<s>
Genode	B-Language
is	O
a	O
free	B-License
and	I-License
open-source	I-License
software	I-License
operating	B-General_Concept
system	I-General_Concept
(	O
OS	O
)	O
framework	O
consisting	O
of	O
a	O
microkernel	B-Operating_System
abstraction	O
layer	O
and	O
a	O
set	O
of	O
user	B-Operating_System
space	I-Operating_System
components	O
.	O
</s>
<s>
The	O
framework	O
is	O
notable	O
as	O
one	O
of	O
the	O
few	O
open-source	B-Application
operating	B-General_Concept
systems	I-General_Concept
not	O
derived	O
from	O
a	O
proprietary	O
OS	O
,	O
such	O
as	O
Unix	B-Application
.	O
</s>
<s>
Genode	B-Language
can	O
be	O
used	O
as	O
a	O
basis	O
for	O
a	O
desktop	B-Device
computer	I-Device
or	O
tablet	O
OS	O
or	O
as	O
a	O
virtual	B-Operating_System
machine	I-Operating_System
monitor	I-Operating_System
for	O
guest	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
framework	O
has	O
been	O
used	O
as	O
a	O
trusted	O
component	O
of	O
secure	O
virtualization	B-General_Concept
systems	O
for	O
both	O
x86	B-General_Concept
and	O
ARM	B-Architecture
.	O
</s>
<s>
The	O
small	O
codebase	B-General_Concept
of	O
Genode	B-Language
makes	O
it	O
a	O
flexible	O
alternative	O
to	O
more	O
complex	O
Unix-derived	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
For	O
this	O
reason	O
the	O
framework	O
has	O
been	O
used	O
as	O
a	O
base	O
system	O
for	O
research	O
in	O
such	O
fields	O
as	O
virtualization	B-General_Concept
,	O
inter-process	B-Operating_System
communication	I-Operating_System
,	O
IP	B-Protocol
stack	I-Protocol
isolation	O
,	O
monitoring	O
,	O
and	O
software	O
development	O
.	O
</s>
<s>
Genode	B-Language
was	O
first	O
conceived	O
as	O
the	O
Bastei	O
OS	O
Architecture	O
research	O
report	O
at	O
the	O
Technical	O
University	O
of	O
Dresden	O
(	O
TU	O
Dresden	O
)	O
.	O
</s>
<s>
This	O
report	O
was	O
motivated	O
in	O
part	O
by	O
research	O
into	O
L4	B-Operating_System
microhypervisors	O
conducted	O
during	O
the	O
same	O
time	O
.	O
</s>
<s>
Following	O
the	O
success	O
of	O
an	O
early	O
prototype	O
,	O
the	O
authors	O
of	O
the	O
report	O
founded	O
the	O
company	O
Genode	B-Language
Labs	O
to	O
develop	O
Bastei	O
as	O
the	O
Genode	B-Language
OS	O
Framework	O
.	O
</s>
<s>
The	O
project	O
is	O
developed	O
publicly	O
as	O
an	O
open	B-Application
source	I-Application
project	O
released	O
under	O
the	O
terms	O
of	O
the	O
GNU	B-Application
Affero	I-Application
General	I-Application
Public	I-Application
License	I-Application
with	O
a	O
commercial	O
entity	O
offering	O
alternative	O
licensing	O
.	O
</s>
<s>
Releases	O
are	O
scheduled	O
at	O
three-month	O
intervals	O
to	O
make	O
changes	O
to	O
the	O
system	O
application	B-Operating_System
binary	I-Operating_System
interface	I-Operating_System
(	O
ABI	O
)	O
,	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
,	O
and	O
issue	O
documentation	O
.	O
</s>
<s>
Genode	B-Language
builds	O
on	O
the	O
general	O
philosophy	O
of	O
microkernels	B-Operating_System
:	O
the	O
smaller	O
and	O
simpler	O
the	O
code	O
,	O
the	O
easier	O
it	O
is	O
to	O
verify	O
for	O
trustworthiness	O
and	O
correctness	O
.	O
</s>
<s>
Genode	B-Language
extends	O
this	O
philosophy	O
to	O
user	B-Operating_System
space	I-Operating_System
by	O
composing	O
complex	O
applications	O
from	O
small	O
components	O
.	O
</s>
<s>
Any	O
component	O
acting	O
as	O
a	O
parent	O
may	O
apply	O
resource	O
and	O
inter-process	B-Operating_System
communication	I-Operating_System
(	O
IPC	O
)	O
access	O
policies	O
to	O
its	O
children	O
.	O
</s>
<s>
This	O
hierarchical	O
system	O
layout	O
yields	O
intuitive	O
partitioning	O
and	O
privilege	O
deescalation	O
as	O
specialized	O
subsystems	O
are	O
nested	O
within	O
more	O
general	O
subsystems	O
,	O
mitigating	O
the	O
confused	O
deputy	O
problem	O
endemic	O
to	O
centralized	O
or	O
superuser	B-Application
system	O
policy	O
.	O
</s>
<s>
The	O
framework	O
is	O
designed	O
to	O
be	O
hosted	O
by	O
microkernels	B-Operating_System
,	O
however	O
the	O
features	O
of	O
any	O
given	O
microkernel	B-Operating_System
fall	O
mostly	O
within	O
a	O
common	O
set	O
,	O
and	O
monolithic	B-Operating_System
kernels	I-Operating_System
implement	O
a	O
superset	O
of	O
those	O
features	O
.	O
</s>
<s>
Abstracting	O
these	O
features	O
allows	O
Genode	B-Language
to	O
act	O
as	O
user	B-Operating_System
space	I-Operating_System
for	O
a	O
variety	O
of	O
L4	B-Operating_System
microkernels	I-Operating_System
,	O
and	O
Linux	O
.	O
</s>
<s>
Genode	B-Language
is	O
often	O
criticized	O
for	O
the	O
choice	O
of	O
its	O
implementation	O
language	O
,	O
C++	B-Language
(	O
a	O
few	O
other	O
operating	B-General_Concept
systems	I-General_Concept
implemented	O
in	O
C++	B-Language
include	O
BeOS	B-Application
,	O
Fuchsia	B-Language
,	O
Ghost	B-Language
,	O
Haiku	B-Language
,	O
IncludeOS	B-Language
,	O
OSv	B-Language
,	O
Palm	B-Operating_System
OS	I-Operating_System
,	O
ReactOS	B-Application
,	O
Syllable	B-Application
,	O
and	O
Symbian	B-Operating_System
)	O
.	O
</s>
<s>
This	O
critique	O
usually	O
asserts	O
that	O
C++	B-Language
is	O
a	O
poor	O
choice	O
for	O
implementing	O
system	O
libraries	O
and	O
APIs	B-Application
because	O
of	O
the	O
inherent	O
complexity	O
of	O
C++	B-Language
and	O
the	O
difficulty	O
in	O
analyzing	O
code	O
for	O
correct	O
behavior	O
.	O
</s>
<s>
While	O
Genode	B-Language
does	O
make	O
use	O
of	O
multiple	O
inheritance	O
and	O
templates	O
in	O
its	O
system	O
library	O
,	O
the	O
use	O
of	O
the	O
C++	B-Language
Standard	I-Language
Library	I-Language
is	O
not	O
allowed	O
and	O
language	O
features	O
that	O
rely	O
on	O
implicit	O
global	O
state	O
,	O
such	O
as	O
thread-local	O
storage	O
and	O
the	O
global	O
allocator	O
,	O
have	O
been	O
removed	O
from	O
the	O
language	O
runtime	O
.	O
</s>
<s>
Comprehensive	O
static	O
analysis	O
of	O
C++	B-Language
is	O
not	O
possible	O
.	O
</s>
<s>
However	O
,	O
the	O
Genode	B-Language
project	O
publishes	O
unit	O
tests	O
for	O
empirical	O
analysis	O
.	O
</s>
<s>
Genode	B-Language
components	O
consume	O
and	O
publish	O
state	O
using	O
structured	O
data	O
serialized	O
in	O
XML	B-Protocol
,	O
in	O
contrast	O
to	O
the	O
plain	O
text	O
model	O
of	O
Unix	B-Application
derivatives	O
.	O
</s>
<s>
The	O
Genode	B-Language
framework	O
makes	O
use	O
of	O
XML	B-Protocol
in	O
effectively	O
all	O
of	O
its	O
components	O
because	O
XML	B-Protocol
is	O
easily	O
parsed	O
and	O
generated	O
programmatically	O
while	O
still	O
being	O
possible	O
to	O
understand	O
and	O
edit	O
manually	O
.	O
</s>
<s>
Genode	B-Language
lacks	O
any	O
practical	O
global	O
namespace	O
;	O
there	O
is	O
no	O
global	O
file	B-Application
system	I-Application
or	O
registry	O
of	O
processes	B-Operating_System
or	O
IPC	O
endpoints	O
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
to	O
systems	O
such	O
as	O
Unix	B-Application
which	O
feature	O
a	O
ubiquitous	O
file	B-Application
system	I-Application
and	O
allow	O
a	O
superuser	B-Application
context	O
to	O
arbitrarily	O
manage	O
any	O
process	O
within	O
the	O
system	O
.	O
</s>
<s>
Explicitly	O
declaring	O
the	O
permissions	O
and	O
routing	O
of	O
components	O
may	O
be	O
perceived	O
as	O
labor-intensive	O
relative	O
to	O
Unix	B-Application
.	O
</s>
<s>
However	O
,	O
compartmentalizing	O
administration	O
allows	O
subsystems	O
to	O
be	O
managed	O
by	O
mutually	O
untrusted	O
system	B-Application
administrators	I-Application
on	O
the	O
same	O
machine	O
without	O
resorting	O
to	O
virtualizing	O
,	O
a	O
common	O
isolation	O
method	O
.	O
</s>
<s>
The	O
Genode	B-Language
project	O
publishes	O
a	O
desktop	B-General_Concept
operating	I-General_Concept
system	I-General_Concept
named	O
Sculpt	O
that	O
targets	O
contemporary	O
consumer	O
laptops	B-Device
.	O
</s>
<s>
Sculpt	O
is	O
a	O
small	O
base	O
system	O
with	O
automatic	O
device	O
detection	O
and	O
configuration	O
,	O
some	O
GUI	O
control	O
interfaces	O
,	O
and	O
frontends	O
to	O
the	O
Genode	B-Language
package	O
manager	O
.	O
</s>
<s>
The	O
system	O
does	O
not	O
feature	O
a	O
full	O
desktop	O
environment	O
,	O
but	O
requires	O
users	O
to	O
deploy	O
virtual	B-Architecture
machines	I-Architecture
hosting	O
traditional	O
OSes	O
for	O
a	O
fully	O
featured	O
desktop	O
.	O
</s>
<s>
Sculpt	O
is	O
distinguished	O
from	O
the	O
Genode	B-Language
operating	B-General_Concept
system	I-General_Concept
framework	O
in	O
that	O
it	O
relies	O
heavily	O
on	O
dynamic	O
reconfiguration	O
using	O
privileged	O
control	O
components	O
in	O
contrast	O
to	O
specialized	O
systems	O
with	O
static	O
policies	O
.	O
</s>
