<s>
The	O
Programmer	O
's	O
Workbench	O
(	O
PWB/UNIX	B-Operating_System
)	O
is	O
an	O
early	O
,	O
now	O
discontinued	O
,	O
version	O
of	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
that	O
had	O
been	O
created	O
in	O
the	O
Bell	O
Labs	O
Computer	O
Science	O
Research	O
Group	O
of	O
AT&T	O
.	O
</s>
<s>
Its	O
stated	O
goal	O
was	O
to	O
provide	O
a	O
time-sharing	B-General_Concept
working	O
environment	O
for	O
large	O
groups	O
of	O
programmers	O
,	O
writing	O
software	O
for	O
larger	O
batch	B-General_Concept
processing	I-General_Concept
computers	O
.	O
</s>
<s>
Prior	O
to	O
1973	O
Unix	B-Application
development	O
at	O
AT&T	O
was	O
a	O
project	O
of	O
a	O
small	O
group	O
of	O
researchers	O
in	O
Department	O
1127	O
of	O
Bell	O
Labs	O
.	O
</s>
<s>
As	O
the	O
usefulness	O
of	O
Unix	B-Application
in	O
other	O
departments	O
of	O
Bell	O
Labs	O
was	O
evident	O
,	O
the	O
company	O
decided	O
to	O
develop	O
a	O
version	O
of	O
Unix	B-Application
tailored	O
to	O
support	O
programmers	O
in	O
production	O
work	O
,	O
not	O
just	O
research	O
.	O
</s>
<s>
The	O
Programmer	O
's	O
Workbench	O
was	O
started	O
in	O
1973	O
,	O
by	O
Evan	O
Ivie	O
and	O
Rudd	O
Canaday	O
to	O
support	O
a	O
computer	O
center	O
for	O
a	O
1000-employee	O
Bell	O
Labs	O
division	O
,	O
which	O
would	O
be	O
the	O
largest	O
Unix	B-Application
site	O
for	O
several	O
years	O
.	O
</s>
<s>
PWB/UNIX	B-Operating_System
was	O
to	O
provide	O
tools	O
for	O
teams	O
of	O
programmers	O
to	O
manage	O
their	O
source	O
code	O
and	O
collaborate	O
on	O
projects	O
with	O
other	O
team	O
members	O
.	O
</s>
<s>
It	O
also	O
introduced	O
several	O
stability	O
improvements	O
beyond	O
Research	B-Operating_System
Unix	I-Operating_System
,	O
and	O
broadened	O
usage	O
of	O
the	O
Research	O
nroff	B-Device
and	O
troff	B-Language
text	O
formatters	O
,	O
via	O
efforts	O
with	O
Bell	O
Labs	O
typing	O
pools	O
that	O
led	O
to	O
the	O
-mm	O
macros	O
.	O
</s>
<s>
While	O
PWB	O
users	O
managed	O
their	O
source	O
code	O
on	O
PDP-11	B-Device
Unix	B-Application
systems	I-Application
,	O
programs	O
were	O
often	O
written	O
to	O
run	O
on	O
other	O
legacy	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
PWB	O
included	O
software	O
for	O
submitting	O
jobs	O
to	O
IBM	B-Device
System/370	I-Device
,	O
UNIVAC	B-Device
1100	I-Device
series	I-Device
,	O
and	O
XDS	O
Sigma	B-Device
5	I-Device
computers	O
.	O
</s>
<s>
PWB/UNIX	B-Operating_System
1.0	O
,	O
released	O
July	O
1	O
,	O
1977	O
was	O
based	O
on	O
Version	B-Operating_System
6	I-Operating_System
Unix	I-Operating_System
;	O
PWB	O
2.0	O
was	O
based	O
on	O
Version	B-Operating_System
7	I-Operating_System
Unix	I-Operating_System
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
was	O
advertised	O
by	O
Bell	O
System	O
Software	O
as	O
late	O
as	O
1981	O
and	O
edition	O
1.0	O
was	O
still	O
on	O
an	O
AT&T	O
price	O
list	O
for	O
educational	O
institutions	O
in	O
1984	O
.	O
</s>
<s>
Most	O
of	O
PWB/UNIX	B-Operating_System
was	O
later	O
incorporated	O
in	O
the	O
commercial	O
UNIX	B-Operating_System
System	I-Operating_System
III	I-Operating_System
and	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
releases	O
.	O
</s>
