<s>
Leaf	B-Application
driver	I-Application
refers	O
to	O
a	O
device	B-Application
driver	I-Application
that	O
accesses	O
logically	O
or	O
physically	O
existent	O
devices	O
on	O
an	O
I/O	B-General_Concept
bus	I-General_Concept
,	O
and	O
implements	O
the	O
functions	O
defined	O
for	O
the	O
device	O
,	O
such	O
as	O
transferring	O
data	O
to	O
or	O
from	O
the	O
device	O
or	O
accessing	O
device	O
registers	O
.	O
</s>
<s>
Leaf	O
devices	O
(	O
those	O
requiring	O
leaf	B-Application
drivers	I-Application
)	O
are	O
typical	O
peripheral	O
devices	O
such	O
as	O
disks	B-Device
,	O
tapes	B-Architecture
,	O
network	B-Architecture
adapters	O
,	O
Framebuffer	B-Algorithm
,	O
and	O
so	O
forth	O
.	O
</s>
<s>
Drivers	O
for	O
these	O
devices	O
export	O
the	O
traditional	O
character	O
and	O
block	B-General_Concept
driver	O
interfaces	B-Application
for	O
use	O
by	O
user	O
processes	O
to	O
read	O
and	O
write	O
data	O
to	O
storage	O
or	O
communication	O
devices	O
.	O
</s>
