<s>
The	O
universal	B-Operating_System
binary	I-Operating_System
format	I-Operating_System
is	O
a	O
format	O
for	O
executable	B-Application
files	I-Application
that	O
run	O
natively	O
on	O
either	O
PowerPC	B-Architecture
or	O
Intel-manufactured	O
IA-32	B-Device
or	O
Intel	O
64	O
or	O
ARM64-based	O
Macintosh	B-Device
computers	I-Device
.	O
</s>
<s>
The	O
format	O
originated	O
on	O
NeXTStep	B-Application
as	O
"	O
Multi-Architecture	O
Binaries	O
"	O
,	O
and	O
the	O
concept	O
is	O
more	O
generally	O
known	O
as	O
a	O
fat	O
binary	O
,	O
as	O
seen	O
on	O
Power	B-Device
Macintosh	I-Device
.	O
</s>
<s>
With	O
the	O
release	O
of	O
Mac	B-Device
OS	I-Device
X	I-Device
Snow	I-Device
Leopard	I-Device
,	O
and	O
before	O
that	O
,	O
since	O
the	O
move	O
to	O
64-bit	O
architectures	O
in	O
general	O
,	O
some	O
software	O
publishers	O
such	O
as	O
Mozilla	B-Operating_System
have	O
used	O
the	O
term	O
"	O
universal	O
"	O
to	O
refer	O
to	O
a	O
fat	O
binary	O
that	O
includes	O
builds	O
for	O
both	O
i386	O
(	O
32-bit	O
Intel	O
)	O
and	O
x86_64	O
systems	O
.	O
</s>
<s>
The	O
same	O
mechanism	O
that	O
is	O
used	O
to	O
select	O
between	O
the	O
PowerPC	B-Architecture
or	O
Intel	O
builds	O
of	O
an	O
application	O
is	O
also	O
used	O
to	O
select	O
between	O
the	O
32-bit	O
or	O
64-bit	O
builds	O
of	O
either	O
PowerPC	B-Architecture
or	O
Intel	O
architectures	O
.	O
</s>
<s>
Apple	O
,	O
however	O
,	O
continued	O
to	O
require	O
native	O
compatibility	O
with	O
both	O
PowerPC	B-Architecture
and	O
Intel	O
in	O
order	O
to	O
grant	O
third-party	O
software	O
publishers	O
permission	O
to	O
use	O
Apple	O
's	O
trademarks	O
related	O
to	O
universal	B-Operating_System
binaries	I-Operating_System
.	O
</s>
<s>
Universal	B-Operating_System
binaries	I-Operating_System
were	O
introduced	O
into	O
Mac	B-Application
OS	I-Application
at	O
the	O
2005	O
Apple	O
Worldwide	O
Developers	O
Conference	O
as	O
a	O
means	O
to	O
ease	O
the	O
transition	O
from	O
the	O
existing	O
PowerPC	B-Architecture
architecture	O
to	O
systems	O
based	O
on	O
Intel	O
processors	O
,	O
which	O
began	O
shipping	O
in	O
2006	O
.	O
</s>
<s>
Universal	B-Operating_System
binaries	I-Operating_System
typically	O
include	O
both	O
PowerPC	B-Architecture
and	O
x86	B-Operating_System
versions	O
of	O
a	O
compiled	O
application	O
.	O
</s>
<s>
The	O
operating	B-General_Concept
system	I-General_Concept
detects	O
a	O
universal	B-Operating_System
binary	I-Operating_System
by	O
its	O
header	O
,	O
and	O
executes	O
the	O
appropriate	O
section	O
for	O
the	O
architecture	O
in	O
use	O
.	O
</s>
<s>
Starting	O
with	O
Mac	B-Device
OS	I-Device
X	I-Device
Snow	I-Device
Leopard	I-Device
,	O
only	O
Intel-based	B-Device
Macs	I-Device
are	O
supported	O
,	O
so	O
software	O
that	O
specifically	O
depends	O
upon	O
capabilities	O
present	O
only	O
in	O
Mac	B-Device
OS	I-Device
X	I-Device
10.6	I-Device
or	O
newer	O
will	O
only	O
run	O
on	O
Intel-based	B-Device
Macs	I-Device
and	O
therefore	O
does	O
not	O
require	O
Intel/PPC	O
fat	O
binaries	O
.	O
</s>
<s>
Additionally	O
,	O
starting	O
with	O
OS	B-Application
X	I-Application
Lion	I-Application
,	O
only	O
64-bit	O
Intel	B-Device
Macs	I-Device
are	O
supported	O
,	O
so	O
software	O
that	O
specifically	O
depends	O
on	O
new	O
features	O
in	O
OS	B-Application
X	I-Application
10.7	I-Application
or	O
newer	O
will	O
only	O
run	O
on	O
64-bit	O
processors	O
and	O
therefore	O
does	O
not	O
require	O
32-bit/64	O
-bit	O
fat	O
binaries	O
.	O
</s>
<s>
Fat	O
binaries	O
would	O
only	O
be	O
necessary	O
for	O
software	O
that	O
is	O
designed	O
to	O
have	O
backward	B-General_Concept
compatibility	I-General_Concept
with	O
older	O
versions	O
of	O
Mac	B-Device
OS	I-Device
X	I-Device
running	O
on	O
older	O
hardware	O
.	O
</s>
<s>
Universal	O
2	O
allows	O
applications	O
to	O
run	O
on	O
both	O
Intel	O
x86-64-based	O
and	O
ARM64-based	O
Macintosh	B-Device
computers	I-Device
,	O
to	O
enable	O
the	O
transition	B-Device
to	I-Device
Apple	I-Device
silicon	I-Device
.	O
</s>
<s>
The	O
first	O
is	O
to	O
simply	O
provide	O
two	O
separate	O
binaries	O
,	O
one	O
compiled	O
for	O
the	O
x86	B-Operating_System
architecture	I-Operating_System
and	O
one	O
for	O
the	O
PowerPC	B-Architecture
architecture	O
.	O
</s>
<s>
However	O
,	O
this	O
can	O
be	O
confusing	O
to	O
software	O
users	O
unfamiliar	O
with	O
the	O
difference	O
between	O
the	O
two	O
,	O
although	O
the	O
confusion	O
can	O
be	O
remedied	O
through	O
improved	O
documentation	O
,	O
or	O
the	O
use	O
of	O
hybrid	B-Application
CDs	I-Application
.	O
</s>
<s>
The	O
other	O
alternative	O
is	O
to	O
rely	O
on	O
emulation	B-Application
of	O
one	O
architecture	O
by	O
a	O
system	O
running	O
the	O
other	O
architecture	O
.	O
</s>
<s>
This	O
approach	O
results	O
in	O
lower	O
performance	O
,	O
and	O
is	O
generally	O
regarded	O
an	O
interim	O
solution	O
to	O
be	O
used	O
only	O
until	O
universal	B-Operating_System
binaries	I-Operating_System
or	O
specifically	O
compiled	O
binaries	O
are	O
available	O
as	O
with	O
Rosetta	B-Operating_System
.	O
</s>
<s>
Universal	B-Operating_System
binaries	I-Operating_System
are	O
larger	O
than	O
single-platform	O
binaries	O
,	O
because	O
multiple	O
copies	O
of	O
the	O
compiled	O
code	O
must	O
be	O
stored	O
.	O
</s>
<s>
However	O
,	O
because	O
some	O
non-executable	O
resources	O
are	O
shared	O
by	O
the	O
two	O
architectures	O
,	O
the	O
size	O
of	O
the	O
resulting	O
universal	B-Operating_System
binary	I-Operating_System
can	O
be	O
,	O
and	O
usually	O
is	O
,	O
smaller	O
than	O
the	O
combined	O
sizes	O
of	O
two	O
individual	O
binaries	O
.	O
</s>
<s>
They	O
also	O
do	O
not	O
require	O
extra	O
RAM	B-Architecture
because	O
only	O
one	O
of	O
those	O
two	O
copies	O
is	O
loaded	O
for	O
execution	O
.	O
</s>
<s>
The	O
concept	O
of	O
a	O
universal	B-Operating_System
binary	I-Operating_System
originated	O
with	O
"	O
Multi-Architecture	O
Binaries	O
"	O
in	O
NeXTSTEP	B-Application
,	O
the	O
main	O
architectural	O
foundation	O
of	O
Mac	B-Device
OS	I-Device
X	I-Device
.	O
NeXTSTEP	B-Application
supports	O
universal	B-Operating_System
binaries	I-Operating_System
so	O
that	O
one	O
executable	B-Application
image	O
can	O
run	O
on	O
multiple	O
architectures	O
,	O
including	O
Motorola	O
's	O
m68k	B-Device
,	O
Intel	O
's	O
x86	B-Operating_System
,	O
Sun	O
Microsystems	O
's	O
SPARC	B-Architecture
,	O
and	O
Hewlett-Packard	O
'	O
s	O
PA-RISC	B-Device
.	O
</s>
<s>
NeXTSTEP	B-Application
and	O
macOS	B-Application
use	O
Mach-O	B-Operating_System
archive	O
as	O
the	O
binary	O
format	O
underlying	O
the	O
universal	B-Operating_System
binary	I-Operating_System
.	O
</s>
<s>
Apple	O
previously	O
used	O
a	O
similar	O
technique	O
during	O
the	O
transition	O
from	O
68k	B-Device
processors	O
to	O
PowerPC	B-Architecture
in	O
the	O
mid-1990s	O
.	O
</s>
<s>
These	O
dual-platform	O
executables	B-Application
are	O
called	O
fat	O
binaries	O
,	O
referring	O
to	O
their	O
larger	O
file	O
size	O
.	O
</s>
<s>
Apple	O
's	O
Xcode	B-Operating_System
2.1	O
supports	O
the	O
creation	O
of	O
these	O
files	O
,	O
a	O
new	O
feature	O
in	O
that	O
release	O
.	O
</s>
<s>
A	O
simple	O
application	O
developed	O
with	O
processor-independence	O
in	O
mind	O
might	O
require	O
very	O
few	O
changes	O
to	O
compile	O
as	O
a	O
universal	B-Operating_System
binary	I-Operating_System
,	O
but	O
a	O
complex	O
application	O
designed	O
to	O
take	O
advantage	O
of	O
architecture-specific	O
features	O
might	O
require	O
substantial	O
modification	O
.	O
</s>
<s>
These	O
reasons	O
have	O
been	O
given	O
for	O
the	O
delay	O
between	O
the	O
introduction	O
of	O
Intel-based	O
Macintosh	B-Device
computers	I-Device
and	O
the	O
availability	O
of	O
third-party	O
applications	O
in	O
universal	B-Operating_System
binary	I-Operating_System
format	I-Operating_System
.	O
</s>
<s>
Apple	O
's	O
Xcode	B-Operating_System
2.4	O
takes	O
the	O
concept	O
of	O
universal	B-Operating_System
binaries	I-Operating_System
even	O
further	O
,	O
by	O
allowing	O
four-architecture	O
binaries	O
to	O
be	O
created	O
(	O
32	O
-	O
and	O
64-bit	O
for	O
both	O
Intel	O
and	O
PowerPC	B-Architecture
)	O
,	O
therefore	O
allowing	O
a	O
single	O
executable	B-Application
to	O
take	O
full	O
advantage	O
of	O
the	O
CPU	O
capabilities	O
of	O
any	O
Mac	B-Device
OS	I-Device
X	I-Device
machine	O
.	O
</s>
<s>
Many	O
software	O
developers	O
have	O
provided	O
universal	B-Operating_System
binary	I-Operating_System
updates	O
for	O
their	O
products	O
since	O
the	O
2005	O
WWDC	O
.	O
</s>
<s>
As	O
of	O
December	O
2008	O
,	O
Apple	O
's	O
website	O
listed	O
more	O
than	O
7,500	O
Universal	B-Operating_System
applications	I-Operating_System
.	O
</s>
<s>
On	O
April	O
16	O
,	O
2007	O
,	O
Adobe	O
Systems	O
announced	O
the	O
release	O
of	O
Adobe	B-Operating_System
Creative	I-Operating_System
Suite	I-Operating_System
3	I-Operating_System
,	O
the	O
first	O
version	O
of	O
the	O
application	O
suite	O
in	O
the	O
Universal	B-Operating_System
Binary	I-Operating_System
format	I-Operating_System
.	O
</s>
<s>
From	O
2006	O
to	O
2010	O
,	O
many	O
Mac	B-Device
OS	I-Device
X	I-Device
applications	O
were	O
ported	O
to	O
Universal	B-Operating_System
Binary	I-Operating_System
format	I-Operating_System
,	O
including	O
QuarkXPress	B-Operating_System
,	O
Apple	O
's	O
own	O
Final	B-Operating_System
Cut	I-Operating_System
Studio	I-Operating_System
,	O
Adobe	B-Operating_System
Creative	I-Operating_System
Suite	I-Operating_System
,	O
Microsoft	B-Operating_System
Office	I-Operating_System
2008	I-Operating_System
,	O
and	O
Shockwave	B-Operating_System
Player	I-Operating_System
with	O
version	O
11	O
-	O
after	O
that	O
time	O
most	O
were	O
made	O
Intel-only	O
apps	O
.	O
</s>
<s>
Non-Universal	O
32-bit	O
PowerPC	B-Architecture
programs	O
will	O
run	O
on	O
Intel	B-Device
Macs	I-Device
running	O
Mac	B-Device
OS	I-Device
X	I-Device
10.4	O
,	O
10.5	O
,	O
and	O
10.6	B-Device
(	O
in	O
most	O
cases	O
)	O
,	O
but	O
with	O
non-optimal	O
performance	O
,	O
since	O
they	O
must	O
be	O
translated	O
on-the-fly	O
by	O
Rosetta	B-Operating_System
;	O
they	O
will	O
not	O
run	O
on	O
Mac	B-Application
OS	I-Application
X	I-Application
10.7	I-Application
Lion	I-Application
and	O
later	O
as	O
Rosetta	B-Operating_System
is	O
no	O
longer	O
part	O
of	O
the	O
OS	O
.	O
</s>
<s>
Apple	O
has	O
used	O
the	O
same	O
binary	O
format	O
as	O
Universal	B-Operating_System
Binaries	I-Operating_System
for	O
iOS	B-Application
applications	O
by	O
default	O
on	O
multiple	O
occasions	O
of	O
architectural	O
co-existence	O
:	O
around	O
2010	O
during	O
the	O
armv6-armv7-armv7s	O
transition	O
and	O
around	O
2016	O
during	O
the	O
armv7-arm64	O
transition	O
.	O
</s>
<s>
The	O
App	B-Application
Store	I-Application
automatically	O
thins	O
the	O
binaries	O
.	O
</s>
<s>
On	O
June	O
22	O
,	O
2020	O
,	O
Apple	O
announced	O
a	O
two-year	O
permanent	O
transition	O
from	O
Intel	O
x86-64-based	O
processors	O
to	O
ARM64-based	O
Apple	B-Device
silicon	I-Device
beginning	O
with	O
macOS	B-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
in	O
late	O
2020	O
.	O
</s>
<s>
To	O
aid	O
in	O
this	O
transition	O
,	O
a	O
new	O
Universal	O
2	O
binary	O
was	O
introduced	O
to	O
enable	O
applications	O
to	O
be	O
run	O
on	O
either	O
x86-64-based	O
processors	O
or	O
ARM64-based	O
processors	O
.	O
</s>
<s>
The	O
main	O
tool	O
for	O
handling	O
(	O
creating	O
or	O
splitting	O
)	O
universal	B-Operating_System
binaries	I-Operating_System
is	O
the	O
command	O
found	O
in	O
Xcode	B-Operating_System
.	O
</s>
<s>
The	O
command	O
on	O
macOS	B-Application
and	O
several	O
other	O
Unix-like	B-Operating_System
systems	I-Operating_System
can	O
identify	O
Mach-O	B-Operating_System
universal	B-Operating_System
binaries	I-Operating_System
and	O
report	O
architecture	O
support	O
.	O
</s>
<s>
Snow	B-Device
Leopard	I-Device
's	O
System	B-Application
Profiler	I-Application
provides	O
this	O
information	O
on	O
the	O
Applications	O
tab	O
.	O
</s>
