<s>
Metadata	B-General_Concept
controller	I-General_Concept
(	O
or	O
MDC	O
)	O
is	O
a	O
storage	O
area	O
network	O
(	O
SAN	O
)	O
technology	O
for	O
managing	O
file	B-Application
locking	I-Application
,	O
space	O
allocation	O
and	O
data	O
access	O
authorization	O
.	O
</s>
<s>
This	O
is	O
needed	O
when	O
several	O
clients	O
are	O
given	O
block	O
level	O
access	O
to	O
the	O
same	O
disk	O
volume	O
,	O
data	B-General_Concept
storage	I-General_Concept
sharing	O
.	O
</s>
