<s>
IRIX	B-Operating_System
(	O
)	O
is	O
a	O
discontinued	O
operating	B-General_Concept
system	I-General_Concept
developed	O
by	O
Silicon	O
Graphics	O
(	O
SGI	O
)	O
to	O
run	O
on	O
the	O
company	O
's	O
proprietary	B-Application
MIPS	B-Device
workstations	O
and	O
servers	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
with	O
BSD	B-Operating_System
extensions	O
.	O
</s>
<s>
In	O
IRIX	B-Operating_System
,	O
SGI	O
originated	O
the	O
XFS	B-Application
file	O
system	O
and	O
the	O
industry-standard	O
OpenGL	B-Application
graphics	O
system	O
.	O
</s>
<s>
SGI	O
originated	O
the	O
IRIX	B-Operating_System
name	O
in	O
the	O
1988	O
release	O
3.0	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
SGI	O
IRIS	O
4D	O
series	O
of	O
workstations	O
and	O
servers	O
.	O
</s>
<s>
The	O
"	O
4D1-	O
"	O
prefix	O
continued	O
to	O
be	O
used	O
in	O
official	O
documentation	O
to	O
prefix	O
IRIX	B-Operating_System
release	O
numbers	O
.	O
</s>
<s>
Prior	O
to	O
the	O
IRIS	O
4D	O
,	O
SGI	O
bundled	O
the	O
GL2	O
operating	B-General_Concept
system	I-General_Concept
,	O
based	O
on	O
UniSoft	B-Operating_System
UniPlus	B-Operating_System
System	B-Operating_System
V	I-Operating_System
Unix	I-Operating_System
,	O
and	O
using	O
the	O
proprietary	B-Application
MEX	O
(	O
Multiple	O
EXposure	O
)	O
windowing	B-Application
system	I-Application
.	O
</s>
<s>
IRIX	B-Operating_System
3.x	O
is	O
based	O
on	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
Release	O
3	O
with	O
4.3BSD	B-Operating_System
enhancements	O
,	O
and	O
incorporates	O
the	O
4Sight	B-Operating_System
windowing	B-Application
system	I-Application
,	O
based	O
on	O
NeWS	O
and	O
IRIS	B-Library
GL	I-Library
.	O
</s>
<s>
SGI	O
's	O
own	O
Extent	B-Operating_System
File	I-Operating_System
System	I-Operating_System
(	O
EFS	B-Operating_System
)	O
replaces	O
the	O
System	B-Operating_System
V	I-Operating_System
filesystem	O
.	O
</s>
<s>
IRIX	B-Operating_System
4.0	O
,	O
released	O
in	O
1991	O
,	O
replaces	O
4Sight	B-Operating_System
with	O
the	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
(	O
X11R4	B-Operating_System
)	O
,	O
the	O
4Dwm	B-Device
window	B-Application
manager	I-Application
providing	O
a	O
similar	O
look	O
and	O
feel	O
to	O
4Sight	B-Operating_System
.	O
</s>
<s>
IRIX	B-Operating_System
5.0	O
,	O
released	O
in	O
1993	O
,	O
incorporates	O
certain	O
features	O
of	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
Release	O
4	O
,	O
including	O
ELF	O
executables	O
.	O
</s>
<s>
IRIX	B-Operating_System
5.3	O
introduced	O
the	O
XFS	B-Application
journaling	B-Application
file	I-Application
system	I-Application
.	O
</s>
<s>
In	O
1994	O
,	O
IRIX	B-Operating_System
6.0	O
added	O
support	O
for	O
the	O
64-bit	O
MIPS	B-Device
R8000	B-General_Concept
processor	O
,	O
but	O
is	O
otherwise	O
similar	O
to	O
IRIX	B-Operating_System
5.2	O
.	O
</s>
<s>
Later	O
6.x	O
releases	O
support	O
other	O
members	O
of	O
the	O
MIPS	B-Device
processor	O
family	O
in	O
64-bit	O
mode	O
.	O
</s>
<s>
IRIX	B-Operating_System
6.3	O
was	O
released	O
for	O
the	O
SGI	B-Device
O2	I-Device
workstation	O
only	O
.	O
</s>
<s>
IRIX	B-Operating_System
6.4	O
improved	O
multiprocessor	B-Operating_System
scalability	O
for	O
the	O
Octane	B-Device
,	O
Origin	B-Application
2000	I-Application
,	O
and	O
Onyx2	B-General_Concept
systems	O
.	O
</s>
<s>
The	O
Origin	B-Application
2000	I-Application
and	O
Onyx2	B-General_Concept
IRIX	B-Operating_System
6.4	O
was	O
marketed	O
as	O
"	O
Cellular	O
IRIX	B-Operating_System
"	O
,	O
although	O
it	O
only	O
incorporates	O
some	O
features	O
from	O
the	O
original	O
Cellular	O
IRIX	B-Operating_System
distributed	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
project	O
.	O
</s>
<s>
The	O
last	O
major	O
version	O
of	O
IRIX	B-Operating_System
is	O
6.5	O
,	O
released	O
in	O
May	O
1998	O
.	O
</s>
<s>
New	O
minor	B-General_Concept
versions	I-General_Concept
of	O
IRIX	B-Operating_System
6.5	O
were	O
released	O
every	O
quarter	O
until	O
2005	O
,	O
and	O
then	O
four	O
minor	B-General_Concept
releases	I-General_Concept
.	O
</s>
<s>
Through	O
version	O
6.5.22	O
,	O
there	O
are	O
two	O
branches	O
of	O
each	O
release	O
:	O
a	O
maintenance	B-General_Concept
release	I-General_Concept
(	O
identified	O
by	O
an	O
"	O
m	O
"	O
suffix	O
)	O
that	O
includes	O
only	O
fixes	O
to	O
the	O
original	O
IRIX	B-Operating_System
6.5	O
code	O
,	O
and	O
a	O
feature	O
release	O
(	O
with	O
an	O
"	O
f	O
"	O
suffix	O
)	O
that	O
includes	O
improvements	O
and	O
enhancements	O
.	O
</s>
<s>
An	O
overlay	O
upgrade	O
from	O
6.5.x	O
to	O
the	O
6.5.22	O
maintenance	B-General_Concept
release	I-General_Concept
was	O
available	O
as	O
a	O
free	O
download	O
,	O
whereas	O
versions	O
6.5.23	O
and	O
higher	O
required	O
an	O
active	O
Silicon	O
Graphics	O
support	O
contract	O
.	O
</s>
<s>
A	O
2001	O
Computerworld	O
review	O
found	O
IRIX	B-Operating_System
in	O
a	O
"	O
critical	O
"	O
state	O
.	O
</s>
<s>
SGI	O
had	O
been	O
moving	O
its	O
efforts	O
to	O
Linux	B-Application
and	O
the	O
Windows-based	O
SGI	B-Device
Visual	I-Device
Workstation	I-Device
but	O
MIPS	B-Device
and	O
IRIX	B-Operating_System
customers	O
convinced	O
SGI	O
to	O
continue	O
to	O
support	O
its	O
platform	O
through	O
2006	O
.	O
</s>
<s>
On	O
September	O
6	O
,	O
2006	O
,	O
an	O
SGI	O
press	O
release	O
announced	O
the	O
end	O
of	O
the	O
MIPS	B-Device
and	O
IRIX	B-Operating_System
product	O
lines	O
.	O
</s>
<s>
Much	O
of	O
IRIX	B-Operating_System
's	O
core	O
technology	O
has	O
been	O
open	O
sourced	O
and	O
ported	O
by	O
SGI	O
to	O
Linux	B-Application
,	O
including	O
XFS	B-Application
.	O
</s>
<s>
All	O
SGI	O
hardware	O
produced	O
after	O
2007	O
is	O
based	O
on	O
either	O
IA-64	B-General_Concept
or	O
x86-64	B-Device
architecture	O
,	O
so	O
it	O
is	O
incapable	O
of	O
running	O
IRIX	B-Operating_System
and	O
is	O
instead	O
intended	O
for	O
Red	O
Hat	O
Enterprise	O
Linux	B-Application
or	O
SUSE	O
Linux	B-Application
Enterprise	O
Server	O
.	O
</s>
<s>
HPE	O
has	O
not	O
stated	O
any	O
plans	O
for	O
IRIX	B-Operating_System
development	O
or	O
source	O
code	O
release	O
.	O
</s>
<s>
IRIX	B-Operating_System
6.5	O
is	O
compliant	O
with	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
Release	O
4	O
,	O
UNIX	B-Application
95	O
,	O
and	O
POSIX	O
(	O
including	O
1e/2c	O
draft	O
15	O
ACLs	O
and	O
Capabilities	O
)	O
.	O
</s>
<s>
In	O
the	O
early	O
1990s	O
,	O
IRIX	B-Operating_System
was	O
a	O
leader	O
in	O
Symmetric	B-Operating_System
Multi-Processing	I-Operating_System
(	O
SMP	O
)	O
,	O
scalable	O
from	O
1	O
to	O
more	O
than	O
1024	O
processors	O
with	O
a	O
single	O
system	O
image	O
.	O
</s>
<s>
IRIX	B-Operating_System
has	O
strong	O
support	O
for	O
real-time	O
disk	O
and	O
graphics	O
I/O	O
.	O
</s>
<s>
IRIX	B-Operating_System
was	O
widely	O
used	O
for	O
the	O
1990s	O
and	O
2000s	O
,	O
in	O
the	O
computer	O
animation	O
and	O
scientific	B-Application
visualization	I-Application
industries	O
due	O
to	O
its	O
large	O
application	O
base	O
and	O
high	O
performance	O
.	O
</s>
<s>
IRIX	B-Operating_System
is	O
one	O
of	O
the	O
first	O
Unix	B-Application
versions	O
to	O
feature	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
for	O
the	O
main	O
desktop	O
environment	O
.	O
</s>
<s>
IRIX	B-Device
Interactive	I-Device
Desktop	I-Device
uses	O
the	O
4Dwm	B-Device
X	B-Application
window	I-Application
manager	I-Application
with	O
a	O
custom	O
look	O
designed	O
using	O
the	O
Motif	B-Application
widget	I-Application
toolkit	I-Application
.	O
</s>
<s>
IRIX	B-Operating_System
is	O
the	O
originator	O
of	O
the	O
industry	O
standard	O
OpenGL	B-Application
for	O
graphics	O
chips	O
and	O
Image	O
processing	O
libraries	O
.	O
</s>
<s>
IRIX	B-Operating_System
uses	O
the	O
MIPSPro	B-Application
Compiler	O
for	O
both	O
its	O
front	O
end	O
and	O
back	O
end	O
.	O
</s>
<s>
The	O
Workshop	O
GUI	B-Application
IDE	O
is	O
used	O
for	O
development	O
.	O
</s>
<s>
Other	O
tools	O
include	O
Speedshop	O
for	O
performance	O
tuning	O
,	O
and	O
Performance	B-Protocol
Co-Pilot	I-Protocol
.	O
</s>
