<s>
CoWord	B-Operating_System
is	O
a	O
software	O
add-on	O
to	O
Microsoft	B-Application
Word	I-Application
to	O
enable	O
multiple	O
users	O
to	O
edit	O
the	O
same	O
document	O
over	O
the	O
Internet	O
with	O
MS	B-Application
Word	I-Application
.	O
</s>
<s>
It	O
is	O
a	O
part	O
of	O
the	O
CoOffice	O
suite	O
of	O
collaboration	O
tools	O
for	O
Microsoft	B-Application
Office	I-Application
.	O
</s>
<s>
CoWord	B-Operating_System
can	O
be	O
considered	O
as	O
a	O
collaborative	B-Application
real-time	I-Application
editor	I-Application
,	O
with	O
the	O
editor	O
being	O
MS	B-Application
Word	I-Application
(	O
which	O
is	O
not	O
distributed	O
with	O
CoWord	B-Operating_System
)	O
.	O
</s>
<s>
To	O
use	O
CoWord	B-Operating_System
,	O
users	O
need	O
to	O
supply	O
their	O
own	O
copies	O
of	O
MS	B-Application
Word	I-Application
.	O
</s>
<s>
As	O
of	O
August	O
2010	O
,	O
CoWord	B-Operating_System
has	O
become	O
CodoxWord	O
,	O
released	O
by	O
CodoxWare	O
.	O
</s>
<s>
One	O
of	O
the	O
main	O
challenges	O
in	O
building	O
collaborative	B-Application
real-time	I-Application
editors	I-Application
is	O
in	O
concurrency	B-Operating_System
control	I-Operating_System
.	O
</s>
<s>
The	O
concurrency	B-Operating_System
control	I-Operating_System
technology	O
used	O
by	O
CoWord	B-Operating_System
is	O
Operational	B-Operating_System
transformation	I-Operating_System
.	O
</s>
<s>
Operational	B-Operating_System
transformation	I-Operating_System
(	O
OT	O
)	O
can	O
incorporate	O
concurrent	O
changes	O
made	O
to	O
replicas	O
of	O
the	O
same	O
document	O
.	O
</s>
<s>
Other	O
known	O
systems	O
based	O
on	O
Operational	B-Operating_System
transformation	I-Operating_System
are	O
:	O
ACE	B-Language
,	O
Gobby	O
,	O
and	O
Subethaedit	B-Operating_System
.	O
</s>
<s>
In	O
CoWord	B-Operating_System
,	O
OT	O
is	O
implemented	O
in	O
a	O
module	O
called	O
Generic	O
Collaborative	O
Engine	O
(	O
GCE	O
)	O
.	O
</s>
<s>
GCE	O
is	O
also	O
provided	O
as	O
a	O
library	O
package	O
,	O
allowing	O
other	O
developers	O
to	O
create	O
real-time	B-Application
collaborative	I-Application
editing	I-Application
systems	O
without	O
having	O
to	O
implement	O
OT	O
.	O
</s>
