<s>
Multi-booting	B-Operating_System
is	O
the	O
act	O
of	O
installing	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
on	O
a	O
single	O
computer	O
,	O
and	O
being	O
able	O
to	O
choose	O
which	O
one	O
to	O
boot	B-Operating_System
.	O
</s>
<s>
The	O
term	O
dual-booting	B-Operating_System
refers	O
to	O
the	O
common	O
configuration	O
of	O
specifically	O
two	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Multi-booting	B-Operating_System
may	O
require	O
a	O
custom	O
boot	B-Application
loader	I-Application
.	O
</s>
<s>
Multi-booting	B-Operating_System
allows	O
more	O
than	O
one	O
operating	B-General_Concept
system	I-General_Concept
to	O
reside	O
on	O
one	O
computer	O
;	O
for	O
example	O
,	O
if	O
a	O
user	O
has	O
a	O
primary	O
operating	B-General_Concept
system	I-General_Concept
that	O
they	O
use	O
most	O
frequently	O
and	O
an	O
alternate	O
operating	B-General_Concept
system	I-General_Concept
that	O
they	O
use	O
less	O
frequently	O
.	O
</s>
<s>
Multi-booting	B-Operating_System
allows	O
a	O
new	O
operating	B-General_Concept
system	I-General_Concept
to	O
configure	O
all	O
applications	O
needed	O
and	O
migrate	O
data	O
before	O
removing	O
the	O
old	O
operating	B-General_Concept
system	I-General_Concept
,	O
if	O
desired	O
.	O
</s>
<s>
Another	O
reason	O
for	O
multi-booting	B-Operating_System
can	O
be	O
to	O
investigate	O
or	O
test	O
a	O
new	O
operating	B-General_Concept
system	I-General_Concept
without	O
switching	O
completely	O
.	O
</s>
<s>
Multi-booting	B-Operating_System
is	O
also	O
useful	O
in	O
situations	O
where	O
different	O
software	B-Application
requires	O
different	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
A	O
multi-boot	B-Operating_System
configuration	O
allows	O
a	O
user	O
to	O
use	O
all	O
of	O
their	O
software	B-Application
on	O
one	O
computer	O
.	O
</s>
<s>
This	O
is	O
often	O
accomplished	O
by	O
using	O
a	O
boot	B-Application
loader	I-Application
such	O
as	O
NTLDR	B-Application
,	O
LILO	B-Application
,	O
or	O
GRUB	B-Application
which	O
can	O
boot	B-Operating_System
more	O
than	O
one	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Multi-booting	B-Operating_System
is	O
also	O
used	O
by	O
software	B-Application
developers	I-Application
when	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
are	O
required	O
for	O
development	O
or	O
testing	O
purposes	O
.	O
</s>
<s>
Multi-booting	B-Operating_System
also	O
allows	O
a	O
user	O
to	O
switch	O
between	O
private	O
and	O
work	O
dedicated	O
systems	O
to	O
maintain	O
access	O
integrity	O
and	O
separation	O
between	O
the	O
two	O
user	O
environments	O
,	O
even	O
if	O
the	O
same	O
operating	B-General_Concept
system	I-General_Concept
is	O
used	O
for	O
each	O
of	O
them	O
.	O
</s>
<s>
A	O
possible	O
alternative	O
to	O
multi-booting	B-Operating_System
is	O
virtualization	B-General_Concept
,	O
where	O
a	O
hypervisor	B-Operating_System
is	O
used	O
to	O
host	O
one	O
or	O
more	O
virtual	B-Architecture
machines	I-Architecture
running	O
guest	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
In	O
an	O
OS/2	B-Application
dual-boot	B-Operating_System
configuration	O
,	O
the	O
C	O
drive	O
can	O
contain	O
both	O
DOS	B-Device
and	O
OS/2	B-Application
.	O
</s>
<s>
The	O
user	O
issues	O
the	O
BOOT	B-Operating_System
command	O
from	O
the	O
DOS	B-Device
or	O
OS/2	B-Application
command	O
line	O
to	O
do	O
the	O
necessary	O
copy	O
,	O
move	O
and	O
rename	O
operations	O
and	O
then	O
reboot	O
to	O
the	O
specified	O
system	O
on	O
C	O
:	O
.	O
</s>
<s>
In	O
a	O
multi-boot	B-Operating_System
computer	O
each	O
of	O
the	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
can	O
reside	O
on	O
its	O
own	O
storage	O
device	O
,	O
or	O
some	O
storage	O
devices	O
might	O
contain	O
more	O
than	O
one	O
operating	B-General_Concept
system	I-General_Concept
in	O
different	O
partitions	O
.	O
</s>
<s>
The	O
boot	B-Application
loader	I-Application
in	O
or	O
loaded	O
by	O
the	O
MBR	B-Device
displays	O
a	O
menu	O
of	O
logical	O
drives	O
and	O
loads	O
the	O
selected	O
boot	B-Application
loader	I-Application
from	O
the	O
PBR	B-Device
of	O
that	O
drive	O
.	O
</s>
<s>
An	O
example	O
of	O
a	O
computer	O
with	O
one	O
operating	B-General_Concept
system	I-General_Concept
per	O
storage	O
device	O
is	O
a	O
dual-booting	B-Operating_System
computer	O
that	O
stores	O
Windows	B-Application
on	O
one	O
disk	O
drive	O
and	O
Linux	B-Application
on	O
another	O
disk	O
drive	O
.	O
</s>
<s>
In	O
this	O
case	O
a	O
multi-booting	B-Operating_System
boot	B-Application
loader	I-Application
is	O
not	O
strictly	O
necessary	O
because	O
the	O
user	O
can	O
choose	O
to	O
enter	O
BIOS	B-Operating_System
configuration	O
immediately	O
after	O
power-up	O
and	O
make	O
the	O
desired	O
drive	O
first	O
in	O
the	O
boot-order	O
list	O
.	O
</s>
<s>
However	O
,	O
it	O
is	O
more	O
convenient	O
to	O
have	O
a	O
multi-booting	B-Operating_System
boot	B-Application
loader	I-Application
on	O
one	O
of	O
the	O
drives	O
,	O
set	O
BIOS	B-Operating_System
once	O
to	O
always	O
start	O
booting	B-Operating_System
from	O
(	O
i.e.	O
</s>
<s>
load	O
the	O
boot	B-Application
loader	I-Application
from	O
)	O
that	O
drive	O
,	O
and	O
then	O
allow	O
the	O
user	O
to	O
choose	O
an	O
operating	B-General_Concept
system	I-General_Concept
from	O
that	O
boot	B-Application
loader	I-Application
's	O
menu	O
.	O
</s>
<s>
No	O
special	O
disk	O
partitioning	O
is	O
necessary	O
when	O
each	O
operating	B-General_Concept
system	I-General_Concept
has	O
its	O
own	O
dedicated	O
disk	O
drive	O
.	O
</s>
<s>
An	O
example	O
of	O
a	O
computer	O
with	O
multiple	O
operating	B-General_Concept
systems	I-General_Concept
per	O
storage	O
device	O
is	O
a	O
dual-booting	B-Operating_System
computer	O
that	O
stores	O
both	O
Windows	B-Application
and	O
Linux	B-Application
on	O
the	O
same	O
disk	O
drive	O
but	O
where	O
the	O
BIOS	B-Operating_System
in	O
the	O
system	O
does	O
not	O
let	O
the	O
user	O
boot	B-Operating_System
individual	O
drives	O
and	O
partitions	O
.	O
</s>
<s>
In	O
this	O
case	O
a	O
multi-booting	B-Operating_System
boot	B-Application
loader	I-Application
is	O
necessary	O
.	O
</s>
<s>
Also	O
,	O
the	O
disk	O
must	O
be	O
partitioned	O
to	O
give	O
each	O
operating	B-General_Concept
system	I-General_Concept
its	O
own	O
partition	O
on	O
the	O
disk	O
drive	O
.	O
</s>
<s>
Also	O
,	O
when	O
a	O
completely	O
separate	O
operating	B-General_Concept
system	I-General_Concept
is	O
used	O
partitions	O
may	O
need	O
to	O
be	O
formatted	O
to	O
a	O
different	O
format	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
a	O
user	O
intends	O
to	O
install	O
both	O
Windows	B-Application
and	O
Linux	B-Application
,	O
then	O
the	O
Windows	B-Application
partition	O
will	O
be	O
most	O
likely	O
formatted	O
in	O
the	O
NTFS	B-Application
format	O
as	O
Windows	B-Application
cannot	O
run	O
off	O
of	O
ext4	B-Application
,	O
and	O
the	O
Linux	B-Application
partition	O
will	O
most	O
likely	O
be	O
formatted	O
in	O
the	O
ext4	B-Application
file	O
format	O
as	O
Linux	B-Application
cannot	O
run	O
off	O
of	O
NTFS	B-Application
.	O
</s>
<s>
However	O
,	O
if	O
a	O
user	O
intends	O
to	O
dual-boot	B-Operating_System
two	O
versions	O
of	O
Windows	B-Application
(	O
i.e.	O
</s>
<s>
Windows	B-Device
7	I-Device
and	O
Windows	B-Application
Vista	I-Application
)	O
or	O
two	O
versions	O
of	O
Linux	B-Application
(	O
i.e.	O
</s>
<s>
Linux	B-Application
Mint	I-Application
and	O
Ubuntu	B-Operating_System
Linux	I-Operating_System
)	O
,	O
then	O
the	O
same	O
file	B-Application
system	I-Application
(	O
e.g.	O
</s>
<s>
NTFS	B-Application
or	O
ext4	B-Application
)	O
can	O
be	O
used	O
across	O
both	O
drives	O
and	O
partitions	O
.	O
</s>
<s>
The	O
basic	O
concept	O
involves	O
partitioning	O
a	O
disk	O
to	O
accommodate	O
each	O
planned	O
installation	O
,	O
usually	O
including	O
separate	O
partitions	O
for	O
boot	B-Operating_System
,	O
root	O
,	O
data	O
storage	O
and	O
backups	O
.	O
</s>
<s>
An	O
MBR	B-Device
loader	O
,	O
such	O
as	O
Air-Boot	O
,	O
replaces	O
the	O
standard	O
boot	B-Operating_System
code	O
in	O
track	O
0	O
with	O
code	O
that	O
displays	O
a	O
selection	O
menu	O
and	O
loads	O
the	O
selected	O
system	O
.	O
</s>
<s>
Some	O
,	O
e.g.	O
,	O
Air-Boot	O
,	O
can	O
be	O
configured	O
either	O
automatically	O
or	O
by	O
the	O
user	O
at	O
boot	B-Operating_System
time	I-Operating_System
,	O
rather	O
than	O
requiring	O
an	O
external	O
configuration	O
menu	O
.	O
</s>
<s>
Linux	B-Application
loaders	I-Application
such	O
as	O
GRUB	B-Application
and	O
LILO	B-Application
,	O
can	O
reside	O
in	O
the	O
MBR	B-Device
or	O
in	O
a	O
PBR	B-Device
.	O
</s>
<s>
They	O
use	O
configuration	O
files	O
in	O
/boot	O
to	O
control	O
their	O
selection	O
menus	O
,	O
</s>
<s>
The	O
OS/2	B-Application
Boot	B-Application
Manager	I-Application
must	O
be	O
installed	O
in	O
a	O
primary	O
partition	O
.	O
</s>
<s>
The	O
OS/2	B-Application
partitioning	O
utilities	O
can	O
configure	O
up	O
to	O
four	O
systems	O
in	O
the	O
menu	O
,	O
each	O
of	O
which	O
can	O
be	O
either	O
in	O
a	O
primary	O
partition	O
or	O
in	O
a	O
logical	O
volume	O
within	O
the	O
extended	O
logical	O
partition	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
include	O
a	O
boot	B-Application
loader	I-Application
such	O
as	O
GRUB	B-Application
in	O
the	O
OS/2	B-Application
Boot	B-Application
Manager	I-Application
menu	O
,	O
and	O
it	O
is	O
possible	O
to	O
include	O
the	O
OS/2	B-Application
Boot	B-Application
Manager	I-Application
in	O
the	O
menu	O
for	O
another	O
boot	B-Application
loader	I-Application
.	O
</s>
<s>
Newer	O
loaders	O
such	O
as	O
Air-Boot	O
,	O
GRUB	B-Application
and	O
LILO	B-Application
offer	O
more	O
flexibility	O
.	O
</s>
<s>
One	O
popular	O
multi-boot	B-Operating_System
configuration	O
is	O
to	O
dual-boot	B-Operating_System
Linux	B-Application
and	O
Windows	B-Application
operating	I-Application
systems	I-Application
,	O
each	O
contained	O
within	O
its	O
own	O
partition	O
.	O
</s>
<s>
Windows	B-Application
does	O
not	O
facilitate	O
or	O
support	O
multi-boot	B-Operating_System
systems	I-Operating_System
,	O
other	O
than	O
allowing	O
for	O
partition-specific	O
installations	O
,	O
and	O
no	O
choice	O
of	O
boot	B-Application
loader	I-Application
is	O
offered	O
.	O
</s>
<s>
However	O
,	O
most	O
current	O
Linux	B-Application
installers	O
accommodate	O
dual-booting	B-Operating_System
(	O
although	O
some	O
knowledge	O
of	O
partitions	O
is	O
desirable	O
)	O
.	O
</s>
<s>
Commonly	O
installations	O
proceed	O
without	O
incident	O
but	O
upon	O
restart	O
,	O
the	O
boot	B-Application
loader	I-Application
will	O
recognize	O
only	O
one	O
of	O
the	O
two	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
There	O
are	O
some	O
advantages	O
to	O
installing	O
a	O
Linux	B-Application
boot	O
manager/loader	O
(	O
usually	O
GRUB	B-Application
)	O
as	O
the	O
primary	O
bootloader	B-Application
pointed	O
to	O
by	O
the	O
master	B-Device
boot	I-Device
record	I-Device
.	O
</s>
<s>
Windows	B-Application
operating	I-Application
systems	I-Application
will	O
be	O
found	O
by	O
properly	O
installed	O
Linux	B-Application
bootloaders	B-Application
,	O
but	O
Windows	B-Operating_System
boot	I-Operating_System
managers	I-Operating_System
do	O
not	O
recognize	O
Linux	B-Application
installations	O
(	O
nor	O
does	O
Windows	B-Application
deal	O
natively	O
with	O
Linux	B-Application
file	B-Application
systems	I-Application
)	O
.	O
</s>
<s>
The	O
MBR	B-Device
boot	B-Operating_System
code	O
can	O
be	O
backed	O
up	O
and	O
restored	O
with	O
dd	B-Application
,	O
available	O
on	O
System	B-Application
Rescue	I-Application
CD	I-Application
.	O
</s>
<s>
It	O
is	O
often	O
recommended	O
that	O
Windows	B-Application
be	O
installed	O
to	O
the	O
first	O
primary	O
partition	O
.	O
</s>
<s>
The	O
boot	B-Operating_System
loaders	I-Operating_System
of	O
both	O
Windows	B-Application
and	O
Linux	B-Application
identify	O
partitions	O
with	O
a	O
number	O
derived	O
by	O
counting	O
the	O
partitions	O
.	O
</s>
<s>
(	O
Note	O
,	O
both	O
Windows	B-Application
and	O
Linux	B-Application
count	O
the	O
partitions	O
according	O
to	O
the	O
ordering	O
of	O
the	O
partitions	O
in	O
the	O
partition	O
table	O
,	O
which	O
may	O
be	O
different	O
from	O
the	O
order	O
of	O
the	O
partitions	O
on	O
the	O
disk	O
.	O
)	O
</s>
<s>
If	O
the	O
number	O
of	O
the	O
system	O
partition	O
changes	O
,	O
it	O
requires	O
boot	B-Application
loader	I-Application
reconfiguration	O
in	O
order	O
for	O
an	O
operating	B-General_Concept
system	I-General_Concept
to	O
boot	B-Operating_System
and	O
function	O
properly	O
.	O
</s>
<s>
Windows	B-Application
must	O
be	O
installed	O
into	O
a	O
primary	O
partition	O
(	O
and	O
in	O
older	O
systems	O
this	O
must	O
be	O
the	O
first	O
partition	O
)	O
.	O
</s>
<s>
Linux	B-Application
can	O
be	O
installed	O
into	O
a	O
partition	O
in	O
any	O
position	O
on	O
the	O
hard	O
drive	O
and	O
can	O
also	O
be	O
installed	O
into	O
logical	O
partitions	O
(	O
within	O
the	O
extended	B-Application
partition	I-Application
)	O
.	O
</s>
<s>
If	O
Linux	B-Application
is	O
installed	O
into	O
a	O
logical	O
partition	O
within	O
the	O
extended	B-Application
partition	I-Application
,	O
it	O
is	O
unaffected	O
by	O
changes	O
in	O
the	O
primary	O
partitions	O
.	O
</s>
<s>
An	O
alternative	O
to	O
storing	O
GRUB	B-Application
in	O
the	O
MBR	B-Device
is	O
keeping	O
Windows	B-Application
 '	O
or	O
other	O
generic	O
PC	O
boot	B-Operating_System
code	O
in	O
the	O
MBR	B-Device
,	O
and	O
installing	O
GRUB	B-Application
or	O
another	O
bootloader	B-Application
into	O
a	O
primary	O
partition	O
other	O
than	O
that	O
of	O
Windows	B-Application
,	O
thus	O
keeping	O
the	O
MBR	B-Device
neutral	O
.	O
</s>
<s>
Operating	B-General_Concept
system	I-General_Concept
selection	O
at	O
boot	B-Operating_System
time	I-Operating_System
consequently	O
depends	O
on	O
the	O
bootloader	B-Application
configured	O
within	O
the	O
primary	O
partition	O
that	O
has	O
the	O
boot	B-Operating_System
or	O
"	O
active	O
"	O
flag	O
set	O
on	O
its	O
partition	O
table	O
entry	O
,	O
which	O
could	O
be	O
a	O
bootloader	B-Application
of	O
DOS	B-Device
,	O
OS/2	B-Application
,	O
eComStation	B-Device
,	O
ArcaOS	B-Device
or	O
BSD	B-Operating_System
,	O
in	O
addition	O
to	O
Linux	B-Application
or	O
Windows	B-Application
.	O
</s>
<s>
With	O
the	O
boot	B-Operating_System
flag	O
set	O
on	O
the	O
Windows	B-Application
primary	O
,	O
the	O
Windows	B-Operating_System
Boot	I-Operating_System
Manager	I-Operating_System
can	O
be	O
used	O
to	O
chainload	B-Operating_System
another	O
installed	O
bootloader	B-Application
through	O
use	O
of	O
a	O
program	O
like	O
EasyBCD	B-Application
.	O
</s>
<s>
This	O
means	O
the	O
active	O
partition	O
's	O
boot	B-Application
manager	I-Application
will	O
first	O
prompt	O
the	O
user	O
for	O
selection	O
what	O
OS	O
to	O
boot	B-Operating_System
,	O
then	O
load	O
another	O
if	O
necessary	O
,	O
such	O
as	O
GRUB	B-Application
,	O
even	O
a	O
bootloader	B-Application
installed	O
to	O
a	O
logical	O
partition	O
,	O
and	O
then	O
GRUB	B-Application
will	O
load	O
the	O
Linux	B-Application
kernel	O
as	O
it	O
normally	O
would	O
were	O
GRUB	B-Application
installed	O
to	O
the	O
MBR	B-Device
.	O
</s>
<s>
The	O
active	O
partition	O
could	O
also	O
be	O
one	O
that	O
exists	O
for	O
no	O
purpose	O
other	O
than	O
choosing	O
an	O
operating	B-General_Concept
system	I-General_Concept
to	O
boot	B-Operating_System
,	O
such	O
as	O
the	O
boot	B-Application
manager	I-Application
that	O
shipped	O
with	O
IBM	O
's	O
OS/2	B-Application
Warp	O
and	O
its	O
derivatives	O
.	O
</s>
<s>
Boot	B-Operating_System
Camp	O
allows	O
owners	O
of	O
Intel-based	B-Device
Apple	I-Device
Macintosh	I-Device
computers	I-Device
to	O
install	O
Windows	B-Application
XP	I-Application
,	O
Vista	B-Application
,	O
7	O
,	O
8	O
,	O
and	O
10	O
on	O
their	O
Macs	O
.	O
</s>
<s>
The	B-Application
software	I-Application
comes	O
bundled	O
with	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
since	O
version	O
10.5	O
(	O
Leopard	O
)	O
.	O
</s>
<s>
Boot	B-Operating_System
Camp	O
allows	O
non-destructive	O
disk	O
partitioning	O
and	O
resizing	O
of	O
HFS+	B-Application
filesystems	B-Application
,	O
boot	B-Operating_System
menu	I-Operating_System
options	O
,	O
and	O
an	O
option	O
to	O
burn	O
a	O
CD	O
with	O
necessary	O
device	B-Application
drivers	I-Application
.	O
</s>
<s>
Since	O
Windows	B-Application
XP	I-Application
is	O
incompatible	O
with	O
Extensible	B-Architecture
Firmware	I-Architecture
Interface	I-Architecture
(	O
the	O
successor	O
to	O
legacy	B-Operating_System
BIOS	I-Operating_System
)	O
,	O
the	O
firmware	O
on	O
early	O
Intel	B-Device
Macs	I-Device
needs	O
to	O
be	O
updated	O
to	O
support	O
BIOS	B-Operating_System
emulation	O
first	O
.	O
</s>
<s>
BIOS	B-Operating_System
emulation	O
is	O
achieved	O
with	O
a	O
compatibility	O
support	O
module	O
(	O
CSM	O
)	O
.	O
</s>
<s>
Apple	O
does	O
not	O
support	O
non-Windows	O
partition	O
formats	O
or	O
drivers	O
so	O
therefore	O
configuring	O
other	O
operating	B-General_Concept
systems	I-General_Concept
is	O
not	O
directly	O
possible	O
through	O
Boot	B-Operating_System
Camp	O
itself	O
.	O
</s>
<s>
However	O
,	O
any	O
operating	B-General_Concept
system	I-General_Concept
which	O
can	O
utilize	O
the	O
BIOS	B-Operating_System
emulation	O
of	O
Intel	O
Macintosh	O
can	O
be	O
made	O
to	O
work	O
,	O
including	O
non-XP	O
versions	O
of	O
Windows	B-Application
.	O
</s>
<s>
The	O
Ubuntu	B-Operating_System
Linux	I-Operating_System
distribution	I-Operating_System
is	O
particularly	O
popular	O
for	O
this	O
purpose	O
because	O
they	O
provide	O
an	O
option	O
to	O
use	O
proprietary	B-Application
device	B-Application
drivers	I-Application
along	O
with	O
open	O
source	O
drivers	O
.	O
</s>
