<s>
NOS	B-Operating_System
(	O
Network	O
Operating	B-General_Concept
System	I-General_Concept
)	O
is	O
a	O
discontinued	O
operating	B-General_Concept
system	I-General_Concept
with	O
time-sharing	B-General_Concept
capabilities	O
,	O
written	O
by	O
Control	O
Data	O
Corporation	O
in	O
1975	O
.	O
</s>
<s>
NOS	B-Operating_System
ran	O
on	O
the	O
60-bit	B-Device
CDC	B-Device
6000	I-Device
series	I-Device
of	O
mainframe	B-Architecture
computers	I-Architecture
and	O
their	O
successors	O
.	O
</s>
<s>
NOS	B-Operating_System
replaced	O
the	O
earlier	O
CDC	B-Operating_System
Kronos	I-Operating_System
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
1970s	O
.	O
</s>
<s>
NOS	B-Operating_System
was	O
intended	O
to	O
be	O
the	O
sole	O
operating	B-General_Concept
system	I-General_Concept
for	O
all	O
CDC	O
machines	O
,	O
a	O
fact	O
CDC	O
promoted	O
heavily	O
.	O
</s>
<s>
NOS	B-Operating_System
was	O
replaced	O
with	O
NOS/VE	B-Operating_System
on	O
the	O
64-bit	B-Device
Cyber-180	B-Device
systems	O
in	O
the	O
mid-1980s	O
.	O
</s>
<s>
Version	O
1	O
of	O
NOS	B-Operating_System
continued	O
to	O
be	O
updated	O
until	O
about	O
1981	O
;	O
NOS	B-Operating_System
version	O
2	O
was	O
released	O
early	O
1982	O
.	O
</s>
<s>
From	O
NOS	B-Operating_System
Version	O
1	O
Terminal	O
User	O
's	O
Instant	O
Manual	O
,	O
CDC	O
,	O
1975-1980	O
.	O
</s>
