<s>
Windows	B-Application
Driver	I-Application
Frameworks	I-Application
(	O
WDF	O
,	O
formerly	O
Windows	B-Application
Driver	I-Application
Foundation	I-Application
)	O
,	O
is	O
a	O
set	O
of	O
Microsoft	O
tools	O
and	O
libraries	O
that	O
aid	O
in	O
the	O
creation	O
of	O
device	O
drivers	O
for	O
Windows	B-Application
2000	I-Application
and	O
later	O
versions	O
of	O
Windows	O
.	O
</s>
<s>
It	O
complements	O
Windows	B-Application
Driver	I-Application
Model	I-Application
,	O
abstracting	O
away	O
much	O
of	O
the	O
boilerplate	O
complexity	O
in	O
writing	O
Windows	O
drivers	O
.	O
</s>
<s>
WDF	O
consists	O
of	O
Kernel-Mode	B-Application
Driver	I-Application
Framework	I-Application
(	O
KMDF	B-Application
)	O
and	O
User-Mode	B-Application
Driver	I-Application
Framework	I-Application
(	O
UMDF	B-Application
)	O
.	O
</s>
<s>
This	O
differs	O
markedly	O
from	O
the	O
Windows	B-Application
Driver	I-Application
Model	I-Application
(	O
WDM	O
)	O
which	O
requires	O
driver	O
developers	O
to	O
be	O
fully	O
familiar	O
with	O
many	O
complex	O
technical	O
details	O
to	O
write	O
a	O
basic	O
driver	O
.	O
</s>
<s>
Part	O
of	O
the	O
key	O
to	O
achieving	O
conceptual	O
scalability	O
is	O
that	O
KMDF	B-Application
and	O
UMDF	B-Application
use	O
an	O
"	O
opt-in	O
"	O
model	O
.	O
</s>
<s>
In	O
contrast	O
,	O
Windows	B-Application
Driver	I-Application
Model	I-Application
depends	O
on	O
the	O
driver	O
writer	O
to	O
implement	O
all	O
aspects	O
of	O
the	O
driver	O
's	O
behavior	O
.	O
</s>
