<s>
In	O
computing	O
,	O
file	B-Application
virtualization	I-Application
is	O
a	O
field	O
of	O
storage	B-Application
virtualization	I-Application
operating	O
on	O
computer	B-Operating_System
file	I-Operating_System
level	O
.	O
</s>
<s>
It	O
is	O
a	O
vital	O
part	O
of	O
both	O
file	B-Application
area	I-Application
network	I-Application
(	O
FAN	O
)	O
and	O
network	B-Application
file	I-Application
management	I-Application
(	O
NFM	O
)	O
concepts	O
.	O
</s>
<s>
As	O
with	O
most	O
other	O
virtualization	O
designs	O
,	O
"	O
a	O
primary	O
driver	O
behind	O
file	B-Application
virtualization	I-Application
is	O
the	O
desire	O
to	O
shield	O
users	O
and	O
administrators	O
from	O
the	O
complexity	O
of	O
the	O
underlying	O
storage	O
environment	O
.	O
</s>
<s>
Network	B-Application
file	I-Application
management	I-Application
(	O
NFM	O
)	O
is	O
a	O
data	O
storage	O
management-related	O
category	O
.	O
</s>
<s>
The	O
term	O
is	O
used	O
interchangeably	O
with	O
NAS	B-Application
virtualization	I-Application
and	O
file	B-Application
virtualization	I-Application
among	O
data	O
storage	O
industry	O
press	O
,	O
analysts	O
and	O
system	O
administrators	O
.	O
</s>
<s>
NFM	O
is	O
the	O
concept	O
of	O
creating	O
a	O
virtualization	O
layer	O
between	O
the	O
clients	O
and	O
the	O
file	O
servers	O
(	O
or	O
NAS	B-Application
devices	O
)	O
.	O
</s>
