<s>
GNU	B-Application
Guix	I-Application
System	I-Application
or	O
Guix	B-Application
System	O
(	O
previously	O
GuixSD	B-Application
)	O
is	O
a	O
rolling	O
release	O
,	O
free	B-Application
and	I-Application
open	I-Application
source	I-Application
Linux	B-Application
distribution	I-Application
built	O
around	O
the	O
GNU	B-Application
Guix	I-Application
package	B-Application
manager	I-Application
.	O
</s>
<s>
It	O
uses	O
the	O
GNU	B-Operating_System
Shepherd	O
init	B-Operating_System
system	O
and	O
the	O
Linux-libre	B-Application
kernel	O
,	O
with	O
support	O
for	O
the	O
GNU	B-Application
Hurd	I-Application
kernel	O
under	O
development	O
.	O
</s>
<s>
On	O
February	O
3	O
,	O
2015	O
,	O
the	B-Operating_System
Free	I-Operating_System
Software	I-Operating_System
Foundation	I-Operating_System
added	O
the	O
distribution	O
to	O
its	O
list	O
of	O
endorsed	O
free	O
Linux	B-Application
distributions	I-Application
.	O
</s>
<s>
The	O
Guix	B-Application
package	B-Application
manager	I-Application
and	O
the	O
Guix	B-Application
System	O
drew	O
inspiration	O
from	O
and	O
were	O
based	O
on	O
the	O
Nix	B-Application
package	I-Application
manager	I-Application
and	O
NixOS	O
respectively	O
.	O
</s>
<s>
The	O
following	O
CPU	O
architectures	O
are	O
supported	O
:	O
IA-32	B-Device
,	O
x86-64	B-Device
,	O
ARM7	O
,	O
AArch64	B-Architecture
,	O
POWER9	B-Device
.	O
</s>
<s>
System	O
services	O
,	O
defined	O
in	O
Guile	B-Application
Scheme	I-Application
,	O
enable	O
the	O
user	O
to	O
declaratively	O
compose	O
the	O
configuration	O
of	O
daemons	O
and	O
background	O
services	O
and	O
specify	O
configurations	O
.	O
</s>
<s>
This	O
enables	O
the	O
user	O
,	O
within	O
a	O
single	O
configuration	O
file	O
or	O
modularized	O
configuration	O
,	O
to	O
configure	O
the	O
whole	O
operating	O
system	O
(	O
e.g.	O
,	O
to	O
have	O
a	O
tor	O
proxy	O
,	O
an	O
sshd	O
server	O
,	O
and	O
a	O
webserver	O
serving	O
guix-web	O
via	O
nginx	O
on	O
a	O
specific	O
port	O
at	O
bootup	O
)	O
.	O
</s>
<s>
The	O
Guix	B-Application
System	O
uses	O
the	O
GNU	B-Operating_System
Daemon	O
Shepherd	O
,	O
formerly	O
known	O
as	O
"	O
dmd	O
"	O
(	O
"	O
Daemon	O
managing	O
Daemons	O
"	O
)	O
,	O
as	O
its	O
init	B-Operating_System
system	O
,	O
which	O
is	O
developed	O
in	O
tandem	O
with	O
Guix	B-Application
and	O
is	O
written	O
and	O
configurable	O
in	O
Guile	B-Application
.	O
</s>
<s>
It	O
supplies	O
user-space	B-Operating_System
functionality	O
asynchronously	O
as	O
services	O
,	O
which	O
under	O
Shepherd	O
are	O
generic	O
functions	O
and	O
object	O
data	O
types	O
which	O
it	O
uses	O
to	O
extend	O
the	O
base	O
operating	O
system	O
in	O
a	O
defined	O
way	O
.	O
</s>
<s>
In	O
contrast	O
to	O
systemd	B-Application
,	O
a	O
userspace	B-Operating_System
shepherd	O
process	O
runs	O
as	O
the	O
user	O
.	O
</s>
<s>
Central	O
to	O
the	O
Shepherd	O
model	O
of	O
user	B-Operating_System
space	I-Operating_System
initialization	O
is	O
the	O
concept	O
of	O
the	O
extension	O
,	O
a	O
form	O
of	O
composability	O
whereby	O
services	O
are	O
designed	O
to	O
be	O
layered	O
onto	O
other	O
services	O
,	O
augmenting	O
them	O
with	O
more	O
elaborate	O
or	O
specialised	O
behaviours	O
as	O
desired	O
.	O
</s>
<s>
This	O
expresses	O
the	O
instantiation-based	O
dependency	O
relationships	O
found	O
in	O
many	O
modern	O
init	B-Operating_System
systems	O
,	O
making	O
the	O
system	O
modular	O
,	O
but	O
also	O
allows	O
services	O
to	O
interact	O
variadically	B-Language
with	O
other	O
services	O
in	O
arbitrary	O
ways	O
,	O
e.g.	O
</s>
<s>
Shepherd	O
also	O
provides	O
virtual	O
services	O
which	O
allow	O
dynamic	O
dispatch	O
over	O
a	O
class	O
of	O
related	O
service	O
objects	O
,	O
such	O
as	O
all	O
those	O
which	O
instantiate	O
a	O
mail	B-Protocol
transfer	I-Protocol
agent	I-Protocol
(	O
MTA	O
)	O
for	O
the	O
system	O
.	O
</s>
<s>
A	O
system	O
governed	O
via	O
the	O
Shepherd	O
daemon	O
can	O
represent	O
its	O
user	B-Operating_System
space	I-Operating_System
as	O
a	O
directed	O
acyclic	O
graph	O
,	O
with	O
the	O
"	O
system-service	O
,	O
"	O
which	O
is	O
responsible	O
for	O
early	O
phases	O
of	O
boot	O
and	O
init	B-Operating_System
,	O
as	O
its	O
root	O
,	O
and	O
all	O
subsequently	O
initialized	O
services	O
as	O
extensions	O
to	O
system-service	O
functionality	O
,	O
either	O
directly	O
or	O
transitively	O
over	O
other	O
services	O
.	O
</s>
<s>
It	O
is	O
intended	O
to	O
be	O
highly	O
programmable	O
by	O
the	O
system	O
administrator	O
using	O
Guile	B-Application
,	O
but	O
it	O
can	O
also	O
be	O
used	O
to	O
manage	O
per-user	O
profiles	O
of	O
unprivileged	O
daemons	O
and	O
services	O
.	O
</s>
<s>
Its	O
services	O
and	O
configuration	O
are	O
stored	O
uniformly	O
as	O
object-oriented	B-Language
Scheme	B-Language
code	O
,	O
and	O
while	O
a	O
core	O
set	O
of	O
services	O
are	O
provided	O
with	O
the	O
basic	O
Guix	B-Application
System	O
,	O
arbitrary	O
new	O
services	O
can	O
be	O
flexibly	O
declared	O
,	O
and	O
through	O
Guile	B-Application
's	O
object	B-Language
system	I-Language
,	O
GOOPS	O
,	O
existing	O
services	O
can	O
be	O
redefined	O
at	O
the	O
user	O
's	O
discretion	O
by	O
asking	O
the	O
Shepherd	O
to	O
dynamically	O
rewrite	O
services	O
in	O
specified	O
ways	O
on	O
instantiation	O
.	O
</s>
<s>
GNU	B-Operating_System
Shepherd	O
was	O
originally	O
designed	O
to	O
work	O
with	O
GNU	B-Application
Hurd	I-Application
,	O
and	O
was	O
later	O
adopted	O
by	O
Guix	B-Application
System	O
.	O
</s>
<s>
To	O
date	O
,	O
the	O
Guix	B-Application
System	O
is	O
dependent	O
on	O
unstable	O
git	O
repository	O
development	O
shared	O
with	O
Guix	B-Application
but	O
enables	O
users	O
or	O
organizations	O
to	O
set	O
up	O
stable	O
release	O
channels	O
themselves	O
via	O
the	O
channel-feature	O
.	O
</s>
<s>
Packages	O
in	O
Guix	B-Application
are	O
generally	O
very	O
up-to-date	O
thanks	O
to	O
the	O
lack	O
of	O
a	O
package	O
maintainer	O
bottlenecks	O
.	O
</s>
<s>
Anyone	O
can	O
contribute	O
an	O
update	O
subject	O
to	O
community	O
approval	O
and	O
the	O
process	O
is	O
assisted	O
by	O
tools	O
such	O
as	O
guix	B-Application
refresh	O
.	O
</s>
<s>
The	O
way	O
Guix	B-Application
pull	O
operates	O
means	O
users	O
retain	O
a	O
working	O
system	O
in	O
the	O
meantime	O
.	O
</s>
<s>
This	O
means	O
that	O
the	O
kind	O
of	O
stable	O
channel	O
that	O
is	O
very	O
common	O
in	O
other	O
Linux	B-Application
distributions	I-Application
is	O
no	O
longer	O
needed	O
for	O
users	O
who	O
are	O
willing	O
to	O
report	O
a	O
bug	O
and	O
wait	O
a	O
few	O
minutes	O
,	O
when	O
trying	O
to	O
update	O
via	O
guix	B-Application
pull	O
.	O
</s>
<s>
Jesse	O
Smith	O
from	O
DistroWatch	O
Weekly	O
reviewed	O
GNU	B-Application
Guix	I-Application
System	I-Application
0.15.0	O
(	O
at	O
the	O
time	O
named	O
GuixSD	B-Application
)	O
,	O
and	O
said	O
,	O
"	O
GuixSD	B-Application
has	O
a	O
package	B-Application
manager	I-Application
that	O
I	O
like	O
"	O
,	O
but	O
criticized	O
the	O
limited	O
hardware	O
support	O
and	O
its	O
limited	O
documentation	O
.	O
</s>
