<s>
MAME	B-Device
(	O
formerly	O
an	O
acronym	O
of	O
Multiple	B-Device
Arcade	I-Device
Machine	I-Device
Emulator	I-Device
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
emulator	B-Application
designed	O
to	O
recreate	O
the	O
hardware	O
of	O
arcade	O
game	O
systems	O
in	O
software	O
on	O
modern	O
personal	O
computers	O
and	O
other	O
platforms	O
.	O
</s>
<s>
It	O
does	O
this	O
by	O
emulating	B-Application
the	O
inner	O
workings	O
of	O
the	O
emulated	B-Application
arcade	O
machines	O
;	O
the	O
ability	O
to	O
actually	O
play	O
the	O
games	O
is	O
considered	O
"	O
a	O
nice	O
side	O
effect	O
"	O
.	O
</s>
<s>
Joystiq	O
has	O
listed	O
MAME	B-Device
as	O
an	O
application	O
that	O
every	O
Windows	B-Application
and	O
Mac	B-Application
gamer	O
should	O
have	O
.	O
</s>
<s>
The	O
first	O
public	O
MAME	B-Device
release	O
was	O
by	O
Nicola	O
Salmoria	O
on	O
5	O
February	O
1997	O
.	O
</s>
<s>
It	O
now	O
supports	O
over	O
7,000	O
unique	O
games	O
and	O
10,000	O
actual	O
ROM	B-General_Concept
image	I-General_Concept
sets	O
,	O
though	O
not	O
all	O
of	O
the	O
games	O
are	O
playable	O
.	O
</s>
<s>
MESS	B-Application
,	O
an	O
emulator	B-Application
for	O
many	O
video	B-Device
game	I-Device
consoles	I-Device
and	O
computer	O
systems	O
,	O
based	O
on	O
the	O
MAME	B-Device
core	O
,	O
was	O
integrated	O
into	O
MAME	B-Device
in	O
2015	O
.	O
</s>
<s>
With	O
OTVDM	O
(	O
WineVDM	O
)	O
a	O
version	O
of	O
MAME	B-Device
is	O
available	O
to	O
emulate	O
16-Bit	B-Device
DOS	B-Device
and	O
Windows	B-Application
applications	O
on	O
x64	B-Application
and	O
AArch64	B-Architecture
versions	O
of	O
Windows	B-Application
.	O
</s>
<s>
The	O
NTVDM	O
from	O
Microsoft	O
is	O
only	O
supported	O
for	O
the	O
32-bit	O
versions	O
of	O
Windows	B-Application
.	O
</s>
<s>
The	O
MAME	B-Device
project	O
was	O
started	O
by	O
Italian	O
programmer	O
Nicola	O
Salmoria	O
.	O
</s>
<s>
It	O
began	O
as	O
a	O
project	O
called	O
Multi-Pac	O
,	O
intended	O
to	O
preserve	O
games	O
in	O
the	O
Pac-Man	B-Application
family	O
,	O
but	O
the	O
name	O
was	O
changed	O
as	O
more	O
games	O
were	O
added	O
to	O
its	O
framework	O
.	O
</s>
<s>
The	O
first	O
MAME	B-Device
version	O
was	O
released	O
in	O
1996	O
.	O
</s>
<s>
In	O
May	O
2003	O
,	O
David	O
Haywood	O
took	O
over	O
as	O
project	O
coordinator	O
;	O
and	O
from	O
April	O
2005	O
to	O
April	O
2011	O
,	O
the	O
project	O
was	O
coordinated	O
by	O
Aaron	B-Device
Giles	I-Device
;	O
then	O
Angelo	O
Salese	O
stepped	O
in	O
as	O
the	O
coordinator	O
;	O
and	O
in	O
2012	O
,	O
Miodrag	O
Milanovic	O
took	O
over	O
.	O
</s>
<s>
At	O
first	O
,	O
MAME	B-Device
was	O
developed	O
exclusively	O
for	O
MS-DOS	B-Application
,	O
but	O
was	O
soon	O
ported	O
to	O
Unix-like	B-Operating_System
systems	I-Operating_System
(	O
X/MAME	O
)	O
,	O
Macintosh	O
(	O
MacMAME	B-Device
and	O
later	O
MAME	B-Device
OS	O
X	O
)	O
and	O
Windows	B-Application
(	O
MAME32	B-Device
)	O
.	O
</s>
<s>
Since	O
24	O
May	O
2001	O
,	O
with	O
version	O
0.37b15	O
,	O
MAME	B-Device
's	O
main	O
development	O
has	O
occurred	O
on	O
the	O
Windows	B-Application
platform	O
,	O
and	O
most	O
other	O
platforms	O
are	O
supported	O
through	O
the	O
SDLMAME	B-Operating_System
project	O
,	O
which	O
was	O
integrated	O
into	O
the	O
main	O
development	O
source	O
tree	O
in	O
2006	O
.	O
</s>
<s>
MAME	B-Device
has	O
also	O
been	O
ported	O
to	O
other	O
computers	O
,	O
game	O
consoles	O
,	O
mobile	O
phones	O
and	O
PDAs	O
,	O
and	O
at	O
one	O
point	O
even	O
to	O
digital	O
cameras	O
.	O
</s>
<s>
In	O
2012	O
,	O
Google	B-Application
ported	O
MAME	B-Device
to	O
Native	B-Application
Client	I-Application
,	O
which	O
allows	O
MAME	B-Device
to	O
run	O
inside	O
Chrome	B-Application
.	O
</s>
<s>
Major	O
releases	O
of	O
MAME	B-Device
occur	O
approximately	O
once	O
a	O
month	O
.	O
</s>
<s>
Windows	B-Application
executables	O
in	O
both	O
32-bit	O
and	O
64-bit	O
fashion	O
are	O
released	O
on	O
the	O
,	O
along	O
with	O
the	O
complete	O
source	O
code	O
.	O
</s>
<s>
Smaller	O
,	O
incremental	O
"	O
u	O
"	O
(	O
for	O
update	O
)	O
releases	O
were	O
released	O
weekly	O
(	O
until	O
version	O
0.149u1	O
)	O
as	O
source	O
diffs	B-Application
against	O
the	O
most	O
recent	O
major	O
version	O
,	O
to	O
keep	O
code	O
in	O
synchronization	O
among	O
developers	O
.	O
</s>
<s>
MAME	B-Device
's	O
source	O
code	O
is	O
developed	O
on	O
a	O
public	O
GitHub	B-Application
repository	O
,	O
allowing	O
those	O
with	O
the	O
required	O
expertise	O
and	O
tools	O
to	O
build	O
the	O
most	O
up-to-date	O
version	O
and	O
contribute	O
enhancements	O
as	O
pull	O
requests	O
.	O
</s>
<s>
Historical	O
version	O
numbers	O
0.32	O
,	O
and	O
0.38	O
through	O
0.52	O
inclusively	O
,	O
do	O
not	O
exist	O
;	O
the	O
former	O
was	O
skipped	O
due	O
to	O
similar	O
naming	O
of	O
the	O
GUI-equipped	O
MAME32	B-Device
variant	O
(	O
which	O
itself	O
has	O
since	O
been	O
renamed	O
due	O
to	O
the	O
move	O
to	O
64-bit	O
builds	O
)	O
,	O
while	O
the	O
latter	O
numbers	O
were	O
skipped	O
due	O
to	O
the	O
numerous	O
releases	O
in	O
the	O
0.37	O
beta	O
cycle	O
(	O
these	O
version	O
numbers	O
have	O
since	O
been	O
marked	O
next	O
to	O
their	O
equivalent	O
0.37	O
beta	O
releases	O
on	O
the	O
official	O
MAMEdev	O
website	O
)	O
.	O
</s>
<s>
MAME	B-Device
's	O
architecture	O
has	O
been	O
extensively	O
improved	O
over	O
the	O
years	O
.	O
</s>
<s>
Support	O
for	O
both	O
raster	B-Algorithm
and	O
vector	B-General_Concept
displays	I-General_Concept
,	O
multiple	O
CPUs	O
,	O
and	O
sound	O
chips	O
were	O
added	O
in	O
the	O
project	O
's	O
first	O
six	O
months	O
.	O
</s>
<s>
A	O
flexible	O
timer	O
system	O
to	O
coordinate	O
synchronization	O
between	O
multiple	O
emulated	B-Application
CPU	O
cores	O
was	O
implemented	O
,	O
and	O
ROM	B-General_Concept
images	I-General_Concept
started	O
to	O
be	O
loaded	O
according	O
to	O
their	O
CRC32	O
hash	O
in	O
the	O
ZIP	B-General_Concept
files	I-General_Concept
they	O
were	O
stored	O
in	O
.	O
</s>
<s>
MAME	B-Device
has	O
pioneered	O
the	O
reverse	O
engineering	O
of	O
many	O
undocumented	O
system	O
architectures	O
,	O
various	O
CPUs	O
(	O
such	O
as	O
the	O
M6809-derivative	O
custom	O
Konami	O
CPU	O
with	O
new	O
instructions	O
)	O
and	O
sound	O
chips	O
(	O
for	O
example	O
,	O
Yamaha	O
FM	O
sound	O
chips	O
)	O
.	O
</s>
<s>
MAME	B-Device
developers	O
have	O
been	O
instrumental	O
in	O
reverse	O
engineering	O
many	O
proprietary	O
encryption	O
algorithms	O
utilized	O
in	O
arcade	O
games	O
,	O
including	O
Neo	B-Application
Geo	I-Application
,	O
CP	B-Application
System	I-Application
II	I-Application
and	O
CP	B-Application
System	I-Application
III	I-Application
.	O
</s>
<s>
MAME	B-Device
's	O
popularity	O
has	O
gone	O
mainstream	O
,	O
with	O
enthusiasts	O
building	O
their	O
own	O
arcade	O
game	O
cabinets	O
to	O
replay	O
old	O
games	O
,	O
and	O
even	O
with	O
some	O
companies	O
producing	O
illegal	O
MAME	B-Device
derivatives	O
to	O
be	O
installed	O
in	O
arcades	O
.	O
</s>
<s>
Cabinets	O
inspired	O
by	O
classic	O
games	O
can	O
also	O
be	O
purchased	O
and	O
assembled	O
(	O
with	O
MAME	B-Device
optionally	O
preinstalled	O
)	O
.	O
</s>
<s>
Although	O
MAME	B-Device
contains	O
a	O
rudimentary	O
user	O
interface	O
,	O
the	O
use	O
of	O
MAME	B-Device
in	O
arcade	O
game	O
cabinets	O
and	O
home	O
theaters	O
necessitates	O
special	O
launcher	O
applications	O
called	O
front	B-Architecture
ends	I-Architecture
with	O
more	O
advanced	O
features	O
.	O
</s>
<s>
The	O
information	O
within	O
MAME	B-Device
is	O
free	O
for	O
reuse	O
,	O
and	O
companies	O
have	O
been	O
known	O
to	O
utilize	O
MAME	B-Device
when	O
recreating	O
their	O
old	O
classics	O
on	O
modern	O
systems	O
.	O
</s>
<s>
Some	O
have	O
even	O
hired	O
MAME	B-Device
developers	O
to	O
create	O
emulators	B-Application
for	O
their	O
old	O
properties	O
.	O
</s>
<s>
An	O
example	O
is	O
the	O
Taito	O
Legends	O
pack	O
,	O
with	O
ROMs	O
readable	O
on	O
select	O
versions	O
of	O
MAME	B-Device
.	O
</s>
<s>
On	O
27	O
May	O
2015	O
(	O
0.162	O
)	O
,	O
the	O
games	O
console	O
and	O
computer	O
system	O
emulator	B-Application
MESS	B-Application
was	O
integrated	O
with	O
MAME	B-Device
(	O
so	O
the	O
MESS	B-Application
User	O
Manual	O
is	O
still	O
the	O
most	O
important	O
usage	O
instruction	O
for	O
the	O
non-arcade	O
parts	O
of	O
MAME	B-Device
)	O
.	O
</s>
<s>
This	O
also	O
lead	O
to	O
the	O
removal	O
of	O
the	O
acronym	O
,	O
as	O
MAME	B-Device
can	O
now	O
emulate	O
more	O
than	O
arcade	O
machines	O
.	O
</s>
<s>
Since	O
2012	O
,	O
MAME	B-Device
has	O
been	O
maintained	O
by	O
former	O
MESS	B-Application
project	O
leader	O
Miodrag	O
Milanović	O
.	O
</s>
<s>
In	O
May	O
2015	O
,	O
it	O
was	O
announced	O
that	O
MAME	B-Device
's	O
developers	O
planned	O
to	O
re-license	O
the	O
software	O
under	O
a	O
more	O
common	O
free	B-License
and	I-License
open-source	I-License
license	B-License
,	O
away	O
from	O
the	O
original	O
MAME	B-Device
license	B-License
.	O
</s>
<s>
MAME	B-Device
developer	O
Miodrag	O
Milanovic	O
explained	O
that	O
the	O
change	O
was	O
to	O
draw	O
more	O
developer	O
interest	O
,	O
allow	O
game	O
manufacturers	O
to	O
distribute	O
MAME	B-Device
to	O
emulate	O
their	O
own	O
games	O
,	O
and	O
to	O
make	O
the	O
software	O
"	O
a	O
learning	O
tool	O
for	O
developers	O
working	O
on	O
development	O
boards	O
"	O
.	O
</s>
<s>
The	O
transition	O
of	O
MAME	B-Device
's	O
licensing	O
to	O
BSD/GPL	B-License
was	O
completed	O
in	O
March	O
2016	O
.	O
</s>
<s>
Most	O
of	O
MAME	B-Device
's	O
source	O
code	O
(	O
90%+	O
)	O
is	O
now	O
available	O
under	O
the	O
BSD-3-Clause	B-Operating_System
license	B-License
,	O
and	O
the	O
complete	O
project	O
is	O
under	O
the	O
GPL-2.0-or-later	B-License
license	B-License
.	O
</s>
<s>
On	O
24	O
February	O
2016	O
(	O
0.171	O
)	O
,	O
MAME	B-Device
embedded	O
the	O
MEWUI	O
front-end	B-Architecture
(	O
and	O
its	O
developer	O
joined	O
the	O
team	O
)	O
,	O
providing	O
MAME	B-Device
with	O
a	O
flexible	O
and	O
more	O
full-featured	O
UI	O
.	O
</s>
<s>
On	O
30	O
December	O
2021	O
,	O
exA-Arcadia	O
,	O
the	O
Western	O
copyright	O
holders	O
of	O
the	O
games	O
Akai	B-Application
Katana	I-Application
and	O
DoDonPachi	B-Application
SaiDaiOuJou	I-Application
had	O
their	O
lawyers	O
file	O
a	O
cease	O
and	O
desist	O
notice	O
to	O
the	O
MAME	B-Device
developers	O
over	O
those	O
games	O
being	O
included	O
in	O
the	O
emulator	B-Application
.	O
</s>
<s>
MAME	B-Device
complied	O
with	O
the	O
request	O
a	O
day	O
later	O
,	O
making	O
both	O
unplayable	O
on	O
the	O
emulator	B-Application
outside	O
of	O
command	O
line	O
,	O
as	O
of	O
version	O
0.240	O
.	O
</s>
<s>
The	O
MAME	B-Device
core	O
coordinates	O
the	O
emulation	B-Application
of	O
several	O
elements	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
MAME	B-Device
can	O
emulate	O
many	O
different	O
central	B-General_Concept
processing	I-General_Concept
units	I-General_Concept
(	O
CPUs	O
)	O
and	O
associated	O
hardware	O
.	O
</s>
<s>
These	O
elements	O
are	O
virtualized	O
so	O
MAME	B-Device
acts	O
as	O
a	O
software	O
layer	O
between	O
the	O
original	O
program	O
of	O
the	O
game	O
,	O
and	O
the	O
platform	O
MAME	B-Device
runs	O
on	O
.	O
</s>
<s>
MAME	B-Device
supports	O
arbitrary	O
screen	O
resolutions	O
,	O
refresh	O
rates	O
and	O
display	O
configurations	O
.	O
</s>
<s>
Multiple	O
emulated	B-Application
monitors	O
,	O
as	O
required	O
by	O
for	O
example	O
Darius	B-Application
,	O
are	O
supported	O
as	O
well	O
.	O
</s>
<s>
Individual	O
arcade	O
systems	O
are	O
specified	O
by	O
drivers	O
which	O
take	O
the	O
form	O
of	O
C	B-Language
preprocessor	I-Language
macros	O
.	O
</s>
<s>
These	O
drivers	O
specify	O
the	O
individual	O
components	O
to	O
be	O
emulated	B-Application
and	O
how	O
they	O
communicate	O
with	O
each	O
other	O
.	O
</s>
<s>
While	O
MAME	B-Device
was	O
originally	O
written	O
in	O
C	B-Language
,	O
the	O
need	O
for	O
object	O
oriented	O
programming	O
caused	O
the	O
development	O
team	O
to	O
begin	O
to	O
compile	O
all	O
code	O
as	O
C++	B-Language
for	O
MAME	B-Device
0.136	O
,	O
taking	O
advantage	O
of	O
additional	O
features	O
of	O
that	O
language	O
in	O
the	O
process	O
.	O
</s>
<s>
Although	O
a	O
great	O
majority	O
of	O
the	O
CPU	O
emulation	B-Application
cores	O
are	O
interpretive	B-Application
,	O
MAME	B-Device
also	O
supports	O
dynamic	O
recompilation	O
through	O
an	O
intermediate	O
language	O
called	O
the	O
Universal	O
Machine	O
Language	O
(	O
UML	O
)	O
to	O
increase	O
the	O
emulation	B-Application
speed	O
.	O
</s>
<s>
Back-end	B-Architecture
targets	O
supported	O
are	O
x86	O
and	O
x64	B-Application
.	O
</s>
<s>
A	O
C	B-Language
back	B-Architecture
end	I-Architecture
is	O
also	O
available	O
to	O
further	O
aid	O
verification	O
of	O
the	O
correctness	O
.	O
</s>
<s>
CPUs	O
emulated	B-Application
in	O
this	O
manner	O
are	O
SH-2	O
,	O
MIPS	O
R3000	O
and	O
PowerPC	O
.	O
</s>
<s>
The	O
original	O
program	O
code	O
,	O
graphics	O
and	O
sound	O
data	O
need	O
to	O
be	O
present	O
so	O
that	O
the	O
system	O
can	O
be	O
emulated	B-Application
.	O
</s>
<s>
In	O
most	O
arcade	O
machines	O
,	O
the	O
data	O
is	O
stored	O
in	O
read-only	B-Device
memory	I-Device
chips	I-Device
(	O
ROMs	O
)	O
,	O
although	O
other	O
devices	O
such	O
as	O
cassette	B-Device
tapes	I-Device
,	O
floppy	B-Device
disks	I-Device
,	O
hard	B-Device
disks	I-Device
,	O
laserdiscs	O
,	O
and	O
compact	O
discs	O
are	O
also	O
used	O
.	O
</s>
<s>
The	O
resulting	O
files	O
are	O
often	O
generically	O
called	O
ROM	B-General_Concept
images	I-General_Concept
or	O
ROMs	O
regardless	O
of	O
the	O
kind	O
of	O
storage	O
they	O
came	O
from	O
.	O
</s>
<s>
A	O
game	O
usually	O
consists	O
of	O
multiple	O
ROM	B-Device
and	O
PAL	O
images	O
;	O
these	O
are	O
collectively	O
stored	O
inside	O
a	O
single	O
ZIP	B-General_Concept
file	I-General_Concept
,	O
constituting	O
a	O
"	O
ROM	B-Device
set	O
"	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
"	O
parent	O
"	O
ROM	B-Device
set	O
(	O
usually	O
chosen	O
as	O
the	O
most	O
recent	O
"	O
World	O
"	O
version	O
of	O
the	O
game	O
)	O
,	O
games	O
may	O
have	O
"	O
clone	O
"	O
ROM	B-Device
sets	O
with	O
different	O
program	O
code	O
,	O
different	O
language	O
text	O
intended	O
for	O
different	O
markets	O
etc	O
.	O
</s>
<s>
For	O
example	O
,	O
Street	B-Application
Fighter	I-Application
II	I-Application
Turbo	I-Application
is	O
considered	O
a	O
variant	O
of	O
Street	B-Application
Fighter	I-Application
II	I-Application
Champion	O
Edition	O
.	O
</s>
<s>
System	O
boards	O
like	O
the	O
Neo	B-Application
Geo	I-Application
that	O
have	O
ROMs	O
shared	O
between	O
multiple	O
games	O
require	O
the	O
ROMs	O
to	O
be	O
stored	O
in	O
"	O
BIOS	O
"	O
ROM	B-Device
sets	O
and	O
named	O
appropriately	O
.	O
</s>
<s>
MAME	B-Device
ROMs	O
come	O
in	O
three	O
forms	O
,	O
split	O
,	O
non-merged	O
,	O
and	O
merged	O
:	O
</s>
<s>
A	O
"	O
split	O
"	O
ROM	B-Device
only	O
contains	O
information	O
about	O
itself	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
"	O
clone	O
"	O
ROM	B-Device
does	O
not	O
have	O
the	O
necessary	O
data	O
the	O
"	O
parent	O
"	O
ROM	B-Device
has	O
,	O
and	O
a	O
"	O
parent	O
"	O
ROM	B-Device
will	O
not	O
contain	O
its	O
clones	O
.	O
</s>
<s>
A	O
"	O
non-merged	O
"	O
set	O
is	O
a	O
ROM	B-Device
that	O
has	O
everything	O
a	O
program	O
needs	O
to	O
run	O
in	O
one	O
ZIP	B-General_Concept
file	I-General_Concept
,	O
such	O
as	O
its	O
"	O
parent	O
"	O
.	O
</s>
<s>
A	O
"	O
merged	O
"	O
set	O
is	O
a	O
ROM	B-Device
that	O
contains	O
the	O
"	O
parent	O
"	O
ROM	B-Device
and	O
its	O
"	O
clones	O
"	O
in	O
one	O
package	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
merged	O
Pac-Man	B-Application
rom	B-Device
would	O
contain	O
the	O
"	O
parent	O
"	O
Japanese	O
Puck-Man	B-Application
rom	B-Device
,	O
the	O
Midway	O
USA	O
Pac-Man	B-Application
version	O
,	O
and	O
all	O
other	O
clone	O
or	O
bootleg	B-General_Concept
versions	O
of	O
the	O
game	O
.	O
</s>
<s>
Hard	B-Device
disks	I-Device
,	O
compact	O
discs	O
and	O
laserdiscs	O
are	O
stored	O
in	O
a	O
MAME-specific	O
format	O
called	O
CHD	O
(	O
Compressed	O
Hunks	O
of	O
Data	O
)	O
.	O
</s>
<s>
This	O
data	O
must	O
be	O
captured	O
and	O
encoded	O
into	O
digital	O
files	O
that	O
can	O
be	O
read	O
by	O
MAME	B-Device
.	O
</s>
<s>
MAME	B-Device
does	O
not	O
support	O
the	O
use	O
of	O
external	O
analog	O
devices	O
,	O
which	O
(	O
along	O
with	O
identical	O
speaker	O
and	O
speaker	O
enclosures	O
)	O
would	O
be	O
required	O
for	O
a	O
100%	O
faithful	O
reproduction	O
of	O
the	O
arcade	O
experience	O
.	O
</s>
<s>
A	O
number	O
of	O
games	O
use	O
sound	O
chips	O
that	O
have	O
not	O
yet	O
been	O
emulated	B-Application
successfully	O
.	O
</s>
<s>
These	O
games	O
require	O
sound	O
samples	O
in	O
WAV	O
file	O
format	O
for	O
sound	O
emulation	B-Application
.	O
</s>
<s>
MAME	B-Device
additionally	O
supports	O
artwork	O
files	O
in	O
PNG	O
format	O
for	O
bezel	O
and	O
overlay	O
graphics	O
.	O
</s>
<s>
Furthermore	O
,	O
emulation	B-Application
of	O
games	O
with	O
liquid-crystal	B-Device
displays	I-Device
such	O
as	O
Game	B-Device
&	I-Device
Watch	I-Device
or	O
extra	O
physical	O
aspects	O
such	O
as	O
slot	O
machines	O
usually	O
require	O
extra	O
image	O
files	O
for	O
backgrounds	O
or	O
other	O
aspects	O
of	O
the	O
games	O
.	O
</s>
<s>
The	O
stated	O
aim	O
of	O
the	O
project	O
is	O
to	O
document	O
hardware	O
,	O
and	O
so	O
MAME	B-Device
takes	O
a	O
somewhat	O
purist	O
view	O
of	O
emulation	B-Application
,	O
prohibiting	O
programming	O
hacks	O
that	O
might	O
make	O
a	O
game	O
easier	O
to	O
run	O
at	O
the	O
expense	O
of	O
emulation	B-Application
accuracy	O
.	O
</s>
<s>
Components	O
such	O
as	O
CPUs	O
are	O
emulated	B-Application
at	O
a	O
low	O
level	O
(	O
meaning	O
individual	O
instructions	O
are	O
emulated	B-Application
)	O
whenever	O
possible	O
,	O
and	O
high-level	B-Device
emulation	I-Device
(	O
HLE	O
)	O
is	O
only	O
used	O
when	O
a	O
chip	O
is	O
completely	O
undocumented	O
and	O
cannot	O
be	O
reverse-engineered	O
in	O
detail	O
.	O
</s>
<s>
Signal	O
level	O
emulation	B-Application
is	O
used	O
to	O
emulate	O
audio	O
circuitry	O
that	O
consists	O
of	O
analog	O
components	O
.	O
</s>
<s>
MAME	B-Device
emulates	B-Application
well	O
over	O
a	O
thousand	O
different	O
arcade	O
system	O
boards	O
,	O
a	O
majority	O
of	O
which	O
are	O
completely	O
undocumented	O
and	O
custom	O
designed	O
to	O
run	O
either	O
a	O
single	O
game	O
or	O
a	O
very	O
small	O
number	O
of	O
them	O
.	O
</s>
<s>
The	O
approach	O
MAME	B-Device
takes	O
with	O
regards	O
to	O
accuracy	O
is	O
an	O
incremental	O
one	O
;	O
systems	O
are	O
emulated	B-Application
as	O
accurately	O
as	O
they	O
reasonably	O
can	O
be	O
.	O
</s>
<s>
Bootleg	B-General_Concept
copies	O
of	O
games	O
are	O
often	O
the	O
first	O
to	O
be	O
emulated	B-Application
,	O
with	O
proper	O
(	O
and	O
copy	O
protected	O
)	O
versions	O
emulated	B-Application
later	O
.	O
</s>
<s>
Besides	O
encryption	O
,	O
arcade	O
games	O
were	O
usually	O
protected	O
with	O
custom	O
microcontroller	B-Architecture
units	I-Architecture
(	O
MCUs	O
)	O
that	O
implemented	O
a	O
part	O
of	O
the	O
game	O
logic	O
or	O
some	O
other	O
important	O
functions	O
.	O
</s>
<s>
Emulation	B-Application
of	O
these	O
chips	O
is	O
preferred	O
even	O
when	O
they	O
have	O
little	O
or	O
no	O
immediately	O
visible	O
effect	O
on	O
the	O
game	O
itself	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
monster	O
behavior	O
in	O
Bubble	B-Application
Bobble	I-Application
was	O
not	O
perfected	O
until	O
the	O
code	O
and	O
data	O
contained	O
with	O
the	O
custom	O
MCU	O
was	O
dumped	O
through	O
the	O
decapping	O
of	O
the	O
chip	O
.	O
</s>
<s>
This	O
results	O
in	O
the	O
ROM	B-Device
set	O
requirements	O
changing	O
as	O
the	O
games	O
are	O
emulated	B-Application
to	O
a	O
more	O
and	O
more	O
accurate	O
degree	O
,	O
causing	O
older	O
versions	O
of	O
the	O
ROM	B-Device
set	O
becoming	O
unusable	O
in	O
newer	O
versions	O
of	O
MAME	B-Device
.	O
</s>
<s>
Portability	O
and	O
generality	O
are	O
also	O
important	O
to	O
MAME	B-Device
.	O
</s>
<s>
MAME	B-Device
does	O
not	O
currently	O
take	O
advantage	O
of	O
hardware	O
acceleration	O
to	O
speed	O
up	O
the	O
rendering	O
of	O
3D	O
graphics	O
,	O
in	O
part	O
because	O
of	O
the	O
lack	O
of	O
a	O
stable	O
cross-platform	O
3D	O
API	O
,	O
and	O
in	O
part	O
because	O
software	O
rendering	O
can	O
,	O
in	O
theory	O
,	O
be	O
an	O
exact	O
reproduction	O
of	O
the	O
various	O
custom	O
3D	O
rendering	O
approaches	O
that	O
were	O
used	O
in	O
the	O
arcade	O
games	O
.	O
</s>
<s>
Owning	O
and	O
distributing	O
MAME	B-Device
itself	O
is	O
legal	O
in	O
most	O
countries	O
,	O
as	O
it	O
is	O
merely	O
an	O
emulator	B-Application
.	O
</s>
<s>
Companies	O
such	O
as	O
Sony	O
have	O
attempted	O
in	O
court	O
to	O
prevent	O
other	O
software	O
such	O
as	O
Virtual	B-Operating_System
Game	I-Operating_System
Station	I-Operating_System
,	O
a	O
Sony	B-Device
PlayStation	I-Device
emulator	B-Application
from	O
being	O
sold	O
,	O
but	O
they	O
have	O
been	O
ultimately	O
unsuccessful	O
.	O
</s>
<s>
MAME	B-Device
itself	O
has	O
thus	O
far	O
not	O
been	O
the	O
subject	O
of	O
any	O
court	O
cases	O
.	O
</s>
<s>
However	O
,	O
some	O
countries	O
(	O
including	O
the	O
US	O
)	O
allow	O
the	O
owner	O
of	O
a	O
board	O
to	O
transfer	O
data	O
contained	O
in	O
its	O
ROM	B-Device
chips	I-Device
to	O
a	O
personal	O
computer	O
or	O
other	O
device	O
they	O
own	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
2003	O
Atari	O
made	O
MAME-compatible	O
ROMs	O
for	O
27	O
of	O
its	O
arcade	O
games	O
available	O
on	O
the	O
Internet	O
site	O
Star	O
ROMs	O
.	O
</s>
<s>
Other	O
copyright	O
holders	O
have	O
released	O
games	O
which	O
are	O
no	O
longer	O
commercially	O
viable	O
free	O
of	O
charge	O
to	O
the	O
public	O
under	O
licenses	B-License
that	O
prohibit	O
commercial	O
use	O
of	O
the	O
games	O
.	O
</s>
<s>
Many	O
of	O
these	O
games	O
may	O
be	O
downloaded	O
legally	O
from	O
the	O
official	O
MAME	B-Device
web	O
site	O
.	O
</s>
<s>
The	O
Spanish	O
arcade	O
game	O
developer	O
Gaelco	O
has	O
also	O
released	O
World	B-Application
Rally	I-Application
for	O
non-commercial	O
use	O
on	O
their	O
website	O
.	O
</s>
<s>
The	O
MAME	B-Device
community	O
has	O
distanced	O
itself	O
from	O
other	O
groups	O
redistributing	O
ROMs	O
via	O
the	O
Internet	O
or	O
physical	O
media	O
,	O
claiming	O
they	O
are	O
blatantly	O
infringing	O
copyright	O
and	O
harm	O
the	O
project	O
by	O
potentially	O
bringing	O
it	O
into	O
disrepute	O
.	O
</s>
<s>
In	O
addition	O
,	O
many	O
bootleg	B-General_Concept
game	O
systems	O
,	O
such	O
as	O
arcade	O
multi	O
carts	O
,	O
often	O
use	O
versions	O
of	O
MAME	B-Device
to	O
run	O
their	O
games	O
.	O
</s>
<s>
MAME	B-Device
was	O
formerly	O
distributed	O
under	O
a	O
custom	O
self-written	O
copyleft	B-License
license	I-License
,	O
called	O
the	O
"	O
MAME	B-Device
license	B-License
"	O
or	O
the	O
"	O
MAME-like	O
license	B-License
"	O
,	O
which	O
was	O
adopted	O
also	O
by	O
other	O
projects	O
,	O
e.g.	O
</s>
<s>
Visual	B-Application
Pinball	I-Application
.	O
</s>
<s>
This	O
license	B-License
ensures	O
the	O
availability	O
of	O
the	O
licensed	O
program	O
's	O
source	O
code	O
,	O
whilst	O
the	O
redistribution	O
of	O
the	O
program	O
in	O
commercial	O
activities	O
is	O
prohibited	O
.	O
</s>
<s>
Due	O
to	O
this	O
clause	O
,	O
the	O
license	B-License
is	O
incompatible	O
with	O
the	O
OSI	O
's	O
Open	B-License
Source	I-License
Definition	I-License
and	O
the	O
FSF	B-Operating_System
's	O
Free	B-Application
Software	I-Application
Definition	I-Application
,	O
and	O
as	O
such	O
is	O
not	O
considered	O
an	O
open	B-Application
source	I-Application
,	O
or	O
free	B-License
software	I-License
license	I-License
,	O
respectively	O
.	O
</s>
<s>
The	O
non-commercial	O
clause	O
was	O
designed	O
to	O
prevent	O
arcade	O
operators	O
from	O
installing	O
MAME	B-Device
cabinets	I-Device
and	O
profiting	O
from	O
the	O
works	O
of	O
the	O
original	O
manufacturers	O
of	O
the	O
games	O
.	O
</s>
<s>
The	O
ambiguity	O
of	O
the	O
definition	O
"	O
commercial	O
"	O
lead	O
to	O
legal	O
problems	O
with	O
the	O
license	B-License
.	O
</s>
<s>
Since	O
March	O
2016	O
with	O
version	O
0.172	O
,	O
MAME	B-Device
itself	O
switched	O
,	O
by	O
dual	B-License
licensing	I-License
,	O
to	O
common	O
free	B-License
software	I-License
licenses	I-License
,	O
the	O
BSD-3-Clause	B-Operating_System
license	B-License
,	O
and	O
the	O
GPL-2.0-or-later	B-License
license	B-License
.	O
</s>
<s>
However	O
,	O
old	O
versions	O
remain	O
licensed	O
under	O
the	O
original	O
license	B-License
.	O
</s>
