<s>
Oracle	B-Operating_System
VM	I-Operating_System
VirtualBox	I-Operating_System
(	O
formerly	O
Sun	B-Operating_System
VirtualBox	I-Operating_System
,	O
Sun	B-Operating_System
xVM	I-Operating_System
VirtualBox	I-Operating_System
and	O
InnoTek	B-Operating_System
VirtualBox	I-Operating_System
)	O
is	O
a	O
type-2	O
hypervisor	B-Operating_System
for	O
x86	B-General_Concept
virtualization	I-General_Concept
developed	O
by	O
Oracle	B-Application
Corporation	I-Application
.	O
</s>
<s>
VirtualBox	B-Operating_System
was	O
originally	O
created	O
by	O
InnoTek	B-Operating_System
Systemberatung	O
GmbH	O
,	O
which	O
was	O
acquired	O
by	O
Sun	O
Microsystems	O
in	O
2008	O
,	O
which	O
was	O
in	O
turn	O
acquired	O
by	O
Oracle	B-Application
in	O
2010	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
may	O
be	O
installed	O
on	O
Microsoft	B-Application
Windows	I-Application
,	O
macOS	B-Application
,	O
Linux	B-Application
,	O
Solaris	B-Application
and	O
OpenSolaris	B-Operating_System
.	O
</s>
<s>
There	O
are	O
also	O
ports	O
to	O
FreeBSD	B-Operating_System
and	O
Genode	B-Language
.	O
</s>
<s>
It	O
supports	O
the	O
creation	O
and	O
management	O
of	O
guest	O
virtual	B-Architecture
machines	I-Architecture
running	O
Windows	B-Application
,	O
Linux	B-Application
,	O
BSD	B-Operating_System
,	O
OS/2	B-Application
,	O
Solaris	B-Application
,	O
Haiku	B-Language
,	O
and	O
OSx86	B-Operating_System
,	O
as	O
well	O
as	O
limited	O
virtualization	O
of	O
guests	O
on	O
Apple	O
hardware	O
.	O
</s>
<s>
For	O
some	O
guest	O
operating	O
systems	O
,	O
a	O
"	O
Guest	B-Operating_System
Additions	I-Operating_System
"	O
package	O
of	O
device	O
drivers	O
and	O
system	O
applications	O
is	O
available	O
,	O
which	O
typically	O
improves	O
performance	O
,	O
especially	O
that	O
of	O
graphics	O
,	O
and	O
allows	O
changing	O
the	O
resolution	O
of	O
the	O
guest	O
OS	O
automatically	O
when	O
the	O
window	O
of	O
the	O
virtual	B-Architecture
machine	I-Architecture
on	O
the	O
host	O
OS	O
is	O
resized	O
.	O
</s>
<s>
Released	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
and	O
,	O
optionally	O
,	O
the	O
CDDL	B-Application
for	O
most	O
files	O
of	O
the	O
source	O
distribution	O
,	O
VirtualBox	B-Operating_System
is	O
free	B-License
and	I-License
open-source	I-License
software	I-License
,	O
though	O
the	O
Extension	O
Pack	O
is	O
proprietary	B-Application
software	I-Application
.	O
</s>
<s>
The	O
License	O
to	O
VirtualBox	B-Operating_System
was	O
relicensed	O
to	O
GPLv3	O
with	O
linking	O
exceptions	O
to	O
the	O
CDDL	B-Application
and	O
other	O
GPL-incompatible	O
licenses	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
was	O
first	O
offered	O
by	O
InnoTek	B-Operating_System
Systemberatung	O
GmbH	O
,	O
a	O
Germany	O
company	O
based	O
in	O
Weinstadt	O
,	O
under	O
a	O
proprietary	B-Application
software	I-Application
license	I-Application
,	O
making	O
one	O
version	O
of	O
the	O
product	O
available	O
at	O
no	O
cost	O
for	O
personal	O
or	O
evaluation	O
use	O
,	O
subject	O
to	O
the	O
VirtualBox	B-Operating_System
Personal	O
Use	O
and	O
Evaluation	O
License	O
(	O
PUEL	O
)	O
.	O
</s>
<s>
In	O
January	O
2007	O
,	O
based	O
on	O
counsel	O
by	O
LiSoG	O
,	O
InnoTek	B-Operating_System
released	O
VirtualBox	B-Operating_System
Open	O
Source	O
Edition	O
(	O
OSE	O
)	O
as	O
free	B-License
and	I-License
open-source	I-License
software	I-License
,	O
subject	O
to	O
the	O
requirements	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
,	O
version	O
2	O
.	O
</s>
<s>
InnoTek	B-Operating_System
also	O
contributed	O
to	O
the	O
development	O
of	O
OS/2	B-Application
and	O
Linux	B-Application
support	O
in	O
virtualization	O
and	O
OS/2	B-Application
ports	O
of	O
products	O
from	O
Connectix	O
which	O
were	O
later	O
acquired	O
by	O
Microsoft	O
.	O
</s>
<s>
Specifically	O
,	O
InnoTek	B-Operating_System
developed	O
the	O
"	O
additions	O
"	O
code	O
in	O
both	O
Windows	B-Application
Virtual	I-Application
PC	I-Application
and	O
Microsoft	B-General_Concept
Virtual	I-General_Concept
Server	I-General_Concept
,	O
which	O
enables	O
various	O
host	O
–	O
guest	O
OS	O
interactions	O
like	O
shared	O
clipboards	O
or	O
dynamic	O
viewport	O
resizing	O
.	O
</s>
<s>
Sun	O
Microsystems	O
acquired	O
InnoTek	B-Operating_System
in	O
February	O
2008	O
.	O
</s>
<s>
Following	O
the	O
acquisition	O
of	O
Sun	O
Microsystems	O
by	O
Oracle	B-Application
Corporation	I-Application
in	O
January	O
2010	O
,	O
the	O
product	O
was	O
re-branded	O
as	O
"	O
Oracle	B-Operating_System
VM	I-Operating_System
VirtualBox	I-Operating_System
"	O
.	O
</s>
<s>
In	O
December	O
2019	O
,	O
VirtualBox	B-Operating_System
started	O
supporting	O
only	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
,	O
dropping	O
support	O
for	O
Software-based	O
one	O
.	O
</s>
<s>
The	O
PUEL/OSE	O
separation	O
was	O
abandoned	O
in	O
favor	O
of	O
an	O
open	O
source	O
base	O
product	O
and	O
a	O
closed	B-Application
source	I-Application
extension	O
pack	O
that	O
can	O
be	O
installed	O
on	O
top	O
of	O
the	O
base	O
product	O
.	O
</s>
<s>
Virtual	B-Architecture
machine	I-Architecture
groups	O
–	O
allows	O
management	O
of	O
a	O
group	O
of	O
virtual	B-Architecture
machines	I-Architecture
as	O
a	O
single	O
unit	O
(	O
power	O
them	O
on	O
or	O
off	O
,	O
take	O
snapshots	O
,	O
etc	O
.	O
)	O
</s>
<s>
It	O
is	O
supported	O
by	O
any	O
Windows	B-Application
version	O
starting	O
from	O
Windows	B-Application
8	I-Application
,	O
any	O
Linux	B-Application
kernel	O
starting	O
from	O
2.6.31	O
and	O
Mac	B-Application
OS	I-Application
X	O
starting	O
from	O
version	O
10.7.4	O
.	O
</s>
<s>
The	O
core	O
package	O
is	O
,	O
since	O
version	O
4	O
in	O
December	O
2010	O
,	O
free	B-Application
software	I-Application
under	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
version	O
2	O
(	O
GPLv2	O
)	O
.	O
</s>
<s>
The	O
separate	O
"	O
VirtualBox	B-Operating_System
Oracle	B-Operating_System
VM	I-Operating_System
VirtualBox	I-Operating_System
extension	O
pack	O
"	O
providing	O
support	O
for	O
USB	B-Protocol
2.0	O
and	O
3.0	O
devices	O
,	O
Remote	B-Protocol
Desktop	I-Protocol
Protocol	I-Protocol
(	O
RDP	B-Protocol
)	O
,	O
disk	O
encryption	O
,	O
NVMe	B-Application
and	O
Preboot	B-Device
Execution	I-Device
Environment	I-Device
(	O
PXE	B-Device
)	O
boot	O
is	O
under	O
a	O
proprietary	B-Application
license	I-Application
,	O
called	O
Personal	O
Use	O
and	O
Evaluation	O
License	O
(	O
PUEL	O
)	O
,	O
which	O
permits	O
use	O
of	O
the	O
software	O
for	O
personal	O
use	O
,	O
educational	O
use	O
,	O
or	O
evaluation	O
,	O
free	O
of	O
charge	O
.	O
</s>
<s>
Since	O
VirtualBox	B-Operating_System
version	O
5.1.30	O
Oracle	B-Application
defines	O
personal	O
use	O
as	O
the	O
installation	O
of	O
the	O
software	O
on	O
a	O
single	O
host	O
computer	O
for	O
non-commercial	O
purposes	O
.	O
</s>
<s>
Unlike	O
some	O
software	O
using	O
a	O
proprietary	B-Application
license	I-Application
,	O
the	O
"	O
VirtualBox	B-Operating_System
Oracle	B-Operating_System
VM	I-Operating_System
VirtualBox	I-Operating_System
extension	O
pack	O
"	O
is	O
not	O
source-available	B-License
since	O
it	O
includes	O
closed-source	B-Application
components	O
,	O
which	O
does	O
not	O
make	O
the	O
source	O
code	O
publicly	O
available	O
.	O
</s>
<s>
Prior	O
to	O
version	O
4	O
,	O
there	O
were	O
two	O
different	O
packages	O
of	O
the	O
VirtualBox	B-Operating_System
software	O
.	O
</s>
<s>
The	O
full	O
package	O
was	O
offered	O
gratis	B-License
under	O
the	O
PUEL	O
,	O
with	O
licenses	O
for	O
other	O
commercial	O
deployment	O
purchasable	O
from	O
Oracle	B-Application
.	O
</s>
<s>
A	O
second	O
package	O
called	O
the	O
VirtualBox	B-Operating_System
Open	O
Source	O
Edition	O
(	O
OSE	O
)	O
was	O
released	O
under	O
GPLv2	O
.	O
</s>
<s>
This	O
removed	O
the	O
same	O
proprietary	B-Application
components	O
not	O
available	O
under	O
GPLv2	O
.	O
</s>
<s>
Building	O
the	O
BIOS	B-Operating_System
for	O
VirtualBox	B-Operating_System
requires	O
the	O
use	O
of	O
the	O
Open	B-Application
Watcom	I-Application
compiler	O
,	O
for	O
which	O
the	O
Sybase	O
Open	B-Application
Watcom	I-Application
Public	O
License	O
is	O
approved	O
as	O
"	O
Open	O
Source	O
"	O
by	O
the	O
Open	O
Source	O
Initiative	O
but	O
not	O
as	O
"	O
free	O
"	O
by	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
or	O
under	O
the	O
Debian	B-License
Free	I-License
Software	I-License
Guidelines	I-License
.	O
</s>
<s>
Although	O
VirtualBox	B-Operating_System
has	O
experimental	O
support	O
for	O
macOS	B-Application
guests	O
,	O
the	O
end	O
user	O
license	O
agreement	O
of	O
macOS	B-Application
does	O
not	O
permit	O
the	O
operating	O
system	O
to	O
run	O
on	O
non-Apple	O
hardware	O
,	O
and	O
this	O
is	O
enforced	O
within	O
the	O
operating	O
system	O
by	O
calls	O
to	O
the	O
Apple	O
System	B-Device
Management	I-Device
Controller	I-Device
(	O
SMC	O
)	O
in	O
all	O
Apple	O
machines	O
,	O
which	O
verifies	O
the	O
authenticity	O
of	O
the	O
hardware	O
.	O
</s>
<s>
Users	O
of	O
VirtualBox	B-Operating_System
can	O
load	O
multiple	O
guest	O
OSes	O
under	O
a	O
single	O
host	O
operating-system	O
(	O
host	O
OS	O
)	O
.	O
</s>
<s>
Each	O
guest	O
can	O
be	O
started	O
,	O
paused	O
and	O
stopped	O
independently	O
within	O
its	O
own	O
virtual	B-Architecture
machine	I-Architecture
(	O
VM	B-Architecture
)	O
.	O
</s>
<s>
The	O
user	O
can	O
independently	O
configure	O
each	O
VM	B-Architecture
and	O
run	O
it	O
under	O
a	O
choice	O
of	O
software-based	O
virtualization	O
or	O
hardware	O
assisted	O
virtualization	O
if	O
the	O
underlying	O
host	O
hardware	O
supports	O
this	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
supports	O
both	O
Intel	O
's	O
VT-x	O
and	O
AMD	O
's	O
AMD-V	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
.	O
</s>
<s>
Making	O
use	O
of	O
these	O
facilities	O
,	O
VirtualBox	B-Operating_System
can	O
run	O
each	O
guest	O
VM	B-Architecture
in	O
its	O
own	O
separate	O
address-space	O
;	O
the	O
guest	O
OS	O
ring	B-Operating_System
0	I-Operating_System
code	O
runs	O
on	O
the	O
host	O
at	O
ring	B-Operating_System
0	I-Operating_System
in	O
VMX	O
non-root	O
mode	O
rather	O
than	O
in	O
ring1	O
.	O
</s>
<s>
Starting	O
with	O
version	O
6.1	O
,	O
VirtualBox	B-Operating_System
only	O
supports	O
this	O
method	O
.	O
</s>
<s>
Until	O
then	O
,	O
VirtualBox	B-Operating_System
specifically	O
supported	O
some	O
guests	O
(	O
including	O
64-bit	O
guests	O
,	O
SMP	B-Operating_System
guests	O
and	O
certain	O
proprietary	B-Application
OSs	O
)	O
only	O
on	O
hosts	O
with	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
.	O
</s>
<s>
VirtualBox	B-Operating_System
emulates	O
hard	O
disks	O
in	O
three	O
formats	O
:	O
the	O
native	O
VDI	O
(	O
Virtual	O
Disk	B-Application
Image	I-Application
)	O
,	O
the	O
VMDK	O
of	O
VMware	O
and	O
the	O
VHD	O
of	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
It	O
thus	O
supports	O
disks	O
created	O
by	O
other	O
hypervisor	B-Operating_System
software	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
can	O
also	O
connect	O
to	O
iSCSI	B-Protocol
targets	O
and	O
to	O
raw	O
partitions	O
on	O
the	O
host	O
,	O
using	O
either	O
as	O
virtual	O
hard	O
disks	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
emulates	O
IDE	B-Protocol
(	O
PIIX4	O
and	O
ICH6	O
controllers	O
)	O
,	O
SCSI	B-Architecture
,	O
SATA	O
(	O
ICH8M	O
controller	O
)	O
and	O
SAS	O
controllers	O
to	O
which	O
hard	O
drives	O
can	O
be	O
attached	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
has	O
supported	O
Open	O
Virtualization	O
Format	O
(	O
OVF	O
)	O
since	O
version	O
2.2.0	O
(	O
April	O
2009	O
)	O
.	O
</s>
<s>
Both	O
ISO	B-General_Concept
images	I-General_Concept
and	O
physical	O
devices	O
connected	O
to	O
the	O
host	O
can	O
be	O
mounted	O
as	O
CD	O
or	O
DVD	O
drives	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
supports	O
running	O
operating	O
systems	O
from	O
live	O
CDs	O
and	O
DVDs	O
.	O
</s>
<s>
By	O
default	O
,	O
VirtualBox	B-Operating_System
provides	O
graphics	O
support	O
through	O
a	O
custom	O
virtual	O
graphics-card	O
that	O
is	O
VBE	B-Device
or	O
UEFI	B-Architecture
GOP	O
compatible	O
.	O
</s>
<s>
or	O
desktop	O
composition	O
via	O
virtualized	O
WDDM	B-Device
drivers	O
.	O
</s>
<s>
For	O
an	O
Ethernet	O
network	B-Protocol
adapter	I-Protocol
,	O
VirtualBox	B-Operating_System
virtualizes	O
these	O
Network	B-Protocol
Interface	I-Protocol
Cards	I-Protocol
:	O
</s>
<s>
The	O
emulated	O
network	B-Protocol
cards	I-Protocol
allow	O
most	O
guest	O
OSs	O
to	O
run	O
without	O
the	O
need	O
to	O
find	O
and	O
install	O
drivers	O
for	O
networking	O
hardware	O
as	O
they	O
are	O
shipped	O
as	O
part	O
of	O
the	O
guest	O
OS	O
.	O
</s>
<s>
A	O
special	O
paravirtualized	O
network	B-Protocol
adapter	I-Protocol
is	O
also	O
available	O
,	O
which	O
improves	O
network	O
performance	O
by	O
eliminating	O
the	O
need	O
to	O
match	O
a	O
specific	O
hardware	O
interface	O
,	O
but	O
requires	O
special	O
driver	O
support	O
in	O
the	O
guest	O
.	O
</s>
<s>
(	O
Many	O
distributions	O
of	O
Linux	B-Application
ship	O
with	O
this	O
driver	O
included	O
.	O
)	O
</s>
<s>
By	O
default	O
,	O
VirtualBox	B-Operating_System
uses	O
NAT	B-Protocol
through	O
which	O
Internet	O
software	O
for	O
end-users	O
such	O
as	O
Firefox	B-Application
or	O
ssh	B-Protocol
can	O
operate	O
.	O
</s>
<s>
Bridged	B-Protocol
networking	I-Protocol
via	O
a	O
host	O
network	B-Protocol
adapter	I-Protocol
or	O
virtual	O
networks	O
between	O
guests	O
can	O
also	O
be	O
configured	O
.	O
</s>
<s>
Up	O
to	O
36	O
network	B-Protocol
adapters	I-Protocol
can	O
be	O
attached	O
simultaneously	O
,	O
but	O
only	O
four	O
are	O
configurable	O
through	O
the	O
graphical	B-Application
interface	I-Application
.	O
</s>
<s>
For	O
a	O
sound	O
card	O
,	O
VirtualBox	B-Operating_System
virtualizes	O
Intel	O
HD	O
Audio	O
,	O
Intel	O
ICH	O
AC'97	O
and	O
SoundBlaster	B-Device
16	I-Device
devices	O
.	O
</s>
<s>
A	O
USB	B-Protocol
1.1	O
controller	O
is	O
emulated	O
so	O
that	O
any	O
USB	B-Protocol
devices	I-Protocol
attached	O
to	O
the	O
host	O
can	O
be	O
seen	O
in	O
the	O
guest	O
.	O
</s>
<s>
The	O
proprietary	B-Application
extension	O
pack	O
adds	O
a	O
USB	B-Protocol
2.0	O
or	O
USB	B-Protocol
3.0	O
controllers	O
and	O
,	O
if	O
VirtualBox	B-Operating_System
acts	O
as	O
an	O
RDP	B-Protocol
server	O
,	O
it	O
can	O
also	O
use	O
USB	B-Protocol
devices	I-Protocol
on	O
the	O
remote	O
RDP	B-Protocol
client	O
as	O
if	O
they	O
were	O
connected	O
to	O
the	O
host	O
,	O
although	O
only	O
if	O
the	O
client	O
supports	O
this	O
VirtualBox-specific	O
extension	O
(	O
Oracle	B-Application
provides	O
clients	O
for	O
Solaris	B-Application
,	O
Linux	B-Application
and	O
Sun	B-Protocol
Ray	I-Protocol
thin	O
clients	O
that	O
can	O
do	O
this	O
,	O
and	O
have	O
promised	O
support	O
for	O
other	O
platforms	O
in	O
future	O
versions	O
)	O
.	O
</s>
<s>
In	O
the	O
absence	O
of	O
hardware-assisted	B-General_Concept
virtualization	I-General_Concept
,	O
versions	O
6.0	O
and	O
earlier	O
of	O
VirtualBox	B-Operating_System
could	O
adopt	O
a	O
standard	O
software-based	O
virtualization	O
approach	O
.	O
</s>
<s>
This	O
mode	O
supports	O
32-bit	O
guest	O
OSs	O
which	O
run	O
in	O
rings	O
0	O
and	O
3	O
of	O
the	O
Intel	O
ring	B-Operating_System
architecture	O
.	O
</s>
<s>
The	O
system	O
reconfigures	O
the	O
guest	O
OS	O
code	O
,	O
which	O
would	O
normally	O
run	O
in	O
ring	B-Operating_System
0	I-Operating_System
,	O
to	O
execute	O
in	O
ring	B-Operating_System
1	I-Operating_System
on	O
the	O
host	O
hardware	O
.	O
</s>
<s>
Because	O
this	O
code	O
contains	O
many	O
privileged	O
instructions	O
which	O
cannot	O
run	O
natively	O
in	O
ring	B-Operating_System
1	I-Operating_System
,	O
VirtualBox	B-Operating_System
employs	O
a	O
Code	O
Scanning	O
and	O
Analysis	O
Manager	O
(	O
CSAM	O
)	O
to	O
scan	O
the	O
ring	B-Operating_System
0	I-Operating_System
code	O
recursively	O
before	O
its	O
first	O
execution	O
to	O
identify	O
problematic	O
instructions	O
and	O
then	O
calls	O
the	O
Patch	O
Manager	O
(	O
PATM	O
)	O
to	O
perform	O
in-situ	O
patching	O
.	O
</s>
<s>
This	O
replaces	O
the	O
instruction	O
with	O
a	O
jump	O
to	O
a	O
VM-safe	O
equivalent	O
compiled	O
code	O
fragment	O
in	O
hypervisor	B-Operating_System
memory	O
.	O
</s>
<s>
The	O
guest	O
user-mode	B-Operating_System
code	O
,	O
running	O
in	O
ring	B-Operating_System
3	I-Operating_System
,	O
generally	O
runs	O
directly	O
on	O
the	O
host	O
hardware	O
in	O
ring	B-Operating_System
3	I-Operating_System
.	O
</s>
<s>
In	O
both	O
cases	O
,	O
VirtualBox	B-Operating_System
uses	O
CSAM	O
and	O
PATM	O
to	O
inspect	O
and	O
patch	O
the	O
offending	O
instructions	O
whenever	O
a	O
fault	O
occurs	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
also	O
contains	O
a	O
dynamic	O
recompiler	O
,	O
based	O
on	O
QEMU	B-Application
to	O
recompile	O
any	O
real	B-Application
mode	I-Application
or	O
protected	B-Application
mode	I-Application
code	O
entirely	O
(	O
e.g.	O
</s>
<s>
BIOS	B-Operating_System
code	O
,	O
a	O
DOS	O
guest	O
,	O
or	O
any	O
operating	O
system	O
startup	O
)	O
.	O
</s>
<s>
Using	O
these	O
techniques	O
,	O
VirtualBox	B-Operating_System
can	O
achieve	O
a	O
performance	O
comparable	O
to	O
that	O
of	O
VMware	O
.	O
</s>
<s>
The	O
feature	O
was	O
dropped	O
starting	O
with	O
VirtualBox	B-Operating_System
6.1	O
.	O
</s>
<s>
"	O
Host	O
key	O
"	O
for	O
releasing	O
the	O
keyboard	O
and	O
mouse	O
cursor	O
to	O
the	O
host	O
system	O
if	O
captured	O
(	O
coupled	O
)	O
to	O
the	O
guest	O
system	O
,	O
and	O
for	O
keyboard	O
shortcuts	O
to	O
features	O
such	O
as	O
configuration	O
,	O
restarting	O
,	O
and	O
screenshot	B-Application
.	O
</s>
<s>
Ability	O
to	O
mount	O
virtual	B-Application
hard	I-Application
disk	I-Application
drives	I-Application
and	O
disk	B-Application
images	I-Application
.	O
</s>
<s>
Virtual	O
optical	B-General_Concept
disc	I-General_Concept
images	I-General_Concept
can	O
be	O
used	O
for	O
booting	O
and	O
sharing	O
files	O
to	O
guest	O
systems	O
lacking	O
networking	O
support	O
.	O
</s>
<s>
3D	O
graphics	O
acceleration	O
for	O
Windows	B-Application
guests	O
earlier	O
than	O
Windows	B-Application
7	O
was	O
removed	O
in	O
version	O
6.1	O
.	O
</s>
<s>
This	O
affected	O
Windows	B-Application
XP	I-Application
and	O
Windows	B-Application
Vista	I-Application
.	O
</s>
<s>
VirtualBox	B-Operating_System
has	O
a	O
very	O
low	O
transfer	O
rate	O
to	O
and	O
from	O
USB2	O
devices	O
.	O
</s>
<s>
Despite	O
being	O
an	O
open	O
source	O
product	O
,	O
some	O
of	O
its	O
features	O
are	O
available	O
only	O
in	O
a	O
binary	O
form	O
under	O
a	O
commercial	O
license	O
(	O
see	O
"	O
VirtualBox	B-Operating_System
Extension	O
Pack	O
"	O
below	O
)	O
.	O
</s>
<s>
USB3	O
devices	O
pass	O
through	O
is	O
not	O
supported	O
by	O
older	O
guest	O
OSes	O
like	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Application
XP	I-Application
due	O
to	O
the	O
lack	O
of	O
drivers	O
however	O
starting	O
with	O
version	O
5.0	O
VirtualBox	B-Operating_System
offers	O
experimental	O
Renesas	O
uPD720201	O
xHCI	O
USB3	O
controller	O
which	O
allows	O
to	O
use	O
USB3	O
in	O
these	O
operating	O
systems	O
through	O
manual	O
modification	O
of	O
configuration	B-Protocol
files	I-Protocol
.	O
</s>
<s>
Guest	B-Operating_System
Additions	I-Operating_System
for	O
macOS	B-Application
are	O
unavailable	O
at	O
this	O
time	O
.	O
</s>
<s>
Guest	B-Operating_System
Additions	I-Operating_System
for	O
Windows	B-Application
9x	O
(	O
Windows	B-Application
95	I-Application
,	O
98	B-Device
and	O
ME	B-Device
)	O
are	O
not	O
available	O
.	O
</s>
<s>
This	O
results	O
in	O
poor	O
performance	O
due	O
to	O
the	O
lack	O
of	O
graphics	O
acceleration	O
with	O
the	O
default	O
limited	O
color	O
depth	O
(	O
external	O
third-party	B-General_Concept
software	I-General_Concept
is	O
available	O
to	O
enable	O
support	O
for	O
32-bit	O
color	O
mode	O
,	O
resulting	O
in	O
better	O
performance	O
)	O
.	O
</s>
<s>
EFI	B-Architecture
support	O
is	O
incomplete	O
,	O
e.g.	O
</s>
<s>
EFI	B-Architecture
boot	O
for	O
a	O
Windows	B-Application
7	O
guest	O
is	O
not	O
supported	O
.	O
</s>
<s>
Only	O
older	O
versions	O
of	O
DirectX	B-Application
and	O
OpenGL	B-Application
passthrough	O
are	O
supported	O
(	O
the	O
feature	O
can	O
be	O
enabled	O
using	O
the	O
3D	O
Acceleration	O
option	O
for	O
each	O
VM	B-Architecture
individually	O
)	O
.	O
</s>
<s>
Video	O
RAM	O
is	O
limited	O
to	O
128	O
MiB	O
(	O
256	O
MiB	O
with	O
2D	O
Video	O
Acceleration	O
enabled	O
)	O
due	O
to	O
technical	O
difficulties	O
(	O
merely	O
changing	O
the	O
GUI	B-Application
to	O
allow	O
the	O
user	O
to	O
allocate	O
more	O
video	O
RAM	O
to	O
a	O
VM	B-Architecture
or	O
manually	O
editing	O
the	O
configuration	B-Protocol
file	I-Protocol
of	O
a	O
VM	B-Architecture
wo	O
n't	O
work	O
and	O
will	O
result	O
in	O
a	O
fatal	B-Error_Name
error	I-Error_Name
)	O
.	O
</s>
<s>
Windows	O
95/98/98SE/ME	O
cannot	O
be	O
installed	O
or	O
work	O
unreliably	O
with	O
modern	O
CPUs	O
(	O
AMD	O
Zen	O
and	O
newer	O
;	O
Intel	B-Device
Tiger	I-Device
Lake	I-Device
and	O
newer	O
)	O
and	O
hardware	O
assisted	O
virtualization	O
(	O
VirtualBox	B-Operating_System
6.1	O
and	O
higher	O
)	O
.	O
</s>
<s>
An	O
open	O
source	O
patch	O
has	O
been	O
developed	O
to	O
fix	O
the	O
issue	O
which	O
also	O
addresses	O
Windows	O
95/98/98SE	O
bug	O
which	O
makes	O
the	O
system	O
crash	O
when	O
running	O
on	O
new	O
fast	O
CPUs	O
.	O
</s>
<s>
VirtualBox	B-Operating_System
7.0	O
and	O
later	O
is	O
required	O
to	O
run	O
a	O
pristine	O
Windows	B-Application
11	I-Application
guest	O
.	O
</s>
<s>
Windows	B-Device
8.1	I-Device
and	O
higher	O
.	O
</s>
<s>
Support	O
for	O
64-bit	O
Windows	B-Application
was	O
added	O
with	O
VirtualBox	B-Operating_System
1.5	O
.	O
</s>
<s>
Support	O
for	O
Windows	B-Application
XP	I-Application
was	O
removed	O
with	O
VirtualBox	B-Operating_System
5.0	O
.	O
</s>
<s>
Support	O
for	O
Windows	B-Application
Vista	I-Application
was	O
removed	O
with	O
VirtualBox	B-Operating_System
5.2	O
.	O
</s>
<s>
Windows	B-Application
7	O
support	O
was	O
removed	O
in	O
version	O
6.1	O
.	O
</s>
<s>
macOS	B-Application
from	O
version	O
10.13	B-Operating_System
High	I-Operating_System
Sierra	I-Operating_System
to	O
10.15	B-Device
Catalina	I-Device
(	O
only	O
on	O
Intel-based	B-Device
Macs	I-Device
)	O
:	O
</s>
<s>
Preliminary	O
Mac	B-Application
OS	I-Application
X	O
support	O
(	O
beta	O
stage	O
)	O
was	O
added	O
with	O
VirtualBox	B-Operating_System
1.4	O
,	O
full	O
support	O
with	O
1.6	O
.	O
</s>
<s>
Mac	B-Application
OS	I-Application
X	O
10.4	O
(	O
Tiger	O
)	O
support	O
was	O
removed	O
with	O
VirtualBox	B-Operating_System
3.1	O
.	O
</s>
<s>
Support	O
for	O
Mac	B-Application
OS	I-Application
X	O
10.7	O
(	O
Lion	O
)	O
and	O
earlier	O
was	O
removed	O
with	O
VirtualBox	B-Operating_System
5.0	O
.	O
</s>
<s>
Support	O
for	O
Mac	B-Application
OS	I-Application
X	O
10.8	O
(	O
Mountain	O
Lion	O
)	O
was	O
removed	O
with	O
VirtualBox	B-Operating_System
5.1	O
.	O
</s>
<s>
Support	O
for	O
Mac	B-Application
OS	I-Application
X	O
10.9	O
(	O
Mavericks	O
)	O
was	O
removed	O
with	O
VirtualBox	B-Operating_System
5.2	O
.	O
</s>
<s>
Support	O
for	O
(	O
Mac	O
)	O
OS	O
X	O
10.10	O
Yosemite	O
and	O
OS	O
X	O
10.11	O
El	O
Capitan	O
was	O
removed	O
with	O
VirtualBox	B-Operating_System
6.0	O
.	O
</s>
<s>
No	O
support	O
of	O
macOS	B-Operating_System
11	I-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
and	O
later	O
versions	O
is	O
officially	O
provided	O
.	O
</s>
<s>
Users	O
reported	O
various	O
technical	O
issues	O
when	O
running	O
VirtualBox	B-Operating_System
on	O
macOS	B-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
.	O
</s>
<s>
Experimental	O
support	O
for	O
Apple	B-Device
silicon-based	I-Device
Macs	I-Device
was	O
added	O
in	O
version	O
7.0	O
beta	O
.	O
</s>
<s>
Some	O
features	O
require	O
the	O
installation	O
of	O
the	O
closed-source	B-Application
"	O
VirtualBox	B-Operating_System
Extension	O
Pack	O
"	O
:	O
</s>
<s>
VirtualBox	B-Operating_System
RDP	B-Protocol
:	O
support	O
for	O
the	O
proprietary	B-Application
remote	O
connection	O
protocol	O
developed	O
by	O
Microsoft	O
and	O
Citrix	B-Application
Systems	I-Application
.	O
</s>
<s>
PXE	B-Device
boot	O
for	O
Intel	O
cards	O
.	O
</s>
<s>
While	O
VirtualBox	B-Operating_System
itself	O
is	O
free	O
to	O
use	O
and	O
is	O
distributed	O
under	O
an	O
open	O
source	O
license	O
the	O
VirtualBox	B-Operating_System
Extension	O
Pack	O
is	O
licensed	O
under	O
the	O
VirtualBox	B-Operating_System
Personal	O
Use	O
and	O
Evaluation	O
License	O
(	O
PUEL	O
)	O
.	O
</s>
<s>
Oracle	B-Application
routinely	O
checks	O
log	O
files	O
for	O
downloads	O
of	O
the	O
VirtualBox	B-Operating_System
Extension	O
Pack	O
from	O
nonresidential	O
IP	O
addresses	O
and	O
contacts	O
unlicensed	O
users	O
to	O
enforce	O
compliance	O
.	O
</s>
<s>
While	O
Guest	B-Operating_System
Additions	I-Operating_System
are	O
installed	O
within	O
each	O
suitable	O
guest	O
virtual	B-Architecture
machine	I-Architecture
,	O
the	O
Extension	O
Pack	O
is	O
installed	O
on	O
the	O
host	O
running	O
VirtualBox	B-Operating_System
.	O
</s>
<s>
A	O
commercial	O
port	O
of	O
VirtualBox	B-Operating_System
OSE	I-Operating_System
with	O
built-in	O
support	O
for	O
Direct	B-Application
X	I-Application
12.1	O
/	O
Vulkan	O
3D	O
API	O
inside	O
virtual	B-Architecture
machines	I-Architecture
has	O
been	O
released	O
by	O
the	O
main	O
contributor	O
of	O
the	O
FreeRDP	O
project	O
,	O
called	O
Thincast	O
Workstation	O
.	O
</s>
