<s>
In	O
distributed	B-Architecture
computing	I-Architecture
,	O
an	O
object	B-General_Concept
request	I-General_Concept
broker	I-General_Concept
(	O
ORB	O
)	O
is	O
a	O
middleware	B-General_Concept
which	O
allows	O
program	O
calls	O
to	O
be	O
made	O
from	O
one	O
computer	O
to	O
another	O
via	O
a	O
computer	B-Architecture
network	I-Architecture
,	O
providing	O
location	O
transparency	O
through	O
remote	B-Operating_System
procedure	I-Operating_System
calls	I-Operating_System
.	O
</s>
<s>
ORBs	O
promote	O
interoperability	O
of	O
distributed	B-Operating_System
object	I-Operating_System
systems	I-Operating_System
,	O
enabling	O
such	O
systems	O
to	O
be	O
built	O
by	O
piecing	O
together	O
objects	O
from	O
different	O
vendors	O
,	O
while	O
different	O
parts	O
communicate	O
with	O
each	O
other	O
via	O
the	O
ORB	O
.	O
</s>
<s>
ORBs	O
handle	O
the	O
transformation	O
of	O
in-process	O
data	O
structures	O
to	O
and	O
from	O
the	O
raw	O
byte	O
sequence	O
,	O
which	O
is	O
transmitted	O
over	O
the	O
network	O
.	O
</s>
<s>
This	O
is	O
called	O
marshalling	B-Application
or	O
serialization	B-Application
.	O
</s>
<s>
In	O
addition	O
to	O
marshalling	B-Application
data	O
,	O
ORBs	O
often	O
expose	O
many	O
more	O
features	O
,	O
such	O
as	O
distributed	B-General_Concept
transactions	I-General_Concept
,	O
directory	O
services	O
or	O
real-time	O
scheduling	O
.	O
</s>
<s>
Some	O
ORBs	O
,	O
such	O
as	O
CORBA-compliant	O
systems	O
,	O
use	O
an	O
interface	B-General_Concept
description	I-General_Concept
language	I-General_Concept
to	O
describe	O
the	O
data	O
that	O
is	O
to	O
be	O
transmitted	O
on	O
remote	O
calls	O
.	O
</s>
<s>
In	O
object-oriented	B-Language
languages	I-Language
,	O
an	O
ORB	O
actually	O
provides	O
a	O
framework	B-Architecture
which	O
enables	O
remote	O
objects	O
to	O
be	O
used	O
over	O
the	O
network	O
,	O
in	O
the	O
same	O
way	O
as	O
if	O
they	O
were	O
local	O
and	O
part	O
of	O
the	O
same	O
process	B-Operating_System
.	O
</s>
<s>
After	O
the	O
stub	O
's	O
methods	O
are	O
invoked	O
,	O
client-side	O
ORB	O
performs	O
the	O
marshalling	B-Application
of	O
invocation	O
data	O
,	O
and	O
forwards	O
the	O
request	O
to	O
the	O
server-side	O
ORB	O
.	O
</s>
<s>
The	O
whole	O
process	B-Operating_System
is	O
transparent	O
,	O
resulting	O
in	O
remote	O
objects	O
appearing	O
as	O
if	O
they	O
were	O
local	O
.	O
</s>
<s>
CORBA	B-Architecture
-	O
Common	B-Architecture
Object	I-Architecture
Request	I-Architecture
Broker	I-Architecture
Architecture	I-Architecture
.	O
</s>
