<s>
OPS5	B-Language
is	O
a	O
rule-based	O
or	O
production	B-Application
system	I-Application
computer	B-Language
language	I-Language
,	O
notable	O
as	O
the	O
first	O
such	O
language	O
to	O
be	O
used	O
in	O
a	O
successful	O
expert	B-Application
system	I-Application
,	O
the	O
R1/XCON	B-Application
system	O
used	O
to	O
configure	O
VAX	B-Device
computers	O
.	O
</s>
<s>
The	O
OPS	O
(	O
said	O
to	O
be	O
short	O
for	O
"	O
Official	O
Production	B-Application
System	I-Application
"	O
)	O
family	O
was	O
developed	O
in	O
the	O
late	O
1970s	O
by	O
Charles	O
Forgy	O
while	O
at	O
Carnegie	O
Mellon	O
University	O
.	O
</s>
<s>
Allen	O
Newell	O
's	O
research	O
group	O
in	O
artificial	B-Application
intelligence	I-Application
had	O
been	O
working	O
on	O
production	B-Application
systems	I-Application
for	O
some	O
time	O
,	O
but	O
Forgy	O
's	O
implementation	O
,	O
based	O
on	O
his	O
Rete	B-Algorithm
algorithm	I-Algorithm
,	O
was	O
especially	O
efficient	O
,	O
sufficiently	O
so	O
that	O
it	O
was	O
possible	O
to	O
scale	O
up	O
to	O
larger	O
problems	O
involving	O
hundreds	O
or	O
thousands	O
of	O
rules	O
.	O
</s>
<s>
OPS5	B-Language
uses	O
a	O
forward	O
chaining	O
inference	O
engine	O
;	O
programs	O
execute	O
by	O
scanning	O
"	O
working	O
memory	O
elements	O
"	O
(	O
which	O
are	O
vaguely	O
object-like	O
,	O
with	O
classes	O
and	O
attributes	O
)	O
looking	O
for	O
matches	O
with	O
the	O
rules	O
in	O
"	O
production	O
memory	O
"	O
.	O
</s>
<s>
In	O
this	O
sense	O
,	O
OPS5	B-Language
is	O
an	O
execution	O
engine	O
for	O
a	O
Petri	B-Operating_System
net	I-Operating_System
extended	O
with	O
inhibitor	O
arcs	O
.	O
</s>
<s>
The	O
OPS5	B-Language
forward	O
chaining	O
process	O
makes	O
it	O
extremely	O
parallelizeable	O
during	O
the	O
matching	O
phase	O
,	O
and	O
several	O
automatic	O
parallelizing	O
compilers	O
were	O
created	O
.	O
</s>
<s>
The	O
first	O
implementation	O
of	O
OPS5	B-Language
was	O
written	O
in	O
Lisp	B-Language
,	O
and	O
later	O
rewritten	O
in	O
BLISS	B-Language
for	O
speed	O
.	O
</s>
<s>
DEC	O
OPS5	B-Language
is	O
an	O
extended	O
implementation	O
of	O
the	O
OPS5	B-Language
language	O
definition	O
,	O
developed	O
for	O
use	O
with	O
the	O
OpenVMS	B-Operating_System
,	O
RISC	O
ULTRIX	O
,	O
and	O
DEC	O
OSF/1	O
operating	O
systems	O
.	O
</s>
