<s>
The	O
Intel	B-Operating_System
Binary	I-Operating_System
Compatibility	I-Operating_System
Standard	I-Operating_System
(	O
iBCS	O
)	O
is	O
a	O
standardized	O
application	B-Operating_System
binary	I-Operating_System
interface	I-Operating_System
(	O
ABI	O
)	O
for	O
Unix	B-Application
operating	I-Application
systems	I-Application
on	O
Intel-386-compatible	O
computers	O
,	O
published	O
by	O
AT&T	O
,	O
Intel	O
and	O
SCO	O
in	O
1988	O
,	O
and	O
updated	O
in	O
1990	O
.	O
</s>
<s>
It	O
extends	O
source-level	O
standards	O
such	O
as	O
POSIX	O
and	O
XPG3	O
by	O
standardizing	O
various	O
operating	O
system	O
interfaces	O
,	O
including	O
the	O
filesystem	B-Application
hierarchy	I-Application
layout	I-Application
(	O
i.e.	O
,	O
the	O
locations	O
of	O
system	O
files	O
and	O
installed	O
programs	O
)	O
,	O
so	O
that	O
Unix	B-Application
programs	O
would	O
run	O
on	O
the	O
various	O
vendor-specific	O
Unix	B-Application
implementations	O
for	O
Intel	O
hardware	O
(	O
such	O
as	O
Xenix	B-Application
,	O
SCO	B-Operating_System
Unix	I-Operating_System
and	O
System	B-Operating_System
V	I-Operating_System
implementations	O
)	O
.	O
</s>
<s>
The	O
second	O
edition	O
,	O
announced	O
in	O
1990	O
,	O
added	O
an	O
interface	O
specification	O
for	O
VGA	B-Protocol
graphics	I-Protocol
.	O
</s>
<s>
iBCS	O
,	O
edition	O
2	O
,	O
was	O
supported	O
by	O
various	O
Unix	B-Application
versions	O
,	O
such	O
as	O
UnixWare	B-Operating_System
and	O
third-party	O
implementations	O
.	O
</s>
<s>
A	O
Linux	B-Application
implementation	O
was	O
developed	O
ca	O
.	O
</s>
<s>
1994	O
,	O
enabling	O
Linux	B-Application
to	O
run	O
commercial	O
Unix	B-Application
applications	O
such	O
as	O
WordPerfect	B-Application
.	O
</s>
