<s>
The	O
Loop	B-Application
Maintenance	I-Application
Operations	I-Application
System	I-Application
(	O
LMOS	B-Application
)	O
is	O
a	O
telephone	O
company	O
trouble	B-Application
ticketing	I-Application
system	O
to	O
coordinate	O
repairs	O
of	O
local	B-Architecture
loops	I-Architecture
(	O
telephone	O
lines	O
)	O
.	O
</s>
<s>
When	O
a	O
problem	O
is	O
reported	O
by	O
a	O
subscriber	O
dialing	O
the	O
designated	O
number	O
(	O
often	O
(	O
1	O
)	O
+611	O
)	O
,	O
it	O
is	O
filed	O
and	O
relayed	O
through	O
the	O
Cross	O
Front	O
End	O
,	O
which	O
is	O
a	O
link	O
from	O
the	O
CRSAB	O
(	O
Centralized	O
Repair	O
Service	O
Answering	O
Bureau	O
)	O
to	O
the	O
LMOS	B-Application
network	O
.	O
</s>
<s>
The	O
trouble	O
report	O
is	O
then	O
sent	O
to	O
the	O
Front	O
End	O
via	O
the	O
Datakit	B-General_Concept
network	O
,	O
where	O
a	O
Basic	O
Output	O
Report	O
is	O
requested	O
(	O
usually	O
by	O
a	O
lineman	O
)	O
.	O
</s>
<s>
As	O
LMOS	B-Application
is	O
responsible	O
for	O
trouble	O
reports	O
,	O
analysis	O
,	O
and	O
similar	O
related	O
functions	O
,	O
MLT	O
does	O
the	O
actual	O
testing	O
of	O
customer	O
loops	O
.	O
</s>
<s>
Test	O
trunks	O
connect	O
MLT	O
hardware	O
to	O
the	O
telephone	O
exchanges	O
or	O
wire	O
centers	O
,	O
which	O
in	O
turn	O
connect	O
with	O
the	O
subscriber	B-Architecture
loops	I-Architecture
.	O
</s>
<s>
The	O
LMOS	B-Application
database	O
is	O
a	O
proprietary	O
file	O
system	O
,	O
designed	O
with	O
11	O
access	O
methods	O
(	O
variable	O
index	O
,	O
index	O
,	O
hash	O
tree	O
,	O
fixed	O
partition	O
file	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
This	O
is	O
highly	O
tuned	O
for	O
the	O
various	O
pieces	O
of	O
data	O
used	O
by	O
LMOS	B-Application
.	O
</s>
<s>
LMOS	B-Application
,	O
which	O
was	O
first	O
brought	O
on	O
line	O
as	O
a	O
mainframe	O
application	O
in	O
the	O
1970s	O
,	O
was	O
one	O
of	O
the	O
first	O
telephone	O
company	O
operations	O
support	O
systems	O
to	O
be	O
ported	O
to	O
the	O
UNIX	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
The	O
first	O
port	O
of	O
LMOS	B-Application
was	O
to	O
Digital	O
Equipment	O
Corporation	O
's	O
PDP	O
11/70	O
machines	O
and	O
was	O
completed	O
in	O
1981	O
.	O
</s>
<s>
Today	O
,	O
LMOS	B-Application
runs	O
on	O
HP-UX	B-Application
11i	O
systems	O
.	O
</s>
