<s>
In	O
computing	O
,	O
Dynamic	B-Operating_System
Data	I-Operating_System
Exchange	I-Operating_System
(	O
DDE	O
)	O
is	O
a	O
technology	O
for	O
interprocess	B-Operating_System
communication	I-Operating_System
used	O
in	O
early	O
versions	O
of	O
Microsoft	B-Application
Windows	I-Application
and	O
OS/2	B-Application
.	O
</s>
<s>
DDE	O
was	O
partially	O
superseded	O
by	O
Object	B-Operating_System
Linking	I-Operating_System
and	I-Operating_System
Embedding	I-Operating_System
(	O
OLE	O
)	O
,	O
and	O
is	O
currently	O
maintained	O
in	O
Windows	O
systems	O
only	O
for	O
the	O
sake	O
of	O
backward	B-General_Concept
compatibility	I-General_Concept
.	O
</s>
<s>
Dynamic	B-Operating_System
Data	I-Operating_System
Exchange	I-Operating_System
was	O
first	O
introduced	O
in	O
1987	O
with	O
the	O
release	O
of	O
Windows	B-Application
2.0	I-Application
as	O
a	O
method	O
of	O
interprocess	B-Operating_System
communication	I-Operating_System
so	O
that	O
one	O
program	O
could	O
communicate	O
with	O
or	O
control	O
another	O
program	O
,	O
somewhat	O
like	O
Sun	B-Protocol
's	I-Protocol
RPC	I-Protocol
(	O
Remote	O
Procedure	O
Call	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
cell	O
in	O
Microsoft	B-Application
Excel	I-Application
was	O
known	O
to	O
DDE	O
by	O
its	O
"	O
application	O
"	O
name	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
a	O
user	O
wanted	O
to	O
pull	O
a	O
value	O
from	O
Microsoft	B-Application
Excel	I-Application
which	O
was	O
contained	O
in	O
a	O
spreadsheet	O
called	O
"	O
Book1.xls	O
"	O
in	O
the	O
cell	O
in	O
the	O
first	O
row	O
and	O
first	O
column	O
,	O
the	O
application	O
would	O
be	O
"	O
Excel	B-Application
"	O
,	O
the	O
topic	O
"	O
Book1.xls	O
"	O
and	O
the	O
item	O
"	O
r1c1	O
"	O
.	O
</s>
<s>
Internal	O
changes	O
in	O
the	O
cell	O
due	O
to	O
Excel	B-Application
actions	O
would	O
then	O
be	O
signaled	O
(	O
in	O
reverse	O
)	O
to	O
the	O
calling	O
application	O
via	O
additional	O
message	O
broadcasts	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
custom	O
in-house	O
application	O
might	O
use	O
DDE	O
to	O
open	O
a	O
Microsoft	B-Application
Excel	I-Application
spreadsheet	O
and	O
fill	O
it	O
with	O
data	O
,	O
by	O
opening	O
a	O
DDE	O
conversation	O
with	O
Excel	B-Application
and	O
sending	O
it	O
DDE	O
commands	O
.	O
</s>
<s>
This	O
feature	O
has	O
mainly	O
been	O
superseded	O
by	O
the	O
Component	B-Application
Object	I-Application
Model	I-Application
suite	O
of	O
technologies	O
.	O
</s>
<s>
Microsoft	O
has	O
not	O
used	O
DDE	O
internally	O
since	O
the	O
release	O
of	O
Windows	B-Application
95	I-Application
.	O
</s>
<s>
For	O
example	O
,	O
Excel	B-Application
now	O
exposes	O
an	O
extensive	O
OLE	B-Application
Automation	I-Application
object	O
model	O
,	O
which	O
is	O
the	O
recommended	O
method	O
for	O
communicating	O
with	O
Excel	B-Application
.	O
</s>
<s>
Because	O
DDE	O
does	O
not	O
require	O
more	O
operating	O
system	O
components	O
than	O
a	O
conventional	O
Windows	O
GUI	B-Application
program	O
,	O
it	O
is	O
also	O
a	O
 [ little-used ] 	O
alternative	O
for	O
programs	O
seeking	O
to	O
minimize	O
their	O
dependencies	B-Application
.	O
</s>
<s>
Wonderware	B-Application
developed	O
an	O
extension	O
for	O
DDE	O
called	O
NetDDE	O
that	O
could	O
be	O
used	O
to	O
initiate	O
and	O
maintain	O
the	O
network	O
connections	O
needed	O
for	O
DDE	O
conversations	O
between	O
DDE-aware	O
applications	O
running	O
on	O
different	O
computers	O
in	O
a	O
network	O
and	O
transparently	O
exchange	O
data	O
.	O
</s>
<s>
Microsoft	O
licensed	O
a	O
basic	O
(	O
NetBIOS	B-Protocol
Frames	I-Protocol
only	O
)	O
version	O
of	O
the	O
product	O
for	O
inclusion	O
in	O
various	O
versions	O
of	O
Windows	O
from	O
Windows	O
for	O
Workgroups	O
to	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
In	O
addition	O
,	O
Wonderware	B-Application
also	O
sold	O
an	O
enhanced	O
version	O
of	O
NetDDE	O
to	O
their	O
own	O
customers	O
that	O
included	O
support	O
for	O
TCP/IP	B-Protocol
.	O
</s>
<s>
Basic	O
Windows	B-Application
applications	I-Application
using	O
NetDDE	O
are	O
Clipbook	B-General_Concept
Viewer	I-General_Concept
,	O
WinChat	O
and	O
Microsoft	B-Application
Hearts	I-Application
.	O
</s>
<s>
NetDDE	O
was	O
still	O
included	O
with	O
Windows	B-Application
Server	I-Application
2003	I-Application
and	O
Windows	B-Application
XP	I-Application
Service	O
Pack	O
2	O
,	O
although	O
it	O
was	O
disabled	O
by	O
default	O
.	O
</s>
<s>
It	O
has	O
been	O
removed	O
entirely	O
in	O
Windows	B-Application
Vista	I-Application
.	O
</s>
