<s>
OSF/1	B-Operating_System
is	O
a	O
variant	O
of	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
developed	O
by	O
the	O
Open	B-Application
Software	I-Application
Foundation	I-Application
during	O
the	O
late	O
1980s	O
and	O
early	O
1990s	O
.	O
</s>
<s>
OSF/1	B-Operating_System
is	O
one	O
of	O
the	O
first	O
operating	B-General_Concept
systems	I-General_Concept
to	O
have	O
used	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
developed	O
at	O
Carnegie	O
Mellon	O
University	O
,	O
and	O
is	O
probably	O
best	O
known	O
as	O
the	O
native	O
Unix	B-Application
operating	I-Application
system	I-Application
for	O
DEC	B-Device
Alpha	I-Device
architecture	O
systems	O
.	O
</s>
<s>
In	O
1994	O
,	O
after	O
AT&T	O
had	O
sold	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
to	O
Novell	O
and	O
the	O
rival	O
Unix	B-Application
International	O
consortium	O
had	O
disbanded	O
,	O
the	O
Open	B-Application
Software	I-Application
Foundation	I-Application
ceased	O
funding	O
of	O
research	O
and	O
development	O
of	O
OSF/1	B-Operating_System
.	O
</s>
<s>
The	O
Tru64	B-Operating_System
UNIX	I-Operating_System
variant	O
of	O
OSF/1	B-Operating_System
was	O
supported	O
by	O
HP	O
until	O
2012	O
.	O
</s>
<s>
In	O
1988	O
,	O
during	O
the	O
so-called	O
"	O
Unix	B-Application
wars	O
"	O
,	O
Digital	O
Equipment	O
Corporation	O
(	O
DEC	O
)	O
joined	O
with	O
IBM	O
,	O
Hewlett-Packard	O
,	O
and	O
others	O
to	O
form	O
the	O
Open	B-Application
Software	I-Application
Foundation	I-Application
(	O
OSF	O
)	O
to	O
develop	O
a	O
version	O
of	O
Unix	B-Application
named	O
OSF/1	B-Operating_System
.	O
</s>
<s>
The	O
aim	O
was	O
to	O
compete	O
with	O
System	B-Operating_System
V	I-Operating_System
Release	O
4	O
from	O
AT&T	O
Corporation	O
and	O
Sun	O
Microsystems	O
,	O
and	O
it	O
has	O
been	O
argued	O
that	O
a	O
primary	O
goal	O
was	O
for	O
the	O
operating	B-General_Concept
system	I-General_Concept
to	O
be	O
free	O
of	O
AT&T	O
intellectual	O
property	O
.	O
</s>
<s>
The	O
fact	O
that	O
OSF/1	B-Operating_System
is	O
one	O
of	O
the	O
first	O
operating	B-General_Concept
systems	I-General_Concept
to	O
have	O
used	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
is	O
cited	O
as	O
support	O
of	O
this	O
assertion	O
.	O
</s>
<s>
Digital	O
also	O
strongly	O
promoted	O
OSF/1	B-Operating_System
for	O
real-time	B-General_Concept
applications	I-General_Concept
,	O
and	O
with	O
traditional	B-Application
UNIX	I-Application
implementations	O
at	O
the	O
time	O
providing	O
poor	O
real-time	B-General_Concept
support	O
at	O
best	O
,	O
the	O
real-time	B-General_Concept
and	O
multi-threading	B-Operating_System
support	O
can	O
be	O
interpreted	O
as	O
having	O
been	O
heavily	O
dependent	O
on	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
.	O
</s>
<s>
It	O
also	O
incorporates	O
a	O
large	O
part	O
of	O
the	O
BSD	B-Operating_System
kernel	O
(	O
based	O
on	O
the	O
4.3-Reno	O
release	O
)	O
to	O
implement	O
the	O
UNIX	B-Application
API	B-General_Concept
.	O
</s>
<s>
At	O
the	O
time	O
of	O
its	O
introduction	O
,	O
OSF/1	B-Operating_System
became	O
the	O
third	O
major	O
flavor	O
of	O
UNIX	B-Application
together	O
with	O
System	B-Operating_System
V	I-Operating_System
and	O
BSD	B-Operating_System
.	O
</s>
<s>
DEC	O
's	O
first	O
release	O
of	O
OSF/1	B-Operating_System
(	O
OSF/1	B-Operating_System
Release	O
1.0	O
)	O
in	O
January	O
1992	O
was	O
for	O
its	O
line	O
of	O
MIPS-based	O
DECstation	B-Device
workstations	O
,	O
however	O
this	O
was	O
never	O
a	O
fully	O
supported	O
product	O
.	O
</s>
<s>
DEC	O
ported	O
OSF/1	B-Operating_System
to	O
their	O
new	O
Alpha	B-Device
AXP	I-Device
platform	O
as	O
DEC	B-Operating_System
OSF/1	I-Operating_System
AXP	I-Operating_System
Release	O
1.2	O
,	O
released	O
in	O
March	O
1993	O
.	O
</s>
<s>
OSF/1	B-Operating_System
AXP	I-Operating_System
is	O
a	O
full	O
64-bit	B-Device
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
After	O
OSF/1	B-Operating_System
AXP	I-Operating_System
V2.0	O
onwards	O
,	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
compatibility	O
was	O
also	O
integrated	O
into	O
the	O
system	O
.	O
</s>
<s>
OSF/1	B-Operating_System
v2	O
was	O
also	O
released	O
for	O
DECStation	B-Device
MIPS	B-Device
systems	O
the	O
same	O
year	O
.	O
</s>
<s>
Subsequent	O
releases	O
are	O
named	O
Digital	B-Operating_System
UNIX	I-Operating_System
,	O
and	O
later	O
,	O
Tru64	B-Operating_System
UNIX	I-Operating_System
.	O
</s>
<s>
HP	O
also	O
released	O
a	O
port	O
of	O
OSF/1	B-Operating_System
to	O
the	O
early	O
HP	O
9000/700	O
workstations	O
based	O
on	O
the	O
PA-RISC	B-Device
1.1	O
architecture	O
.	O
</s>
<s>
This	O
was	O
withdrawn	O
soon	O
afterwards	O
due	O
to	O
lack	O
of	O
software	O
and	O
hardware	O
support	O
compared	O
to	O
competing	O
operating	B-General_Concept
systems	I-General_Concept
,	O
specifically	O
HP-UX	B-Application
.	O
</s>
<s>
As	O
part	O
of	O
the	O
AIM	O
alliance	O
and	O
the	O
resulting	O
PowerOpen	B-Application
specification	O
,	O
Apple	O
Computer	O
intended	O
to	O
base	O
A/UX	B-Operating_System
4.0	I-Operating_System
for	O
its	O
PowerPC-based	O
Macintoshes	B-Device
upon	O
OSF/1	B-Operating_System
,	O
but	O
the	O
project	O
was	O
cancelled	O
and	O
PowerOpen	B-Application
deprecated	O
.	O
</s>
<s>
IBM	O
used	O
OSF/1	B-Operating_System
as	O
the	O
basis	O
of	O
the	O
AIX/ESA	O
operating	B-General_Concept
system	I-General_Concept
for	O
System/370	B-Device
and	O
System/390	B-Device
mainframes	O
.	O
</s>
<s>
OSF/1	B-Operating_System
was	O
also	O
ported	O
by	O
Kendall	O
Square	O
Research	O
to	O
its	O
proprietary	O
microarchitecture	B-General_Concept
used	O
in	O
the	O
KSR1	O
supercomputer	B-Architecture
.	O
</s>
<s>
The	O
Open	B-Application
Software	I-Application
Foundation	I-Application
created	O
OSFMK	O
which	O
is	O
a	O
commercial	O
version	O
of	O
the	O
Mach	B-Operating_System
kernel	I-Operating_System
for	O
use	O
in	O
OSF/1	B-Operating_System
.	O
</s>
<s>
It	O
contains	O
applicable	O
code	O
from	O
the	O
University	O
of	O
Utah	O
Mach	B-Operating_System
4	O
kernel	O
(	O
such	O
as	O
the	O
"	O
Shuttles	O
"	O
modification	O
used	O
to	O
speed	O
up	O
message	O
passing	O
)	O
and	O
applicable	O
code	O
from	O
the	O
many	O
Mach	B-Operating_System
3.0	I-Operating_System
variants	O
that	O
sprouted	O
off	O
from	O
the	O
original	O
Carnegie	O
Mellon	O
University	O
Mach	B-Operating_System
3.0	I-Operating_System
kernel	O
.	O
</s>
<s>
It	O
also	O
consists	O
of	O
improvements	O
made	O
by	O
the	O
OSF	O
such	O
as	O
built-in	O
collocation	O
capability	O
,	O
realtime	O
improvements	O
,	O
and	O
rewriting	O
of	O
the	O
IPC	B-Operating_System
RPC	B-Operating_System
component	O
for	O
better	O
performance	O
.	O
</s>
<s>
OSF/1	B-Operating_System
AD	O
(	O
Advanced	O
Development	O
)	O
was	O
a	O
distributed	B-Operating_System
version	O
of	O
OSF/1	B-Operating_System
developed	O
for	O
massively	B-Operating_System
parallel	I-Operating_System
supercomputers	B-Architecture
by	O
Locus	O
Computing	O
Corporation	O
.	O
</s>
<s>
Variants	O
of	O
OSF/1	B-Operating_System
AD	O
are	O
on	O
several	O
such	O
systems	O
,	O
including	O
the	O
Intel	B-Device
Paragon	I-Device
XP/S	O
and	O
ASCI	B-Device
Red	I-Device
,	O
Convex	O
Exemplar	O
SPP-1200	O
(	O
as	O
SPP-UX	O
)	O
and	O
the	O
Hitachi	O
SR2201	O
(	O
as	O
HI-UX	O
MPP	O
)	O
.	O
</s>
