<s>
Oryx/Pecos	B-Operating_System
is	O
a	O
proprietary	B-Application
operating	B-General_Concept
system	I-General_Concept
developed	O
from	O
scratch	O
by	O
Bell	O
Labs	O
beginning	O
in	O
1978	O
for	O
the	O
express	O
purpose	O
of	O
running	O
T	O
's	O
large-scale	O
PBX	B-Device
switching	O
equipment	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
was	O
first	O
used	O
with	O
T	O
's	O
flagship	O
System	O
75	O
,	O
and	O
until	O
very	O
recently	O
,	O
was	O
used	O
in	O
all	O
variations	O
up	O
through	O
and	O
including	O
Definity	O
G3	O
(	O
Generic	O
3	O
)	O
switches	O
,	O
now	O
manufactured	O
by	O
AT&	O
T/Lucent	O
Technologies	O
spinoff	O
Avaya	O
.	O
</s>
<s>
The	O
last	O
system	O
based	O
on	O
Oryx/Pecos	B-Operating_System
was	O
the	O
Avaya	O
G3	O
CSI	O
running	O
release	O
13.1	O
Definity	O
software	O
.	O
</s>
<s>
Although	O
widely	O
believed	O
to	O
be	O
a	O
Unix-like	B-Operating_System
variant	O
developed	O
directly	O
by	O
Bell	O
Labs	O
,	O
that	O
is	O
not	O
the	O
case	O
,	O
as	O
it	O
is	O
not	O
based	O
on	O
any	O
version	O
of	O
Unix	O
.	O
</s>
<s>
Oryx/Pecos	B-Operating_System
consists	O
of	O
a	O
kernel	O
(	O
Oryx	O
)	O
,	O
and	O
the	O
associated	O
processes	O
running	O
on	O
top	O
of	O
it	O
(	O
Pecos	O
)	O
.	O
</s>
<s>
Features	O
normally	O
found	O
in	O
commercial	O
operating	B-General_Concept
systems	I-General_Concept
are	O
not	O
found	O
in	O
Oryx/Pecos	B-Operating_System
.	O
</s>
<s>
There	O
is	O
one	O
historical	O
link	O
between	O
Oryx/Pecos	B-Operating_System
and	O
Unix	O
:	O
the	O
authors	O
of	O
the	O
above	O
article	O
proposed	O
as	O
a	O
future	O
development	O
the	O
implementation	O
of	O
a	O
UNIX	O
execution	O
environment	O
on	O
top	O
of	O
Oryx/Pecos	B-Operating_System
,	O
and	O
in	O
fact	O
,	O
such	O
a	O
project	O
was	O
undertaken	O
at	O
Denver	O
.	O
</s>
<s>
However	O
,	O
that	O
project	O
never	O
became	O
an	O
official	O
product	O
of	O
AT&T	O
or	O
Lucent	O
,	O
even	O
though	O
it	O
was	O
completed	O
successfully	O
and	O
introduced	O
internally	O
with	O
the	O
"	O
Eli	O
"	O
version	O
of	O
Oryx/Pecos	B-Operating_System
(	O
5th	O
release	O
,	O
or	O
"	O
E	O
"	O
release	O
)	O
.	O
</s>
<s>
Persons	O
working	O
in	O
large	O
office	O
environments	O
and	O
using	O
AT&T	O
,	O
Lucent	O
Technologies	O
,	O
or	O
Avaya-branded	O
telephones	O
are	O
likely	O
to	O
be	O
using	O
Oxyx-Pecos	O
indirectly	O
,	O
but	O
due	O
to	O
the	O
narrow	O
focus	O
and	O
proprietary	B-Application
nature	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
it	O
remains	O
obscure	O
.	O
</s>
<s>
In	O
2005	O
Avaya	O
discontinued	O
the	O
use	O
of	O
Oryx/Pecos	B-Operating_System
as	O
an	O
operating	B-General_Concept
system	I-General_Concept
in	O
itself	O
,	O
instead	O
porting	O
it	O
to	O
become	O
an	O
application	O
that	O
ran	O
on	O
Linux	B-Application
.	O
</s>
<s>
The	O
Definity	O
One	O
ran	O
on	O
Windows	B-Device
NT	I-Device
4.0	I-Device
with	O
a	O
Linux	B-Application
emulator	O
that	O
also	O
emulated	O
the	O
Oryx/Pecos	B-Operating_System
system	O
.	O
</s>
<s>
Allegedly	O
,	O
according	O
to	O
administrators	O
that	O
used	O
that	O
specific	O
system	O
,	O
it	O
was	O
a	O
failure	O
,	O
and	O
the	O
attempt	O
to	O
have	O
Windows	O
run	O
on	O
top	O
Oryx/Pecos	B-Operating_System
and	O
Linux	B-Application
was	O
a	O
problem	O
.	O
</s>
<s>
However	O
,	O
due	O
to	O
the	O
robust	O
nature	O
of	O
carrier-grade	O
equipment	O
,	O
and	O
the	O
widespread	O
use	O
of	O
AT&	O
T/Lucent/Avaya	O
PBX	B-Device
systems	O
,	O
Oryx/Pecos	B-Operating_System
will	O
most	O
probably	O
continue	O
to	O
be	O
supported	O
indefinitely	O
.	O
</s>
