<s>
Columbus	O
UNIX	B-Application
,	O
or	O
CB	B-Operating_System
UNIX	I-Operating_System
,	O
is	O
a	O
discontinued	O
variant	O
of	O
the	O
UNIX	B-Application
operating	I-Application
system	I-Application
used	O
internally	O
at	O
Bell	O
Labs	O
for	O
administrative	O
databases	B-Application
and	O
transaction	O
processing	O
.	O
</s>
<s>
It	O
was	O
developed	O
at	O
the	O
Columbus	O
,	O
Ohio	O
branch	O
,	O
based	O
on	O
V6	B-Operating_System
,	O
V7	B-Operating_System
and	O
PWB	B-Operating_System
Unix	B-Application
.	O
</s>
<s>
CB	B-Operating_System
UNIX	I-Operating_System
was	O
developed	O
to	O
address	O
deficiencies	O
inherent	O
in	O
Research	B-Operating_System
Unix	I-Operating_System
,	O
notably	O
the	O
lack	O
of	O
interprocess	B-Operating_System
communication	I-Operating_System
(	O
IPC	O
)	O
and	O
file	B-Application
locking	I-Application
,	O
considered	O
essential	O
for	O
a	O
database	B-Application
management	I-Application
system	I-Application
.	O
</s>
<s>
Several	O
Bell	O
System	O
operation	O
support	O
system	O
products	O
were	O
based	O
on	O
CB	B-Operating_System
UNIX	I-Operating_System
such	O
as	O
Switching	O
Control	O
Center	O
System	O
.	O
</s>
<s>
The	O
primary	O
innovations	O
were	O
power-fail	O
restart	O
,	O
line	B-Operating_System
disciplines	I-Operating_System
,	O
terminal	O
types	O
,	O
and	O
IPC	O
features	O
.	O
</s>
<s>
The	O
interprocess	B-Operating_System
communication	I-Operating_System
features	O
developed	O
for	O
CB	B-Operating_System
UNIX	I-Operating_System
were	O
message	O
queues	O
,	O
semaphores	B-Operating_System
and	O
shared	B-Operating_System
memory	I-Operating_System
support	O
.	O
</s>
<s>
These	O
eventually	O
appeared	O
in	O
mainstream	O
Unix	B-Application
systems	I-Application
starting	O
with	O
System	B-Operating_System
V	I-Operating_System
in	O
1983	O
,	O
and	O
are	O
now	O
collectively	O
known	O
as	O
System	B-Operating_System
V	I-Operating_System
IPC	O
.	O
</s>
