<s>
UNIX	B-Operating_System
System	I-Operating_System
III	I-Operating_System
(	O
or	O
System	O
3	O
)	O
is	O
a	O
discontinued	O
version	O
of	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
released	O
by	O
T	O
's	O
Unix	B-Application
Support	O
Group	O
(	O
USG	O
)	O
.	O
</s>
<s>
AT&T	O
announced	O
System	B-Operating_System
III	I-Operating_System
in	O
late	O
1981	O
,	O
and	O
it	O
was	O
first	O
released	O
outside	O
of	O
Bell	O
Labs	O
in	O
1982	O
.	O
</s>
<s>
UNIX	B-Operating_System
System	I-Operating_System
III	I-Operating_System
was	O
a	O
mix	O
of	O
various	O
AT&T	B-Operating_System
Unixes	I-Operating_System
:	O
Version	B-Operating_System
7	I-Operating_System
Unix	I-Operating_System
,	O
PWB/UNIX	B-Operating_System
2.0	O
,	O
CB	B-Operating_System
UNIX	I-Operating_System
3.0	O
,	O
UNIX/RT	B-Operating_System
and	O
UNIX/32V	B-Operating_System
.	O
</s>
<s>
System	B-Operating_System
III	I-Operating_System
supported	O
the	O
DEC	B-Device
PDP-11	I-Device
and	O
VAX	B-Device
computers	O
.	O
</s>
<s>
The	O
system	O
was	O
apparently	O
called	O
System	B-Operating_System
III	I-Operating_System
because	O
it	O
was	O
considered	O
the	O
outside	O
release	O
of	O
UNIX/TS	O
3.0.1	O
and	O
CB	B-Operating_System
UNIX	I-Operating_System
3	O
which	O
were	O
internally	O
supported	O
Bell	O
Labs	O
Unices	O
;	O
its	O
manual	O
refers	O
to	O
it	O
as	O
UNIX	B-Application
Release	O
3.0	O
and	O
there	O
were	O
no	O
Unix	B-Application
versions	O
called	O
System	O
I	O
or	O
System	O
II	O
.	O
</s>
<s>
There	O
was	O
no	O
official	O
release	O
of	O
UNIX/TS	O
4.0	O
(	O
which	O
would	O
have	O
been	O
System	O
IV	O
)	O
either	O
,	O
so	O
System	B-Operating_System
III	I-Operating_System
was	O
succeeded	O
by	O
System	B-Operating_System
V	I-Operating_System
,	O
based	O
on	O
UNIX/TS	O
5.0	O
.	O
</s>
<s>
System	B-Operating_System
III	I-Operating_System
introduced	O
new	O
features	O
such	O
as	O
named	B-Operating_System
pipes	I-Operating_System
,	O
the	O
uname	B-Device
system	O
call	O
and	O
command	O
,	O
and	O
the	O
run	B-Application
queue	I-Application
.	O
</s>
<s>
It	O
also	O
combined	O
various	O
improvements	O
to	O
Version	B-Operating_System
7	I-Operating_System
Unix	I-Operating_System
by	O
outside	O
organizations	O
.	O
</s>
<s>
However	O
,	O
it	O
did	O
not	O
include	O
notable	O
additions	O
made	O
in	O
BSD	B-Operating_System
such	O
as	O
the	O
C	B-Operating_System
shell	I-Operating_System
(	O
csh	O
)	O
and	O
screen	O
editing	O
.	O
</s>
<s>
Third-party	O
variants	O
of	O
System	B-Operating_System
III	I-Operating_System
include	O
(	O
early	O
versions	O
of	O
)	O
HP-UX	B-Application
,	O
IRIX	B-Operating_System
,	O
IS/3	B-Operating_System
and	O
PC/IX	B-Operating_System
,	O
PC-UX	B-Operating_System
,	O
PNX	B-Device
,	O
SINIX	B-Operating_System
,	O
Venix	B-Operating_System
and	O
Xenix	B-Application
.	O
</s>
