<s>
In	O
computer	B-Application
file	I-Application
systems	I-Application
,	O
a	O
block	B-Application
allocation	I-Application
map	I-Application
is	O
a	O
data	B-General_Concept
structure	I-General_Concept
used	O
to	O
track	O
disk	B-General_Concept
blocks	I-General_Concept
that	O
are	O
considered	O
"	O
in	O
use	O
"	O
.	O
</s>
<s>
CP/M	B-Application
used	O
a	O
block	B-Application
allocation	I-Application
map	I-Application
in	O
its	O
directory	O
.	O
</s>
<s>
A	O
benefit	O
of	O
this	O
method	O
is	O
the	O
possibility	O
to	O
use	O
sparse	B-General_Concept
files	I-General_Concept
by	O
declaring	O
a	O
large	O
file	O
size	O
but	O
only	O
allocating	O
blocks	O
that	O
are	O
actually	O
used	O
.	O
</s>
<s>
The	O
Commodore	B-Device
DOS	I-Device
used	O
a	O
similarly	O
named	O
but	O
significantly	O
different	O
noting	O
.	O
</s>
