front	O
end	O
processor	O
that	O
much	O
of	O
this	O
overhead	O
(	O
such	O
as	O
polling	O
and	O
error	O
recovery	O
)	O
was	O
offloaded	O
from	O
the	O
mainframe	B-Architecture
,	O
thus	O
freeing	O
up	O
computer	O
time	O
for	O
running	O
application	O
programs	O
.	O
</s>
<s>
VS/9	O
supported	O
one	O
or	O
more	O
card	O
readers	O
,	O
which	O
were	O
connected	O
to	O
the	O
computer	O
and	O
activated	O
by	O
the	O
user	O
placing	O
a	O
card	B-Architecture
deck	I-Architecture
in	O
the	O
hopper	O
and	O
pressing	O
the	O
"	O
Start	O
"	O
button	O
.	O
</s>
<s>
If	O
the	O
card	B-Architecture
deck	I-Architecture
consisted	O
of	O
a	O
valid	O
login	O
,	O
it	O
would	O
process	O
the	O
card	B-Architecture
deck	I-Architecture
as	O
a	O
job	O
to	O
execute	O
.	O
</s>
<s>
Unsolicited	O
messages	O
originating	O
in	O
the	O
operating	B-General_Concept
system	I-General_Concept
were	O
also	O
logged	O
to	O
the	O
system	O
console	O
printer	O
.	O
</s>
<s>
Supply	O
input	O
data	O
via	O
punched	B-Architecture
cards	I-Architecture
or	O
magnetic	O
tapes	O
.	O
</s>
<s>
This	O
was	O
necessary	O
for	O
disks	O
that	O
housed	O
the	O
operating	B-General_Concept
system	I-General_Concept
and	O
the	O
files	O
that	O
supported	O
the	O
transactional	O
terminals	O
.	O
</s>
<s>
RBP	O
allowed	O
remote	O
users	O
to	O
submit	O
batch	O
jobs	O
for	O
execution	O
on	O
the	O
mainframe	B-Architecture
and	O
receive	O
the	O
results	O
back	O
at	O
their	O
offsite	O
printer	O
.	O
</s>
<s>
Typically	O
,	O
a	O
remote	O
batch	O
device	O
consisted	O
of	O
a	O
card	O
reader	O
and	O
a	O
printer	O
connected	O
to	O
a	O
communication	O
line	O
which	O
interfaced	O
with	O
the	O
remote	O
batch	O
services	O
in	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
account	O
name	O
was	O
the	O
equivalent	O
of	O
a	O
directory	O
name	O
under	O
Unix-style	O
user	O
accounts	O
,	O
with	O
the	O
note	O
that	O
the	O
user	O
name	O
indicated	O
which	O
person	O
sharing	O
that	O
account	O
was	O
the	O
party	O
using	O
it	O
.	O
</s>
<s>
Unlike	O
other	O
systems	O
where	O
an	O
interactive	O
debugger	O
required	O
either	O
you	O
run	O
a	O
program	O
to	O
use	O
it	O
or	O
link	O
a	O
module	O
into	O
a	O
program	O
,	O
IDA	O
was	O
a	O
part	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
and	O
its	O
commands	O
were	O
available	O
from	O
break	O
mode	O
.	O
</s>
<s>
Another	O
very	O
helpful	O
,	O
but	O
unsupported	O
product	O
for	O
debugging	O
operating	B-General_Concept
system	I-General_Concept
problems	O
was	O
a	O
program	O
called	O
"	O
CareCity	O
"	O
.	O
</s>
<s>
The	O
VS/9	O
operating	B-General_Concept
system	I-General_Concept
was	O
supplied	O
as	O
pre-assembled	O
modules	O
on	O
magnetic	O
tapes	O
.	O
</s>
<s>
During	O
installation	O
,	O
selected	O
modules	O
were	O
linked	O
together	O
based	O
on	O
the	O
configuration	O
parameters	O
supplied	O
to	O
form	O
the	O
functioning	O
operating	B-General_Concept
system	I-General_Concept
and	O
then	O
saved	O
to	O
disk	O
.	O
</s>
<s>
CareCity	O
enabled	O
the	O
administrator	O
to	O
view	O
the	O
operating	B-General_Concept
system	I-General_Concept
memory	O
contents	O
using	O
addresses	O
relative	O
to	O
the	O
start	O
of	O
each	O
operating	B-General_Concept
system	I-General_Concept
module	O
.	O
</s>
<s>
This	O
could	O
all	O
be	O
done	O
while	O
the	O
operating	B-General_Concept
system	I-General_Concept
was	O
in	O
use	O
.	O
</s>
<s>
Public	O
files	O
in	O
the	O
special	O
account	O
TSOS	B-Operating_System
could	O
be	O
accessed	O
by	O
using	O
alone	O
as	O
the	O
first	O
character	O
of	O
the	O
file	O
,	O
unless	O
the	O
file	O
began	O
with	O
a	O
name	O
that	O
was	O
identical	O
to	O
an	O
account	O
number	O
,	O
in	O
which	O
case	O
the	O
explicit	O
account	O
reference	O
.	O
</s>
<s>
was	O
what	O
would	O
be	O
called	O
the	O
path	B-Application
name	I-Application
for	O
missing	O
files	O
referenced	O
by	O
name	O
which	O
were	O
not	O
found	O
in	O
the	O
user	O
's	O
account	O
.	O
</s>
<s>
TSOS	B-Operating_System
was	O
also	O
the	O
"	O
default	O
"	O
account	O
for	O
a	O
file	O
that	O
was	O
referenced	O
that	O
did	O
not	O
exist	O
locally	O
.	O
</s>
<s>
For	O
example	O
,	O
to	O
execute	O
the	O
EDT	B-Application
editor	I-Application
program	O
,	O
one	O
would	O
issue	O
the	O
command	O
to	O
run	O
a	O
program	O
,	O
EXEC	O
,	O
followed	O
by	O
the	O
name	O
of	O
the	O
file	O
,	O
which	O
was	O
called	O
EDT	B-Application
.	O
</s>
<s>
When	O
Unisys	O
discontinued	O
sales	O
of	O
the	O
9000	O
series	O
mainframes	B-Architecture
in	O
favor	O
of	O
the	O
EXEC	O
8	O
series	O
computers	O
(	O
probably	O
because	O
they	O
were	O
no	O
longer	O
cost	O
effective	O
,	O
and	O
the	O
market	O
for	O
mainframes	B-Architecture
had	O
shrank	O
)	O
,	O
VS/9	O
was	O
effectively	O
abandoned	O
by	O
the	O
company	O
.	O
</s>
