<s>
Ancient	B-Operating_System
UNIX	I-Operating_System
is	O
any	O
early	O
release	O
of	O
the	O
Unix	B-Application
code	B-General_Concept
base	I-General_Concept
prior	O
to	O
Unix	B-Operating_System
System	I-Operating_System
III	I-Operating_System
,	O
particularly	O
the	O
Research	B-Operating_System
Unix	I-Operating_System
releases	O
prior	O
to	O
and	O
including	O
Version	B-Operating_System
7	I-Operating_System
(	O
the	O
base	O
for	O
UNIX/32V	B-Operating_System
as	O
well	O
as	O
later	O
developments	O
of	O
AT&T	B-Operating_System
Unix	I-Operating_System
)	O
.	O
</s>
<s>
After	O
the	O
publication	O
of	O
the	O
Lions	O
 '	O
book	O
,	O
work	O
was	O
undertaken	O
to	O
release	O
earlier	O
versions	O
of	O
the	O
codebase	B-General_Concept
.	O
</s>
<s>
Later	O
,	O
in	O
January	O
2002	O
,	O
Caldera	O
International	O
(	O
now	O
SCO	O
Group	O
)	O
relicensed	O
(	O
but	O
has	O
not	O
made	O
available	O
)	O
several	O
versions	O
under	O
the	O
four-clause	O
BSD	B-Operating_System
license	I-Operating_System
,	O
namely	O
:	O
</s>
<s>
,	O
there	O
has	O
been	O
no	O
widespread	O
use	O
of	O
the	O
code	O
,	O
but	O
it	O
can	O
be	O
used	O
on	O
emulator	B-Application
systems	O
,	O
and	O
Version	B-Operating_System
5	I-Operating_System
Unix	I-Operating_System
runs	O
on	O
the	O
Nintendo	B-Device
Game	I-Device
Boy	I-Device
Advance	I-Device
using	O
the	O
SIMH	B-Application
PDP-11	B-Device
emulator	B-Application
.	O
</s>
<s>
Version	B-Operating_System
6	I-Operating_System
Unix	I-Operating_System
provides	O
the	O
basis	O
for	O
the	O
MIT	O
xv6	B-Operating_System
teaching	O
system	O
,	O
which	O
is	O
an	O
update	O
of	O
that	O
version	O
to	O
ANSI	O
C	O
and	O
the	O
x86	O
or	O
RISC-V	O
platform	O
.	O
</s>
<s>
The	O
BSD	B-Operating_System
vi	B-Application
text	B-Application
editor	I-Application
is	O
based	O
on	O
code	O
from	O
the	O
ed	B-Application
line	O
editor	O
in	O
those	O
early	O
Unixes	B-Application
.	O
</s>
<s>
Therefore	O
,	O
"	O
traditional	O
"	O
vi	B-Application
could	O
not	O
be	O
distributed	O
freely	O
,	O
and	O
various	O
work-alikes	O
(	O
such	O
as	O
nvi	B-Device
)	O
were	O
created	O
.	O
</s>
<s>
Now	O
that	O
the	O
original	O
code	O
is	O
no	O
longer	O
encumbered	O
,	O
the	O
"	O
traditional	O
"	O
vi	B-Application
has	O
been	O
adapted	O
for	O
modern	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
As	O
a	O
result	O
of	O
the	O
SCO	O
Group	O
,	O
Inc	O
.	O
v	O
.	O
Novell	O
,	O
Inc	O
.	O
case	O
,	O
Novell	O
,	O
Inc	O
.	O
was	O
found	O
to	O
not	O
have	O
transferred	O
the	O
copyrights	O
of	O
UNIX	B-Application
to	O
SCO	O
Group	O
,	O
Inc	O
.	O
</s>
<s>
First	O
edition	O
Unix	B-Application
was	O
restored	O
to	O
a	O
usable	O
state	O
by	O
a	O
restoration	O
team	O
from	O
the	O
Unix	B-Application
Heritage	O
Society	O
in	O
2008	O
.	O
</s>
<s>
The	O
restoration	O
process	O
started	O
with	O
paper	O
listings	O
of	O
the	O
source	O
code	O
which	O
were	O
in	O
Unix	B-Application
PDP-11	B-Device
assembly	O
language	O
.	O
</s>
