<s>
GNU	B-Application
Guix	I-Application
(	O
)	O
is	O
a	O
functional	B-Language
cross-platform	O
package	B-Application
manager	I-Application
and	O
a	O
tool	O
to	O
instantiate	O
and	O
manage	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
based	O
on	O
the	O
Nix	B-Application
package	I-Application
manager	I-Application
.	O
</s>
<s>
Configuration	O
and	O
package	O
recipes	O
are	O
written	O
in	O
Guile	B-Application
Scheme	I-Application
.	O
</s>
<s>
GNU	B-Application
Guix	I-Application
is	O
the	O
default	O
package	B-Application
manager	I-Application
of	O
the	O
GNU	B-Application
Guix	I-Application
System	I-Application
distribution	B-Application
.	O
</s>
<s>
Differing	O
from	O
traditional	O
package	B-Application
managers	I-Application
,	O
Guix	B-Application
(	O
like	O
Nix	B-Application
)	O
utilizes	O
a	O
purely	O
functional	B-Language
deployment	O
model	O
where	O
software	O
is	O
installed	O
into	O
unique	O
directories	O
generated	O
through	O
cryptographic	B-Algorithm
hashes	I-Algorithm
.	O
</s>
<s>
All	O
dependencies	O
for	O
each	O
software	O
are	O
included	O
within	O
each	O
hash	B-Algorithm
.	O
</s>
<s>
This	O
solves	O
the	O
problem	O
of	O
dependency	B-Protocol
hell	I-Protocol
,	O
allows	O
multiple	O
versions	O
of	O
the	O
same	O
software	O
to	O
coexist	O
and	O
makes	O
packages	O
portable	O
and	O
reproducible	B-Application
.	O
</s>
<s>
Performing	O
scientific	O
computations	O
in	O
a	O
Guix	B-Application
setup	O
has	O
been	O
proposed	O
as	O
a	O
promising	O
response	O
to	O
the	O
replication	O
crisis	O
.	O
</s>
<s>
The	O
development	O
of	O
GNU	B-Application
Guix	I-Application
is	O
intertwined	O
with	O
the	O
GNU	B-Application
Guix	I-Application
System	I-Application
,	O
an	O
installable	O
operating	O
system	O
distribution	B-Application
using	O
the	O
Linux-libre	B-Application
kernel	O
and	O
GNU	O
Shepherd	O
init	O
system	O
.	O
</s>
<s>
Guix	B-Application
packages	O
are	O
defined	O
through	O
functional	B-Language
Guile	B-Application
Scheme	I-Application
APIs	B-Application
specifically	O
designed	O
for	O
package	B-Application
management	I-Application
.	O
</s>
<s>
Dependencies	O
are	O
tracked	O
directly	O
in	O
this	O
language	O
through	O
special	O
values	O
called	O
"	O
derivations	O
"	O
which	O
are	O
evaluated	O
by	O
the	O
Guix	B-Application
daemon	O
lazily	O
.	O
</s>
<s>
Guix	B-Application
keeps	O
track	O
of	O
these	O
references	O
automatically	O
so	O
that	O
installed	O
packages	O
can	O
be	O
garbage	B-General_Concept
collected	I-General_Concept
when	O
no	O
other	O
package	O
depends	O
on	O
them	O
.	O
</s>
<s>
At	O
the	O
cost	O
of	O
greater	O
storage	O
requirements	O
,	O
all	O
upgrades	O
in	O
Guix	B-Application
are	O
guaranteed	O
to	O
be	O
both	O
atomic	B-General_Concept
and	O
can	O
be	O
rolled	O
back	O
.	O
</s>
<s>
The	O
roll-back	O
feature	O
of	O
Guix	B-Application
is	O
inherited	O
from	O
the	O
design	O
of	O
Nix	B-Application
and	O
is	O
not	O
found	O
in	O
any	O
of	O
the	O
native	O
package	B-Application
managers	I-Application
of	O
popular	O
Linux	O
distributions	O
such	O
as	O
Debian	O
and	O
its	O
derivatives	O
,	O
Arch	O
Linux	O
and	O
its	O
derivatives	O
,	O
or	O
in	O
other	O
major	O
distributions	O
such	O
as	O
Fedora	O
,	O
CentOS	O
or	O
openSUSE	O
.	O
</s>
<s>
The	O
Guix	B-Application
package	B-Application
manager	I-Application
can	O
however	O
be	O
used	O
in	O
such	O
distributions	O
and	O
is	O
available	O
for	O
Debian	O
and	O
Parabola	O
.	O
</s>
<s>
Compared	O
to	O
traditional	O
package	B-Application
managers	I-Application
,	O
Guix	B-Application
package	O
stores	O
can	O
grow	O
considerably	O
bigger	O
and	O
therefore	O
require	O
more	O
bandwidth	O
;	O
although	O
compared	O
to	O
container	B-Application
solutions	O
(	O
like	O
Docker	O
)	O
that	O
are	O
also	O
commonly	O
employed	O
to	O
solve	O
dependency	B-Protocol
hell	I-Protocol
,	O
Guix	B-Application
is	O
leaner	O
and	O
conforms	O
to	O
practices	O
like	O
Do	O
n't	O
repeat	O
yourself	O
and	O
Single	B-Application
source	I-Application
of	I-Application
truth	I-Application
.	O
</s>
<s>
Inherited	O
from	O
the	O
design	O
of	O
Nix	B-Application
,	O
most	O
of	O
the	O
content	O
of	O
the	O
package	B-Application
manager	I-Application
is	O
kept	O
in	O
a	O
directory	O
/gnu/store	O
where	O
only	O
the	O
Guix	B-Application
daemon	O
has	O
write-access	O
.	O
</s>
<s>
This	O
is	O
achieved	O
via	O
specialised	O
bind	O
mounts	O
,	O
where	O
the	O
Store	O
as	O
a	O
file	O
system	O
is	O
mounted	O
read	O
only	O
,	O
prohibiting	O
interference	O
even	O
from	O
the	O
root	O
user	O
,	O
while	O
the	O
Guix	B-Application
daemon	O
remounts	O
the	O
Store	O
as	O
read/writable	O
in	O
its	O
own	O
private	O
namespace	O
.	O
</s>
<s>
Guix	B-Application
talks	O
with	O
this	O
daemon	O
to	O
build	O
things	O
or	O
fetch	O
substitutes	O
which	O
are	O
all	O
kept	O
in	O
the	O
store	O
.	O
</s>
<s>
Guix	B-Application
-	O
like	O
Nix	B-Application
-	O
has	O
built-in	O
garbage	B-General_Concept
collection	I-General_Concept
facilities	O
to	O
help	O
prune	O
dead	O
store	O
items	O
and	O
keep	O
the	O
live	O
ones	O
.	O
</s>
<s>
It	O
is	O
written	O
using	O
Guile	B-Application
.	O
</s>
<s>
guix	B-Application
edit	O
hello	O
)	O
and	O
changed	O
in	O
Guix	B-Application
,	O
making	O
the	O
system	O
transparent	O
and	O
very	O
easily	O
hackable	O
.	O
</s>
<s>
Inherited	O
from	O
the	O
design	O
of	O
Nix	B-Application
,	O
all	O
manipulation	O
of	O
store	O
items	O
is	O
independent	O
of	O
each	O
other	O
,	O
and	O
the	O
directories	O
of	O
the	O
store	O
begin	O
with	O
a	O
base32-encoded	O
hash	B-Algorithm
of	O
the	O
source	O
code	O
of	O
the	O
derivation	O
along	O
with	O
its	O
inputs	O
.	O
</s>
<s>
Guix	B-Application
package	O
uses	O
profiles	O
generations	O
,	O
which	O
are	O
a	O
collection	O
of	O
symlinks	O
to	O
specific	O
store	O
items	O
together	O
comprising	O
what	O
the	O
user	O
has	O
installed	O
into	O
the	O
profile	O
.	O
</s>
<s>
the	O
profile	O
of	O
a	O
user	O
who	O
only	O
installed	O
GNU	O
Hello	O
contains	O
links	O
to	O
the	O
store	O
item	O
which	O
holds	O
the	O
version	O
of	O
hello	O
installed	O
with	O
the	O
currently	O
used	O
guix	B-Application
.	O
</s>
<s>
on	O
version	O
c087a90e06d7b9451f802323e24deb1862a21e0f	O
of	O
guix	B-Application
,	O
this	O
corresponds	O
to	O
the	O
following	O
item	O
:	O
/gnu/store/md2plii4g5sk66wg9cgwc964l3xwhrm9	O
-hello-2.10	O
(	O
built	O
from	O
the	O
recipe	O
above	O
)	O
.	O
</s>
<s>
In	O
addition	O
to	O
symlinks	O
,	O
each	O
profile	O
guix	B-Application
builds	O
also	O
contains	O
a	O
union	O
of	O
all	O
the	O
info-manuals	O
,	O
man-pages	O
,	O
icons	O
,	O
fonts	O
,	O
etc	O
.	O
</s>
<s>
The	O
default	O
symlinks	O
to	O
profile	O
generations	O
are	O
stored	O
under	O
/var/guix	O
in	O
the	O
filesystem	O
.	O
</s>
<s>
The	O
user	O
can	O
create	O
any	O
number	O
of	O
profiles	O
by	O
invoking	O
guix	B-Application
package	O
-p	O
PROFILE-NAME	O
COMMAND	O
.	O
</s>
<s>
Guix	B-Application
package	O
enables	O
instantaneous	O
roll-back	O
to	O
a	O
previous	O
profile	O
generation	O
via	O
changing	O
the	O
symlink	O
to	O
an	O
earlier	O
profile	O
generation	O
.	O
</s>
<s>
this	O
item	O
is	O
a	O
profile	O
containing	O
hello	O
above	O
:	O
/gnu/store/b4wipjlsapvnijmbawl7sh76087vpl4n	O
-profile	O
(	O
built	O
and	O
activated	O
when	O
running	O
guix	B-Application
install	O
hello	O
)	O
.	O
</s>
<s>
Guix	B-Application
environment	O
enables	O
the	O
user	O
to	O
easily	O
enter	O
an	O
environment	O
where	O
all	O
the	O
necessary	O
packages	O
for	O
development	O
of	O
software	O
are	O
present	O
without	O
clogging	O
up	O
the	O
users	O
default	O
profile	O
with	O
dependencies	O
for	O
multiple	O
projects	O
.	O
</s>
<s>
running	O
guix	B-Application
environment	O
hello	O
enters	O
a	O
throw-away	O
environment	O
where	O
everything	O
needed	O
to	O
compile	O
hello	O
on	O
guix	B-Application
is	O
present	O
(	O
gcc	O
,	O
guile	B-Application
,	O
etc	O
.	O
</s>
<s>
If	O
you	O
want	O
a	O
persistent	O
gc-rooted	O
environment	O
that	O
is	O
not	O
garbage	B-General_Concept
collected	I-General_Concept
on	O
the	O
next	O
run	O
of	O
guix	B-Application
gc	O
you	O
can	O
create	O
a	O
root	O
:	O
</s>
<s>
running	O
guix	B-Application
environment	O
--root	O
=	O
hello-root	O
hello	O
enters	O
an	O
environment	O
where	O
everything	O
needed	O
to	O
compile	O
guix	B-Application
is	O
present	O
(	O
gcc	O
,	O
guile	B-Application
,	O
etc	O
.	O
)	O
</s>
<s>
Guix	B-Application
pack	O
enables	O
the	O
user	O
to	O
bundle	O
together	O
store	O
items	O
and	O
output	O
them	O
as	O
a	O
docker	O
binary	O
image	O
,	O
a	O
relocatable	O
tarball	O
or	O
a	O
squashfs	O
binary	O
.	O
</s>
<s>
Guix	B-Application
graph	O
enables	O
the	O
user	O
to	O
view	O
different	O
graphs	O
of	O
the	O
packages	O
and	O
their	O
dependencies	O
.	O
</s>
<s>
GNU	B-Application
Guix	I-Application
System	I-Application
uses	O
Guix	B-Application
as	O
its	O
package	B-Application
manager	I-Application
and	O
configuration	O
system	O
,	O
similar	O
to	O
how	O
NixOS	O
uses	O
Nix	B-Application
.	O
</s>
<s>
The	B-Application
GNU	I-Application
Project	I-Application
announced	O
in	O
November	O
2012	O
the	O
first	O
release	O
of	O
GNU	B-Application
Guix	I-Application
,	O
a	O
functional	B-Language
package	B-Application
manager	I-Application
based	O
on	O
Nix	B-Application
that	O
provides	O
,	O
among	O
other	O
things	O
,	O
Guile	B-Application
Scheme	I-Application
APIs	B-Application
.	O
</s>
<s>
The	O
project	O
was	O
started	O
in	O
June	O
2012	O
by	O
Ludovic	O
Courtès	O
,	O
one	O
of	O
the	O
GNU	B-Application
Guile	I-Application
hackers	O
.	O
</s>
<s>
On	O
August	O
20	O
,	O
2015	O
,	O
it	O
was	O
announced	O
that	O
Guix	B-Application
had	O
been	O
ported	O
to	O
GNU	B-Application
Hurd	I-Application
.	O
</s>
