<s>
Binary-code	B-General_Concept
compatibility	I-General_Concept
(	O
binary	B-General_Concept
compatible	I-General_Concept
or	O
object-code-compatible	O
)	O
is	O
a	O
property	O
of	O
a	O
computer	O
system	O
,	O
meaning	O
that	O
it	O
can	O
run	O
the	O
same	O
executable	B-Application
code	I-Application
,	O
typically	O
machine	B-Language
code	I-Language
for	O
a	O
general-purpose	O
computer	O
CPU	B-General_Concept
,	O
that	O
another	O
computer	O
system	O
can	O
run	O
.	O
</s>
<s>
Source-code	B-General_Concept
compatibility	I-General_Concept
,	O
on	O
the	O
other	O
hand	O
,	O
means	O
that	O
recompilation	B-Language
or	O
interpretation	B-Application
is	O
necessary	O
before	O
the	O
program	O
can	O
be	O
run	O
on	O
the	O
compatible	O
system	O
.	O
</s>
<s>
For	O
a	O
compiled	B-Language
program	O
on	O
a	O
general	O
operating	B-General_Concept
system	I-General_Concept
,	O
binary	B-General_Concept
compatibility	I-General_Concept
often	O
implies	O
that	O
not	O
only	O
the	O
CPUs	O
(	O
instruction	B-General_Concept
sets	I-General_Concept
)	O
of	O
the	O
two	O
computers	O
are	O
binary	B-General_Concept
compatible	I-General_Concept
,	O
but	O
also	O
that	O
interfaces	O
and	O
behaviours	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
(	O
OS	O
)	O
and	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-Application
)	O
,	O
and	O
the	O
application	B-Operating_System
binary	I-Operating_System
interfaces	I-Operating_System
(	O
ABIs	O
)	O
corresponding	O
to	O
those	O
APIs	B-Application
,	O
are	O
sufficiently	O
equal	O
,	O
i.e.	O
</s>
<s>
A	O
term	O
like	O
backward-compatible	B-General_Concept
usually	O
implies	O
object-code	B-General_Concept
compatibility	I-General_Concept
.	O
</s>
<s>
Older	O
executable	B-Application
code	I-Application
will	O
thus	O
run	O
unchanged	O
on	O
the	O
newer	O
product	O
.	O
</s>
<s>
For	O
a	O
compiled	B-Language
program	O
running	O
directly	O
on	O
a	O
CPU	B-General_Concept
under	O
an	O
OS	O
,	O
a	O
"	O
binary	B-General_Concept
compatible	I-General_Concept
operating	B-General_Concept
system	I-General_Concept
"	O
primarily	O
means	O
application	B-Operating_System
binary	I-Operating_System
interface	I-Operating_System
(	O
ABI	O
)	O
compatibility	B-Device
with	O
another	O
system	O
.	O
</s>
<s>
However	O
,	O
it	O
also	O
often	O
implies	O
that	O
APIs	B-Application
that	O
the	O
application	O
depends	O
on	O
,	O
directly	O
or	O
indirectly	O
(	O
such	O
as	O
the	O
Windows	B-Library
API	I-Library
,	O
for	O
example	O
)	O
,	O
are	O
sufficiently	O
similar	O
.	O
</s>
<s>
Hardware	O
(	O
besides	O
the	O
CPU	B-General_Concept
,	O
such	O
as	O
for	O
graphics	O
)	O
and	O
peripherals	O
that	O
an	O
application	O
accesses	O
may	O
also	O
be	O
a	O
factor	O
for	O
full	O
compatibility	B-Device
,	O
although	O
many	O
hardware	O
differences	O
are	O
hidden	O
by	O
modern	O
APIs	B-Application
(	O
often	O
partly	O
supplied	O
by	O
the	O
OS	O
itself	O
and	O
partly	O
by	O
specific	O
device	B-Application
drivers	I-Application
)	O
.	O
</s>
<s>
In	O
other	O
cases	O
,	O
a	O
general	O
porting	O
of	O
the	O
software	O
must	O
be	O
used	O
to	O
make	O
non-binary-compatible	O
programs	O
work	O
.	O
</s>
<s>
Binary	B-General_Concept
compatibility	I-General_Concept
is	O
a	O
major	O
benefit	O
when	O
developing	O
computer	O
programs	O
that	O
are	O
to	O
be	O
run	O
on	O
multiple	O
OSes	O
.	O
</s>
<s>
Several	O
Unix-based	O
OSes	O
,	O
such	O
as	O
FreeBSD	B-Operating_System
or	O
NetBSD	B-Device
,	O
offer	O
binary	B-General_Concept
compatibility	I-General_Concept
with	O
more	O
popular	O
OSes	O
,	O
such	O
as	O
Linux-derived	O
ones	O
,	O
since	O
most	O
binary	B-Application
executables	I-Application
are	O
not	O
commonly	O
distributed	O
for	O
such	O
OSes	O
.	O
</s>
<s>
Most	O
OSes	O
provide	O
binary	B-General_Concept
compatibility	I-General_Concept
,	O
in	O
each	O
version	O
of	O
the	O
OS	O
,	O
for	O
most	O
binaries	O
built	O
to	O
run	O
on	O
earlier	O
versions	O
of	O
the	O
OS	O
.	O
</s>
<s>
For	O
example	O
,	O
many	O
executables	B-Application
compiled	B-Language
for	O
Windows	B-Application
3.1	I-Application
,	O
Windows	B-Application
95	I-Application
or	O
Windows	B-Application
2000	I-Application
can	O
also	O
be	O
run	O
on	O
Windows	B-Application
XP	I-Application
or	O
Windows	B-Device
7	I-Device
,	O
and	O
many	O
applications	O
for	O
DOS	B-Device
ran	O
on	O
much	O
newer	O
versions	O
of	O
Windows	O
up	O
to	O
Windows	O
10	O
for	O
as	O
long	O
as	O
the	O
NTVDM	O
was	O
supported	O
.	O
</s>
<s>
For	O
a	O
digital	O
processor	O
implemented	O
in	O
hardware	O
,	O
binary	B-General_Concept
compatibility	I-General_Concept
means	O
that	O
(	O
a	O
large	O
subset	O
of	O
)	O
machine	B-Language
code	I-Language
produced	O
for	O
another	O
processor	O
can	O
be	O
correctly	O
executed	O
and	O
has	O
(	O
much	O
)	O
the	O
same	O
effect	O
as	O
on	O
the	O
other	O
processor	O
.	O
</s>
<s>
This	O
is	O
quite	O
common	O
among	O
many	O
processor	O
families	O
,	O
although	O
it	O
is	O
rather	O
uncommon	O
among	O
the	O
ubiquitous	O
small	O
embedded	B-Architecture
systems	I-Architecture
built	O
around	O
such	O
processors	O
.	O
</s>
<s>
Full	O
machine	B-Language
code	I-Language
compatibility	B-Device
would	O
here	O
imply	O
exactly	O
the	O
same	O
layout	O
of	O
interrupt	B-General_Concept
service	I-General_Concept
routines	I-General_Concept
,	O
I/O	O
-ports	O
,	O
hardware	B-General_Concept
registers	I-General_Concept
,	O
counter/timers	O
,	O
external	O
interfaces	O
and	O
so	O
on	O
.	O
</s>
<s>
For	O
a	O
more	O
complex	O
embedded	B-Architecture
system	I-Architecture
using	O
more	O
abstraction	B-Architecture
layers	I-Architecture
(	O
sometimes	O
on	O
the	O
border	O
to	O
a	O
general	O
computer	O
,	O
such	O
as	O
a	O
mobile	O
phone	O
)	O
,	O
this	O
may	O
be	O
different	O
.	O
</s>
<s>
Binary	B-General_Concept
compatible	I-General_Concept
operating	B-General_Concept
systems	I-General_Concept
are	O
OSes	O
that	O
aim	O
to	O
implement	O
binary	B-General_Concept
compatibility	I-General_Concept
with	O
another	O
OS	O
,	O
or	O
another	O
variant	O
of	O
the	O
same	O
brand	O
.	O
</s>
<s>
This	O
means	O
that	O
they	O
are	O
ABI-compatible	O
(	O
for	O
application	B-Operating_System
binary	I-Operating_System
interface	I-Operating_System
)	O
.	O
</s>
<s>
As	O
the	O
job	O
of	O
an	O
OS	O
is	O
to	O
run	O
programs	O
,	O
the	O
instruction	B-General_Concept
set	I-General_Concept
architectures	I-General_Concept
running	O
the	O
OSes	O
have	O
to	O
be	O
the	O
same	O
or	O
compatible	O
.	O
</s>
<s>
Otherwise	O
,	O
programs	O
can	O
be	O
employed	O
within	O
a	O
CPU	B-Application
emulator	I-Application
or	O
a	O
faster	O
dynamic	O
translation	O
mechanism	O
to	O
make	O
them	O
compatible	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
is	O
not	O
compatible	O
with	O
Windows	O
.	O
</s>
<s>
This	O
does	O
not	O
mean	O
that	O
Linux	B-Application
ca	O
n't	O
be	O
binary	B-General_Concept
compatible	I-General_Concept
with	O
Windows	O
applications	O
.	O
</s>
<s>
Additional	O
software	O
,	O
Wine	B-Application
,	O
is	O
available	O
that	O
does	O
that	O
to	O
some	O
degree	O
.	O
</s>
<s>
The	O
ReactOS	B-Application
development	O
effort	O
seeks	O
to	O
create	O
an	O
open-source	B-Application
,	O
free	B-Application
software	I-Application
OS	O
that	O
is	O
binary	B-General_Concept
compatible	I-General_Concept
with	O
Microsoft	O
's	O
Windows	B-Device
NT	I-Device
family	I-Device
of	O
OSes	O
using	O
Wine	B-Application
for	O
application	O
compatibility	B-Device
and	O
reimplementing	O
the	O
Windows	O
kernel	B-Operating_System
for	O
additional	O
compatibility	B-Device
such	O
as	O
for	O
drivers	O
whereas	O
Linux	B-Application
would	O
use	O
Linux	B-Application
drivers	O
not	O
Windows	O
drivers	O
.	O
</s>
<s>
FreeBSD	B-Operating_System
and	O
other	O
members	O
of	O
the	O
BSD	B-Operating_System
family	O
have	O
binary	B-General_Concept
compatibility	I-General_Concept
with	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
in	O
usermode	B-Operating_System
by	O
translating	O
Linux	B-Application
system	O
calls	O
into	O
BSD	B-Operating_System
ones	O
.	O
</s>
<s>
This	O
enables	O
the	O
application	O
and	O
libraries	O
code	O
that	O
run	O
on	O
Linux-based	O
OSes	O
to	O
be	O
run	O
on	O
BSD	B-Operating_System
as	O
well	O
.	O
</s>
<s>
Note	O
that	O
a	O
binary	B-General_Concept
compatible	I-General_Concept
OS	O
is	O
different	O
from	O
running	O
an	O
alternative	O
OS	O
through	O
virtualization	B-General_Concept
or	O
emulation	B-Application
,	O
which	O
is	O
done	O
to	O
run	O
software	O
within	O
the	O
alternative	O
OS	O
in	O
the	O
case	O
when	O
the	O
host	O
OS	O
is	O
n't	O
compatible	O
.	O
</s>
<s>
Sometimes	O
virtualization	B-General_Concept
is	O
provided	O
with	O
the	O
host	O
OS	O
(	O
or	O
such	O
software	O
can	O
be	O
obtained	O
)	O
,	O
which	O
effectively	O
makes	O
the	O
host	O
OS	O
compatible	O
with	O
programs	O
.	O
</s>
<s>
For	O
example	O
,	O
Windows	B-Application
XP	I-Application
Mode	O
for	O
Windows	B-Device
7	I-Device
allows	O
users	O
to	O
run	O
a	O
64-bit	B-Device
version	O
of	O
Windows	B-Device
7	I-Device
and	O
enable	O
old	O
software	O
to	O
still	O
work	O
in	O
a	O
32-bit	O
virtual	B-Architecture
machine	I-Architecture
running	O
Windows	B-Application
XP	I-Application
;	O
VMware	O
Workstation/VMware	O
Fusion	O
,	O
Parallels	B-Operating_System
Workstation	I-Operating_System
,	O
and	O
Windows	B-Application
Virtual	I-Application
PC	I-Application
allow	O
other	O
OSes	O
to	O
be	O
run	O
on	O
Windows	O
,	O
Linux	B-Application
,	O
and	O
macOS	B-Operating_System
.	O
</s>
<s>
For	O
another	O
example	O
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
on	O
the	O
PowerPC	B-Architecture
had	O
the	O
ability	O
to	O
run	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
and	O
earlier	O
application	O
software	O
through	O
Classic	O
—	O
but	O
this	O
did	O
not	O
make	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
a	O
binary	B-General_Concept
compatible	I-General_Concept
OS	O
with	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
.	O
</s>
<s>
Instead	O
,	O
the	O
Classic	O
environment	O
was	O
actually	O
running	O
Mac	B-Operating_System
OS	I-Operating_System
9.1	I-Operating_System
in	O
a	O
virtual	B-Architecture
machine	I-Architecture
,	O
running	O
as	O
a	O
normal	O
process	O
inside	O
of	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
