<s>
The	O
BIOS	B-Device
boot	I-Device
partition	I-Device
is	O
a	O
partition	B-Application
on	O
a	O
data	B-General_Concept
storage	I-General_Concept
device	I-General_Concept
that	O
GNU	B-Application
GRUB	I-Application
uses	O
on	O
legacy	O
BIOS-based	O
personal	B-Device
computers	I-Device
in	O
order	O
to	O
boot	B-Operating_System
an	O
operating	B-General_Concept
system	I-General_Concept
,	O
when	O
the	O
actual	O
boot	B-Operating_System
device	O
contains	O
a	O
GUID	B-Application
Partition	I-Application
Table	I-Application
(	O
GPT	O
)	O
.	O
</s>
<s>
Such	O
a	O
layout	O
is	O
sometimes	O
referred	O
to	O
as	O
BIOS/GPT	O
boot	B-Operating_System
.	O
</s>
<s>
A	O
BIOS	B-Device
boot	I-Device
partition	I-Device
is	O
needed	O
on	O
GPT-partitioned	O
storage	O
devices	O
to	O
hold	O
the	O
second	O
stages	O
of	O
GRUB	B-Application
.	O
</s>
<s>
On	O
traditional	O
MBR-partitioned	O
devices	O
,	O
the	O
disk	B-Application
sectors	I-Application
immediately	O
following	O
the	O
first	O
are	O
usually	O
unused	O
,	O
as	O
the	O
partitioning	B-Application
scheme	O
does	O
not	O
designate	O
them	O
for	O
any	O
special	O
purpose	O
and	O
partitioning	B-Application
tools	O
avoid	O
them	O
for	O
alignment	O
purposes	O
.	O
</s>
<s>
On	O
GPT-based	O
devices	O
,	O
the	O
sectors	O
hold	O
the	O
actual	O
partition	B-Application
table	O
,	O
necessitating	O
the	O
use	O
of	O
an	O
extra	O
partition	B-Application
.	O
</s>
<s>
On	O
MBR-partitioned	O
disks	O
,	O
boot	B-Application
loaders	I-Application
are	O
usually	O
implemented	O
so	O
the	O
portion	O
of	O
their	O
code	O
stored	O
within	O
the	O
MBR	B-Device
,	O
which	O
cannot	O
hold	O
more	O
than	O
512	B-Application
bytes	I-Application
,	O
operates	O
as	O
a	O
first	O
stage	O
that	O
serves	O
primarily	O
to	O
load	O
a	O
more	O
sophisticated	O
second	O
stage	O
,	O
which	O
is	O
,	O
for	O
example	O
,	O
capable	O
of	O
reading	O
and	O
loading	O
an	O
operating	B-Operating_System
system	I-Operating_System
kernel	I-Operating_System
from	O
a	O
file	B-Application
system	I-Application
.	O
</s>
<s>
When	O
used	O
,	O
the	O
BIOS	B-Device
boot	I-Device
partition	I-Device
contains	O
the	O
second	O
stage	O
of	O
the	O
boot	B-Application
loader	I-Application
program	O
,	O
such	O
as	O
the	O
GRUB2	O
;	O
the	O
first	O
stage	O
is	O
the	O
code	O
that	O
is	O
contained	O
within	O
the	O
Master	B-Device
Boot	I-Device
Record	I-Device
(	O
MBR	B-Device
)	O
.	O
</s>
<s>
Use	O
of	O
this	O
partition	B-Application
is	O
not	O
the	O
only	O
way	O
BIOS-based	O
boot	B-Operating_System
can	O
be	O
performed	O
while	O
using	O
GPT-partitioned	O
hard	O
drives	O
;	O
however	O
,	O
complex	O
boot	B-Application
loaders	I-Application
such	O
as	O
GRUB	B-Application
2	I-Application
cannot	O
fit	O
entirely	O
within	O
the	O
confines	O
of	O
the	O
MBR	B-Device
's	O
398	O
to	O
446	O
bytes	O
of	O
space	O
,	O
thus	O
they	O
need	O
an	O
ancillary	O
storage	O
space	O
.	O
</s>
<s>
On	O
MBR	B-Device
disks	O
,	O
such	O
boot	B-Application
loaders	I-Application
typically	O
use	O
the	O
sectors	O
immediately	O
following	O
the	O
MBR	B-Device
for	O
this	O
storage	O
;	O
that	O
space	O
is	O
usually	O
known	O
as	O
the	O
"	O
MBR	B-Device
gap	O
"	O
.	O
</s>
<s>
No	O
equivalent	O
unused	O
space	O
exists	O
on	O
GPT	B-Application
disks	I-Application
,	O
and	O
the	O
BIOS	B-Device
boot	I-Device
partition	I-Device
is	O
a	O
way	O
to	O
officially	O
allocate	O
such	O
space	O
for	O
use	O
by	O
the	O
boot	B-Application
loader	I-Application
.	O
</s>
<s>
The	O
globally	O
unique	O
identifier	O
(	O
GUID	O
)	O
for	O
the	O
BIOS	B-Device
boot	I-Device
partition	I-Device
in	O
the	O
GPT	O
scheme	O
is	O
(	O
which	O
,	O
when	O
written	O
to	O
a	O
GPT	O
in	O
the	O
required	O
little	O
endian	O
fields	O
,	O
forms	O
the	O
ASCII	O
string	O
"	O
Hah	B-Device
!	I-Device
IdontNeedEFI	I-Device
"	O
)	O
.	O
</s>
<s>
In	O
the	O
context	O
of	O
GPT	O
on	O
a	O
BIOS-based	O
computer	O
,	O
a	O
BIOS	B-Device
boot	I-Device
partition	I-Device
is	O
similar	O
in	O
some	O
respects	O
to	O
the	O
EFI	B-Device
system	I-Device
partition	I-Device
,	O
which	O
is	O
used	O
by	O
systems	O
based	O
on	O
EFI	B-Architecture
.	O
</s>
<s>
The	O
EFI	B-Device
System	I-Device
partition	I-Device
holds	O
a	O
filesystem	B-Application
and	O
files	O
used	O
by	O
the	O
UEFI	B-Architecture
,	O
while	O
the	O
BIOS	B-Device
boot	I-Device
partition	I-Device
is	O
used	O
in	O
BIOS-based	O
systems	O
and	O
accessed	O
without	O
a	O
filesystem	B-Application
by	O
holding	O
raw	O
binary	O
code	O
.	O
</s>
<s>
The	O
size	O
requirements	O
for	O
a	O
BIOS	B-Device
boot	I-Device
partition	I-Device
are	O
quite	O
low	O
so	O
it	O
can	O
be	O
as	O
small	O
as	O
about	O
30KiB	O
;	O
however	O
,	O
as	O
future	O
boot	B-Application
loaders	I-Application
might	O
require	O
more	O
space	O
,	O
1MiB	O
might	O
be	O
a	O
reasonable	O
BIOS	B-Device
boot	I-Device
partition	I-Device
size	O
.	O
</s>
<s>
Due	O
to	O
the	O
1	O
MiB	O
partition	B-Application
alignment	O
policies	O
used	O
by	O
most	O
modern	O
disk	B-Application
partitioning	I-Application
tools	O
to	O
provide	O
optimum	O
performance	O
with	O
Advanced	B-Device
Format	I-Device
disks	O
,	O
SSD	B-Device
devices	I-Device
and	O
certain	O
RAID	B-Architecture
configurations	O
,	O
some	O
room	O
is	O
left	O
allowing	O
the	O
placement	O
of	O
a	O
BIOS	B-Device
boot	I-Device
partition	I-Device
between	O
the	O
GPT	O
and	O
the	O
first	O
partition	B-Application
aligned	O
that	O
way	O
.	O
</s>
<s>
If	O
created	O
by	O
utilizing	O
that	O
free	O
space	O
,	O
the	O
BIOS	B-Device
boot	I-Device
partition	I-Device
would	O
be	O
out	O
of	O
the	O
GPT	O
alignment	O
specification	O
,	O
but	O
that	O
is	O
not	O
very	O
important	O
since	O
it	O
is	O
written	O
to	O
very	O
infrequently	O
.	O
</s>
<s>
The	O
following	O
utilities	O
are	O
known	O
to	O
support	O
BIOS	B-Device
boot	I-Device
partitions	I-Device
:	O
</s>
<s>
GNU	B-Application
Parted	I-Application
(	O
2.0	O
or	O
later	O
)	O
.	O
</s>
<s>
GParted	B-Application
,	O
the	O
front-end	O
to	O
GNU	B-Application
Parted	I-Application
.	O
</s>
<s>
gpt(8 )	O
partition	B-Application
editor	O
in	O
NetBSD	B-Device
(	O
5.0	O
or	O
later	O
)	O
.	O
</s>
