<s>
An	O
IFilter	B-Library
is	O
a	O
plugin	B-Application
that	O
allows	O
Microsoft	O
's	O
search	O
engines	O
to	O
index	O
various	O
file	O
formats	O
(	O
as	O
documents	O
,	O
email	O
attachments	O
,	O
database	O
records	O
,	O
audio	O
metadata	O
etc	O
.	O
)	O
</s>
<s>
Without	O
an	O
appropriate	O
IFilter	B-Library
,	O
contents	O
of	O
a	O
file	O
cannot	O
be	O
parsed	O
and	O
indexed	O
by	O
the	O
search	O
engine	O
.	O
</s>
<s>
They	O
can	O
be	O
obtained	O
as	O
standalone	O
packages	O
or	O
bundled	O
with	O
certain	O
software	O
such	O
as	O
Adobe	B-Application
Reader	I-Application
,	O
LibreOffice	B-Application
,	O
Microsoft	B-Application
Office	I-Application
and	O
OpenOffice	B-Application
.	O
</s>
<s>
It	O
also	O
refers	O
to	O
the	O
software	O
interface	O
needed	O
to	O
implement	O
such	O
plugins	B-Application
.	O
</s>
<s>
An	O
IFilter	B-Library
acts	O
as	O
a	O
plug-in	B-Application
for	O
extracting	O
full-text	O
and	O
metadata	O
for	O
search	O
engines	O
.	O
</s>
<s>
Therefore	O
,	O
it	O
looks	O
on	O
Windows	O
registry	O
for	O
an	O
appropriate	O
IFilter	B-Library
to	O
extract	O
the	O
data	O
from	O
the	O
document	O
format	O
,	O
filtering	O
out	O
embedded	O
formatting	O
and	O
any	O
other	O
non-textual	O
data	O
.	O
</s>
<s>
Windows	O
Indexing	O
Service	O
and	O
the	O
newer	O
Windows	B-Application
Search	I-Application
,	O
Windows	O
Desktop	O
Search	O
,	O
MSN	B-Application
Desktop	I-Application
Search	I-Application
,	O
Internet	O
Information	O
Server	O
,	O
SharePoint	O
Portal	O
Server	O
,	O
Windows	O
SharePoint	O
Services	O
(	O
WSS	O
)	O
,	O
Site	O
Server	O
,	O
Exchange	O
Server	O
,	O
SQL	B-Application
Server	I-Application
and	O
all	O
other	O
products	O
based	O
on	O
Microsoft	O
Search	O
technology	O
support	O
indexing	O
technology	O
.	O
</s>
<s>
Also	O
,	O
IFilters	B-Library
are	O
used	O
by	O
SQL	B-Application
Server	I-Application
as	O
a	O
component	O
of	O
the	O
SQL	B-Application
Server	I-Application
Full	O
Text	O
Search	O
service	O
.	O
</s>
