<s>
Inferno	B-Operating_System
is	O
a	O
distributed	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
started	O
at	O
Bell	O
Labs	O
and	O
now	O
developed	O
and	O
maintained	O
by	O
Vita	O
Nuova	O
Holdings	O
as	O
free	B-Application
software	I-Application
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
Inferno	B-Operating_System
was	O
based	O
on	O
the	O
experience	O
gained	O
with	O
Plan	B-Operating_System
9	I-Operating_System
from	I-Operating_System
Bell	I-Operating_System
Labs	I-Operating_System
,	O
and	O
the	O
further	O
research	O
of	O
Bell	O
Labs	O
into	O
operating	O
systems	O
,	O
languages	O
,	O
on-the-fly	O
compilers	O
,	O
graphics	O
,	O
security	O
,	O
networking	O
and	O
portability	O
.	O
</s>
<s>
In	O
Italian	O
,	O
Inferno	B-Operating_System
means	O
"	O
hell	O
"	O
,	O
of	O
which	O
there	O
are	O
nine	O
circles	O
in	O
Dante	O
's	O
Divine	O
Comedy	O
.	O
</s>
<s>
Inferno	B-Operating_System
was	O
created	O
in	O
1995	O
by	O
members	O
of	O
Bell	O
Labs	O
 '	O
Computer	O
Science	O
Research	O
division	O
to	O
bring	O
ideas	O
derived	O
from	O
their	O
previous	O
operating	O
system	O
,	O
Plan	B-Operating_System
9	I-Operating_System
from	I-Operating_System
Bell	I-Operating_System
Labs	I-Operating_System
,	O
to	O
a	O
wider	O
range	O
of	O
devices	O
and	O
networks	O
.	O
</s>
<s>
Inferno	B-Operating_System
is	O
a	O
distributed	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
based	O
on	O
three	O
basic	O
principles	O
:	O
</s>
<s>
To	O
handle	O
the	O
diversity	O
of	O
network	O
environments	O
it	O
was	O
intended	O
to	O
be	O
used	O
in	O
,	O
the	O
designers	O
decided	O
a	O
virtual	B-Architecture
machine	I-Architecture
(	O
VM	O
)	O
was	O
a	O
necessary	O
component	O
of	O
the	O
system	O
.	O
</s>
<s>
This	O
is	O
the	O
same	O
conclusion	O
of	O
the	O
Oak	O
project	O
that	O
became	O
Java	B-Language
,	O
but	O
arrived	O
at	O
independently	O
.	O
</s>
<s>
The	O
Dis	B-Application
virtual	B-Architecture
machine	I-Architecture
is	O
a	O
register	B-Application
machine	I-Application
intended	O
to	O
closely	O
match	O
the	O
architecture	O
it	O
runs	O
on	O
,	O
in	O
contrast	O
to	O
the	O
stack	B-Application
machine	I-Application
of	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
.	O
</s>
<s>
The	O
virtual	B-Architecture
machine	I-Architecture
provides	O
memory	O
management	O
designed	O
to	O
be	O
efficient	O
on	O
devices	O
with	O
as	O
little	O
as	O
1	O
MiB	O
of	O
memory	O
and	O
without	O
memory-mapping	B-Architecture
hardware	O
.	O
</s>
<s>
Its	O
garbage	B-General_Concept
collector	I-General_Concept
is	O
a	O
hybrid	O
of	O
reference	O
counting	O
and	O
a	O
real-time	O
coloring	O
collector	O
that	O
gathers	O
cyclic	O
data	O
.	O
</s>
<s>
The	O
Inferno	B-Operating_System
kernel	I-Operating_System
contains	O
the	O
virtual	B-Architecture
machine	I-Architecture
,	O
on-the-fly	O
compiler	O
,	O
scheduler	O
,	O
devices	O
,	O
protocol	O
stacks	O
,	O
and	O
the	O
name	O
space	O
evaluator	O
for	O
each	O
process	O
 '	O
file	O
name	O
space	O
,	O
and	O
the	O
root	O
of	O
the	O
file	O
system	O
hierarchy	O
.	O
</s>
<s>
The	O
kernel	O
also	O
includes	O
some	O
built-in	O
modules	O
that	O
provide	O
interfaces	O
of	O
the	O
virtual	B-Architecture
operating	I-Architecture
system	I-Architecture
,	O
such	O
as	O
system	O
calls	O
,	O
graphics	O
,	O
security	O
,	O
and	O
math	O
modules	O
.	O
</s>
<s>
The	O
Bell	O
Labs	O
Technical	O
Journal	O
paper	O
introducing	O
Inferno	B-Operating_System
listed	O
several	O
dimensions	O
of	O
portability	O
and	O
versatility	O
provided	O
by	O
the	O
OS	O
:	O
</s>
<s>
Portability	O
across	O
processors	O
:	O
it	O
currently	O
runs	O
on	O
ARM	B-Architecture
,	O
SGI	O
MIPS	B-Device
,	O
HP	B-Device
PA-RISC	I-Device
,	O
IBM	B-Architecture
PowerPC	I-Architecture
,	O
Sun	B-Architecture
SPARC	I-Architecture
,	O
and	O
Intel	B-Operating_System
x86	I-Operating_System
architectures	O
and	O
is	O
readily	O
portable	O
to	O
others	O
.	O
</s>
<s>
Portability	O
across	O
environments	O
:	O
it	O
runs	O
as	O
a	O
stand-alone	O
operating	O
system	O
on	O
small	O
terminals	O
,	O
and	O
also	O
as	O
a	O
user	O
application	O
under	O
Bell	O
Plan	B-Operating_System
9	I-Operating_System
,	O
MS	B-Device
Windows	I-Device
NT	I-Device
,	O
Windows	B-Application
95	I-Application
,	O
and	O
Unix	B-Application
(	O
SGI	B-Operating_System
Irix	I-Operating_System
,	O
Sun	B-Application
Solaris	I-Application
,	O
FreeBSD	B-Operating_System
,	O
Apple	B-Operating_System
Mac	I-Operating_System
OS	I-Operating_System
X	I-Operating_System
,	O
Linux	B-Application
,	O
IBM	B-Application
AIX	I-Application
,	O
HP-UX	B-Application
,	O
Digital	O
Tru64	B-Operating_System
)	O
.	O
</s>
<s>
In	O
all	O
of	O
these	O
environments	O
,	O
Inferno	B-Operating_System
programs	O
see	O
an	O
identical	O
interface	O
.	O
</s>
<s>
Distributed	O
design	O
:	O
the	O
identical	O
environment	O
is	O
established	O
at	O
the	O
user	O
's	O
terminal	O
and	O
at	O
the	O
server	O
,	O
and	O
each	O
may	O
import	O
the	O
resources	B-General_Concept
(	O
for	O
example	O
,	O
the	O
attached	O
I/O	O
devices	O
or	O
networks	O
)	O
of	O
the	O
other	O
.	O
</s>
<s>
Minimal	O
hardware	O
requirements	O
:	O
it	O
runs	O
useful	O
applications	O
stand-alone	O
on	O
machines	O
with	O
as	O
little	O
as	O
1	O
MiB	O
of	O
memory	O
,	O
and	O
does	O
not	O
require	O
memory-mapping	B-Architecture
hardware	O
.	O
</s>
<s>
Portable	O
programs	O
:	O
Inferno	B-Operating_System
programs	O
are	O
written	O
in	O
the	O
type-safe	B-Language
language	I-Language
Limbo	B-Application
and	O
compiled	O
to	O
Dis	B-Application
bytecode	O
,	O
which	O
can	O
be	O
run	O
without	O
modifications	O
on	O
all	O
Inferno	B-Operating_System
platforms	O
.	O
</s>
<s>
Dynamic	O
adaptability	O
:	O
programs	O
may	O
,	O
depending	O
on	O
the	O
hardware	O
or	O
other	O
resources	B-General_Concept
available	O
,	O
load	O
different	O
program	O
modules	O
to	O
perform	O
a	O
specific	O
function	O
.	O
</s>
<s>
Inferno	B-Operating_System
programs	O
are	O
portable	O
across	O
a	O
broad	O
mix	O
of	O
hardware	O
,	O
networks	O
,	O
and	O
environments	O
.	O
</s>
<s>
A	O
communications	O
protocol	O
called	O
Styx	B-Operating_System
is	O
applied	O
uniformly	O
to	O
access	O
both	O
local	O
and	O
remote	O
resources	B-General_Concept
,	O
which	O
programs	O
use	O
by	O
calling	O
standard	O
file	O
operations	O
,	O
open	O
,	O
read	O
,	O
write	O
,	O
and	O
close	O
.	O
</s>
<s>
As	O
of	O
the	O
fourth	O
edition	O
of	O
Inferno	B-Operating_System
,	O
Styx	B-Operating_System
is	O
identical	O
to	O
Plan	B-Operating_System
9	I-Operating_System
's	O
newer	O
version	O
of	O
its	O
hallmark	O
9P	B-Operating_System
protocol	O
,	O
9P2000	B-Operating_System
.	O
</s>
<s>
Most	O
of	O
the	O
Inferno	B-Operating_System
commands	O
are	O
very	O
similar	O
to	O
Unix	B-Application
commands	I-Application
with	O
the	O
same	O
name	O
.	O
</s>
<s>
Inferno	B-Operating_System
is	O
a	O
descendant	O
of	O
Plan	B-Operating_System
9	I-Operating_System
from	I-Operating_System
Bell	I-Operating_System
Labs	I-Operating_System
,	O
and	O
shares	O
many	O
design	O
concepts	O
and	O
even	O
source	O
code	O
in	O
the	O
kernel	O
,	O
particularly	O
around	O
devices	O
and	O
the	O
Styx/9P2000	O
protocol	O
.	O
</s>
<s>
Inferno	B-Operating_System
shares	O
with	O
Plan	B-Operating_System
9	I-Operating_System
the	O
Unix	B-Application
heritage	O
from	O
Bell	O
Labs	O
and	O
the	B-Operating_System
Unix	I-Operating_System
philosophy	I-Operating_System
.	O
</s>
<s>
Many	O
of	O
the	O
command	O
line	O
tools	O
in	O
Inferno	B-Operating_System
were	O
Plan	B-Operating_System
9	I-Operating_System
tools	O
that	O
were	O
translated	O
to	O
Limbo	B-Application
.	O
</s>
<s>
In	O
the	O
mid-1990s	O
,	O
Plan	B-Operating_System
9	I-Operating_System
development	O
was	O
set	O
aside	O
in	O
favor	O
of	O
Inferno	B-Operating_System
.	O
</s>
<s>
The	O
new	O
system	O
's	O
existence	O
was	O
leaked	O
by	O
Dennis	O
Ritchie	O
in	O
early	O
1996	O
,	O
after	O
less	O
than	O
a	O
year	O
of	O
development	O
on	O
the	O
system	O
,	O
and	O
publicly	O
presented	O
later	O
that	O
year	O
as	O
a	O
competitor	O
to	O
Java	B-Language
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
Bell	O
Labs	O
 '	O
parent	O
company	O
AT&T	O
licensed	O
Java	B-Language
technology	I-Language
from	O
Sun	O
Microsystems	O
.	O
</s>
<s>
In	O
March	O
–	O
April	O
1997	O
IEEE	O
Internet	O
Computing	O
included	O
an	O
advertisement	O
for	O
Inferno	B-Operating_System
networking	O
software	O
.	O
</s>
<s>
The	O
advertisement	O
stated	O
that	O
video	O
games	O
could	O
talk	O
to	O
computers	O
,	O
–	O
a	O
PlayStation	B-Device
was	O
pictured	O
–	O
cell	O
phones	O
could	O
access	O
email	O
and	O
voice	O
mail	O
was	O
available	O
via	O
TV	O
.	O
</s>
<s>
Lucent	O
used	O
Inferno	B-Operating_System
in	O
at	O
least	O
two	O
internal	O
products	O
:	O
the	O
Lucent	O
VPN	O
Firewall	O
Brick	O
,	O
and	O
the	O
Lucent	O
Pathstar	O
phone	O
switch	O
.	O
</s>
<s>
They	O
initially	O
tried	O
to	O
sell	O
source	O
code	O
licenses	O
of	O
Inferno	B-Operating_System
but	O
found	O
few	O
buyers	O
.	O
</s>
<s>
Lucent	O
did	O
little	O
marketing	O
and	O
missed	O
the	O
importance	O
of	O
the	O
Internet	O
and	O
Inferno	B-Operating_System
's	O
relation	O
to	O
it	O
.	O
</s>
<s>
During	O
the	O
same	O
time	O
Sun	O
Microsystems	O
was	O
heavily	O
marketing	O
its	O
own	O
Java	B-Language
programming	I-Language
language	I-Language
,	O
which	O
was	O
targeting	O
a	O
similar	O
market	O
,	O
with	O
analogous	O
technology	O
,	O
that	O
worked	O
in	O
web	B-Application
browsers	I-Application
and	O
also	O
filled	O
the	O
demand	O
for	O
object-oriented	B-Language
languages	I-Language
popular	O
at	O
that	O
time	O
.	O
</s>
<s>
Lucent	O
licensed	O
Java	B-Language
from	O
Sun	O
,	O
claiming	O
that	O
all	O
Inferno	B-Operating_System
devices	O
would	O
be	O
made	O
to	O
run	O
Java	B-Language
.	O
</s>
<s>
A	O
Java	B-Language
byte	O
code	O
to	O
Dis	B-Application
byte	O
code	O
translator	O
was	O
written	O
to	O
facilitate	O
that	O
.	O
</s>
<s>
However	O
,	O
Inferno	B-Operating_System
still	O
did	O
not	O
find	O
customers	O
.	O
</s>
<s>
The	O
Inferno	B-Operating_System
Business	O
Unit	O
closed	O
after	O
three	O
years	O
,	O
and	O
was	O
sold	O
to	O
Vita	O
Nuova	O
Holdings	O
.	O
</s>
<s>
Vita	O
Nuova	O
continued	O
development	O
and	O
offered	O
commercial	O
licenses	O
to	O
the	O
complete	O
system	O
,	O
and	O
free	O
downloads	O
and	O
licenses	O
(	O
not	O
GPL	B-License
compatible	O
)	O
for	O
all	O
of	O
the	O
system	O
except	O
the	O
kernel	O
and	O
VM	O
.	O
</s>
<s>
Eventually	O
,	O
Vita	O
Nuova	O
released	O
the	O
4th	O
edition	O
under	O
more	O
common	O
free	B-License
software	I-License
licenses	I-License
,	O
and	O
in	O
2021	O
they	O
relicensed	O
all	O
editions	O
under	O
mainly	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
+	O
Release	O
timeline	O
Date	O
Release	O
Comment	O
1996	O
Inferno	B-Operating_System
Beta	O
Released	O
by	O
Bell	O
Labs	O
May	O
1997	O
Inferno	B-Operating_System
Release	O
1.0	O
Winter	O
1997	O
Bell	O
Labs	O
Technical	O
Journal	O
Article	O
July	O
1999	O
Inferno	B-Operating_System
2nd	O
Edition	O
Released	O
by	O
Lucent	O
's	O
Inferno	B-Operating_System
Business	O
Unit	O
June	O
2001	O
Inferno	B-Operating_System
3rd	O
Edition	O
Released	O
by	O
Vita	O
Nuova	O
2004	O
Inferno	B-Operating_System
4th	O
Edition	O
Open	O
Source	O
release	O
;	O
changes	O
to	O
many	O
interfaces	O
(	O
incompatible	O
with	O
earlier	O
editions	O
)	O
;	O
includes	O
support	O
for	O
9P2000	B-Operating_System
.	O
</s>
<s>
Inferno	B-Operating_System
runs	O
on	O
native	O
hardware	O
directly	O
and	O
also	O
as	O
an	O
application	O
providing	O
a	O
virtual	B-Architecture
operating	I-Architecture
system	I-Architecture
which	O
runs	O
on	O
other	O
platforms	O
.	O
</s>
<s>
Programs	O
can	O
be	O
developed	O
and	O
run	O
on	O
all	O
Inferno	B-Operating_System
platforms	O
without	O
modifying	O
or	O
recompiling	O
.	O
</s>
<s>
Native	O
ports	O
include	O
these	O
architectures	O
:	O
x86	B-Operating_System
,	O
MIPS	B-Device
,	O
ARM	B-Architecture
,	O
PowerPC	B-Architecture
,	O
SPARC	B-Architecture
.	O
</s>
<s>
Hosted	O
or	O
virtual	O
OS	O
ports	O
include	O
:	O
Microsoft	B-Application
Windows	I-Application
,	O
Linux	B-Application
,	O
FreeBSD	B-Operating_System
,	O
Plan	B-Operating_System
9	I-Operating_System
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
,	O
Solaris	B-Application
,	O
IRIX	B-Operating_System
,	O
UnixWare	B-Operating_System
.	O
</s>
<s>
Inferno	B-Operating_System
can	O
also	O
be	O
hosted	O
by	O
a	O
plugin	B-Application
to	O
Internet	B-Application
Explorer	I-Application
.	O
</s>
<s>
Vita	O
Nuova	O
said	O
that	O
plugins	B-Application
for	O
other	O
browsers	B-Application
were	O
under	O
development	O
,	O
but	O
they	O
were	O
never	O
released	O
.	O
</s>
<s>
Inferno	B-Operating_System
has	O
also	O
been	O
ported	O
to	O
Openmoko	B-Application
,	O
Nintendo	B-Device
DS	I-Device
,	O
SheevaPlug	B-Application
,	O
and	O
Android	B-Application
.	O
</s>
<s>
Inferno	B-Operating_System
4th	O
edition	O
was	O
released	O
in	O
early	O
2005	O
as	O
free	B-Application
software	I-Application
.	O
</s>
<s>
Specifically	O
,	O
it	O
was	O
dual-licensed	B-License
under	O
two	O
structures	O
.	O
</s>
<s>
Users	O
could	O
either	O
obtain	O
it	O
under	O
a	O
set	O
of	O
free	B-License
software	I-License
licenses	I-License
,	O
or	O
they	O
could	O
obtain	O
it	O
under	O
a	O
proprietary	B-Application
license	I-Application
.	O
</s>
<s>
In	O
the	O
case	O
of	O
the	O
free	B-License
software	I-License
license	I-License
scheme	O
,	O
different	O
parts	O
of	O
the	O
system	O
were	O
covered	O
by	O
different	O
licenses	O
,	O
including	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
the	O
GNU	B-Application
Lesser	I-Application
General	I-Application
Public	I-Application
License	I-Application
,	O
the	O
Lucent	B-License
Public	I-License
License	I-License
,	O
and	O
the	B-License
MIT	I-License
License	I-License
,	O
excluding	O
the	O
fonts	O
,	O
which	O
are	O
sub-licensed	O
from	O
Bigelow	O
and	O
Holmes	O
.	O
</s>
<s>
In	O
March	O
2021	O
,	O
all	O
editions	O
were	O
relicensed	O
under	O
mainly	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
