<s>
In	O
computing	O
,	O
the	O
BIOS	B-Device
parameter	I-Device
block	I-Device
,	O
often	O
shortened	O
to	O
BPB	O
,	O
is	O
a	O
data	B-General_Concept
structure	I-General_Concept
in	O
the	O
volume	B-Device
boot	I-Device
record	I-Device
(	O
VBR	O
)	O
describing	O
the	O
physical	O
layout	O
of	O
a	O
data	B-General_Concept
storage	I-General_Concept
volume	B-Application
.	O
</s>
<s>
On	O
partitioned	O
devices	O
,	O
such	O
as	O
hard	B-Device
disks	I-Device
,	O
the	O
BPB	O
describes	O
the	O
volume	B-Application
partition	O
,	O
whereas	O
,	O
on	O
unpartitioned	O
devices	O
,	O
such	O
as	O
floppy	B-Device
disks	I-Device
,	O
it	O
describes	O
the	O
entire	O
medium	O
.	O
</s>
<s>
A	O
basic	O
BPB	O
can	O
appear	O
and	O
be	O
used	O
on	O
any	O
partition	O
,	O
including	O
floppy	B-Device
disks	I-Device
where	O
its	O
presence	O
is	O
often	O
necessary	O
;	O
however	O
,	O
certain	O
filesystems	O
also	O
make	O
use	O
of	O
it	O
in	O
describing	O
basic	O
filesystem	O
structures	O
.	O
</s>
<s>
Filesystems	O
making	O
use	O
of	O
a	O
BIOS	B-Device
parameter	I-Device
block	I-Device
include	O
FAT12	B-Application
(	O
except	O
for	O
in	O
DOS	O
1.x	O
)	O
,	O
FAT16	B-Application
,	O
FAT32	B-Application
,	O
HPFS	B-Application
,	O
and	O
NTFS	B-Application
.	O
</s>
<s>
Due	O
to	O
different	O
types	O
of	O
fields	O
and	O
the	O
amount	O
of	O
data	O
they	O
contain	O
,	O
the	O
length	O
of	O
the	O
BPB	O
is	O
different	O
for	O
FAT16	B-Application
,	O
FAT32	B-Application
,	O
and	O
NTFS	B-Application
boot	O
sectors	O
.	O
</s>
<s>
Combined	O
with	O
the	O
11-byte	O
data	B-General_Concept
structure	I-General_Concept
at	O
the	O
very	O
start	O
of	O
volume	B-Device
boot	I-Device
records	I-Device
immediately	O
preceding	O
the	O
BPB	O
or	O
EBPB	B-Device
,	O
this	O
is	O
also	O
called	O
FDC	O
descriptor	O
or	O
extended	O
FDC	O
descriptor	O
in	O
ECMA-107	O
or	O
ISO/IEC	O
9293	O
(	O
which	O
describes	O
FAT	O
as	O
for	O
flexible/floppy	O
and	O
optical	O
disk	O
cartridges	O
)	O
.	O
</s>
<s>
Format	O
of	O
standard	O
DOS	O
2.0	O
BPB	O
for	O
FAT12	B-Application
(	O
13	O
bytes	O
)	O
:	O
</s>
<s>
Format	O
of	O
standard	O
DOS	O
3.0	O
BPB	O
for	O
FAT12	B-Application
and	O
FAT16	B-Application
(	O
19	O
bytes	O
)	O
,	O
already	O
supported	O
by	O
some	O
versions	O
of	O
MS-DOS	O
2.11	O
:	O
</s>
<s>
Format	O
of	O
standard	O
DOS	O
3.2	O
BPB	O
for	O
FAT12	B-Application
and	O
FAT16	B-Application
(	O
21	O
bytes	O
)	O
:	O
</s>
<s>
Format	O
of	O
standard	O
DOS	O
3.31	O
BPB	O
for	O
FAT12	B-Application
,	O
FAT16	B-Application
and	O
FAT16B	B-Application
(	O
25	O
bytes	O
)	O
:	O
</s>
<s>
Format	O
of	O
PC	O
DOS	O
3.4	O
and	O
OS/2	O
1.0-1.1	O
Extended	B-Device
BPB	I-Device
for	O
FAT12	B-Application
,	O
FAT16	B-Application
and	O
FAT16B	B-Application
(	O
32	O
bytes	O
)	O
:	O
</s>
<s>
Format	O
of	O
DOS	O
4.0	O
and	O
OS/2	O
1.2	O
Extended	B-Device
BPB	I-Device
for	O
FAT12	B-Application
,	O
FAT16	B-Application
,	O
FAT16B	B-Application
and	O
HPFS	B-Application
(	O
51	O
bytes	O
)	O
:	O
</s>
<s>
Sector	O
offset	O
BPB	O
offset	O
Field	O
length	O
Description	O
0x00B	O
0x00	O
25	O
BYTEs	O
DOS	O
3.31	O
BPB	O
0x024	O
0x19	O
BYTE	O
Physical	O
drive	O
number	O
(	O
identical	O
to	O
DOS	O
3.4	O
EBPB	B-Device
)	O
0x025	O
0x1A	O
BYTE	O
Flags	O
etc	O
.	O
</s>
<s>
Format	O
of	O
short	O
DOS	O
7.1	O
Extended	B-Device
BIOS	I-Device
Parameter	I-Device
Block	I-Device
(	O
60	O
bytes	O
)	O
for	O
FAT32	B-Application
:	O
</s>
<s>
Format	O
of	O
full	O
DOS	O
7.1	O
Extended	B-Device
BIOS	I-Device
Parameter	I-Device
Block	I-Device
(	O
79	O
bytes	O
)	O
for	O
FAT32	B-Application
:	O
</s>
<s>
Format	O
of	O
Extended	B-Device
BPB	I-Device
for	O
NTFS	B-Application
(	O
73	O
bytes	O
)	O
:	O
</s>
<s>
Sector	O
offset	O
BPB	O
offset	O
Field	O
length	O
Description	O
0x00B	O
0x00	O
25	O
BYTEs	O
DOS	O
3.31	O
BPB	O
0x024	O
0x19	O
BYTE	O
Physical	O
drive	O
number	O
(	O
identical	O
to	O
DOS	O
3.4	O
EBPB	B-Device
)	O
0x025	O
0x1A	O
BYTE	O
Flags	O
etc	O
.	O
</s>
<s>
Nevertheless	O
,	O
the	O
volume	B-Device
boot	I-Device
record	I-Device
in	O
sector	O
0	O
is	O
organized	O
similarly	O
to	O
BPBs	O
.	O
</s>
