<s>
Metalink	B-Application
is	O
an	O
extensible	O
metadata	O
file	O
format	O
that	O
describes	O
one	O
or	O
more	O
computer	B-Operating_System
files	I-Operating_System
available	O
for	O
download	B-Application
.	O
</s>
<s>
It	O
specifies	O
files	O
appropriate	O
for	O
the	O
user	O
's	O
language	O
and	O
operating	B-General_Concept
system	I-General_Concept
;	O
facilitates	O
file	B-Error_Name
verification	I-Error_Name
and	O
recovery	O
from	O
data	O
corruption	O
;	O
and	O
lists	O
alternate	O
download	B-Application
sources	O
(	O
mirror	O
URIs	B-Protocol
)	O
.	O
</s>
<s>
The	O
metadata	O
is	O
encoded	O
in	O
HTTP	B-Protocol
header	I-Protocol
fields	I-Protocol
and/or	O
in	O
an	O
XML	B-Protocol
file	O
with	O
extension	O
or	O
.	O
</s>
<s>
The	O
duplicate	O
download	B-Application
locations	O
provide	O
reliability	O
in	O
case	O
one	O
method	O
fails	O
.	O
</s>
<s>
Some	O
clients	O
also	O
achieve	O
faster	O
download	B-Application
speeds	O
by	O
allowing	O
different	O
chunks/segments	O
of	O
each	O
file	O
to	O
be	O
downloaded	B-Application
from	O
multiple	O
resources	O
at	O
the	O
same	O
time	O
(	O
segmented	O
downloading	B-Application
)	O
.	O
</s>
<s>
Metalink	B-Application
supports	O
listing	O
multiple	O
partial	O
and	O
full	O
file	O
hashes	B-Algorithm
along	O
with	O
PGP	B-Application
signatures	O
.	O
</s>
<s>
Most	O
clients	O
only	O
support	O
verifying	O
MD5	B-Algorithm
,	O
SHA-1	B-Algorithm
,	O
and	O
SHA-256	B-Algorithm
,	O
however	O
.	O
</s>
<s>
Besides	O
FTP	O
and	O
HTTP	B-Protocol
mirror	O
locations	O
and	O
rsync	B-Application
,	O
it	O
also	O
supports	O
listing	O
the	O
P2P	O
methods	O
BitTorrent	B-Protocol
,	O
ed2k	B-Protocol
,	O
magnet	B-Protocol
link	I-Protocol
or	O
any	O
other	O
that	O
uses	O
a	O
URI	B-Protocol
.	O
</s>
<s>
Metalink	B-Application
3.0	O
was	O
publicly	O
released	O
in	O
2005	O
.	O
</s>
<s>
It	O
was	O
designed	O
to	O
aid	O
in	O
downloading	B-Application
Linux	B-Application
ISO	B-General_Concept
images	I-General_Concept
and	O
other	O
large	O
files	O
on	O
release	O
day	O
,	O
when	O
servers	O
would	O
be	O
overloaded	O
(	O
each	O
server	O
would	O
have	O
to	O
be	O
tried	O
manually	O
)	O
and	O
to	O
repair	O
large	O
downloads	B-Application
by	O
replacing	O
only	O
the	O
parts	O
with	O
errors	O
instead	O
of	O
fully	O
re-downloading	O
them	O
.	O
</s>
<s>
It	O
was	O
initially	O
adopted	O
by	O
download	B-Protocol
managers	I-Protocol
,	O
and	O
was	O
used	O
by	O
open	B-License
source	I-License
projects	O
such	O
as	O
OpenOffice.org	B-Application
and	O
Linux	B-Application
distributions	I-Application
.	O
</s>
<s>
A	O
community	O
developed	O
around	O
it	O
,	O
more	O
download	B-Application
programs	O
supported	O
it	O
(	O
including	O
proprietary	O
ones	O
)	O
and	O
it	O
saw	O
commercial	O
adoption	O
.	O
</s>
<s>
In	O
2008	O
,	O
the	O
community	O
took	O
their	O
work	O
to	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
which	O
resulted	O
in	O
Metalink	B-Application
4.0	O
in	O
2010	O
,	O
described	O
in	O
a	O
Standards	O
Track	O
RFC	O
.	O
</s>
<s>
Metalink	B-Application
3.0	O
(	O
with	O
the	O
extension	O
)	O
and	O
Metalink	B-Application
4.0	O
(	O
with	O
the	O
extension	O
)	O
are	O
incompatible	O
because	O
they	O
have	O
a	O
slightly	O
different	O
format	O
.	O
</s>
<s>
In	O
2011	O
,	O
another	O
Standards	O
Track	O
RFC	O
described	O
Metalink	B-Application
in	O
HTTP	B-Protocol
header	I-Protocol
fields	I-Protocol
.	O
</s>
<s>
libmetalink	O
(	O
MIT	B-License
License	I-License
)	O
is	O
a	O
Metalink	B-Application
library	O
written	O
in	O
C	B-Language
.	O
It	O
provides	O
the	O
parsing	O
of	O
Metalink	B-Application
XML	B-Protocol
files	O
to	O
programs	O
written	O
in	O
C	B-Language
and	O
uses	O
Expat	B-Language
(	O
library	O
)	O
or	O
libxml2	B-Application
.	O
</s>
<s>
It	O
does	O
not	O
handle	O
the	O
actual	O
downloading	B-Application
of	O
files	O
.	O
</s>
<s>
It	O
is	O
used	O
by	O
cURL	B-Language
and	O
other	O
client	O
programs	O
.	O
</s>
<s>
metalink-checker	O
(	O
GPL	B-License
)	O
is	O
a	O
command	O
line	O
downloader	B-Application
written	O
in	O
Python	B-Language
that	O
supports	O
multi-source	O
downloads	B-Application
and	O
chunk	O
checksums	O
,	O
as	O
well	O
as	O
checking	O
mirrors	O
.	O
</s>
<s>
It	O
can	O
also	O
be	O
used	O
as	O
a	O
Python	B-Language
library	O
.	O
</s>
<s>
Mandriva	O
Linux	B-Application
has	O
integrated	O
Metalink	B-Application
into	O
package	O
management	O
with	O
urpmi	B-Application
and	O
aria2	O
.	O
</s>
<s>
Fedora	O
has	O
integrated	O
Metalink	B-Application
into	O
package	O
management	O
with	O
yum	B-Application
.	O
</s>
<s>
openSUSE	B-Operating_System
has	O
integrated	O
Metalink	B-Application
into	O
package	O
management	O
with	O
ZYpp	O
and	O
aria2	O
.	O
</s>
<s>
Wubi	B-Language
,	O
the	O
Windows-based	B-Language
Ubuntu	I-Language
installer	I-Language
,	O
uses	O
(	O
LGPL	B-Application
)	O
to	O
download	B-Application
Ubuntu	B-Operating_System
ISO	B-General_Concept
images	I-General_Concept
and	O
takes	O
advantage	O
of	O
Metalink	B-Application
's	O
features	O
of	O
higher	O
availability	O
and	O
increased	O
reliability	O
.	O
</s>
<s>
If	O
there	O
are	O
errors	O
in	O
the	O
download	B-Application
,	O
they	O
are	O
repaired	O
,	O
instead	O
of	O
restarting	O
the	O
large	O
download	B-Application
.	O
</s>
<s>
Appupdater	O
(	O
GPL	B-License
)	O
for	O
Windows	B-Application
"	O
is	O
similar	O
to	O
apt-get	O
or	O
yum	B-Application
on	O
Linux	B-Application
.	O
</s>
<s>
Currently	O
,	O
OpenOffice.org	B-Application
uses	O
Metalinks	B-Application
to	O
distribute	O
their	O
free	O
office	O
suite	O
.	O
</s>
<s>
cURL	B-Language
offers	O
Metalinks	B-Application
of	O
their	O
downloads	B-Application
.	O
</s>
<s>
UniProt	O
Consortium	O
also	O
provides	O
a	O
Metalink	B-Application
for	O
their	O
large	O
protein	O
database	O
.	O
</s>
<s>
Dofus	B-Protocol
,	O
a	O
Flash	O
MMORPG	B-Protocol
uses	O
Metalinks	B-Application
for	O
downloads	B-Application
and	O
so	O
does	O
SageMath	B-Application
,	O
the	O
open-source	B-License
mathematical	O
software	O
.	O
</s>
<s>
The	O
software	O
hosting	O
and	O
collaboration	O
platform	O
Origo	O
generates	O
Metalinks	B-Application
for	O
all	O
hosted	O
releases	O
.	O
</s>
<s>
The	O
following	O
Linux	B-Application
distributions	I-Application
use	O
Metalink	B-Application
for	O
ISO	B-General_Concept
image	I-General_Concept
distribution	O
:	O
Adios	O
,	O
Bayanihan	O
Linux	B-Application
,	O
BeleniX	B-Operating_System
,	O
Berry	O
Linux	B-Application
,	O
BLAG	O
Linux	B-Application
and	O
GNU	O
,	O
Bluewhite64	O
Linux	B-Application
,	O
Damn	B-Operating_System
Small	I-Operating_System
Linux	I-Operating_System
,	O
Fedora	O
,	O
GoboLinux	O
,	O
Granular	O
Linux	B-Application
,	O
KateOS	O
,	O
Linux	B-Application
Mint	I-Application
,	O
openSUSE	B-Operating_System
,	O
Pardus	B-Operating_System
Linux	I-Operating_System
,	O
PCLinuxOS	O
,	O
PuppyLinux	O
,	O
Sabayon	O
Linux	B-Application
,	O
StartCom	O
Enterprise	O
Linux	B-Application
,	O
SUSE	O
Linux	B-Application
,	O
Ubuntu	B-Operating_System
.	O
</s>
<s>
The	O
following	O
FreeBSD	B-Operating_System
based	O
distributions	O
use	O
Metalink	B-Application
for	O
ISO	B-General_Concept
image	I-General_Concept
distribution	O
:	O
DesktopBSD	B-Application
,	O
MidnightBSD	B-Application
,	O
and	O
TrueOS	B-Application
.	O
</s>
<s>
A	O
guide	O
to	O
which	O
clients	O
support	O
which	O
Metalink	B-Application
features	O
:	O
</s>
<s>
Multiple	O
Editions/	O
$39.99	O
Professional	O
InterfaceCLI	O
CLI	O
GUI	O
GUI	O
GUI	O
GUI	O
GUI	O
GUI	O
Metalink	B-Application
4.0	O
Runs	O
on	O
Linux	B-Application
Runs	O
on	O
Windows	B-Application
Runs	O
on	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
Resume	O
Downloads	B-Application
?	O
</s>
<s>
Segmented	O
Downloads	B-Application
?	O
</s>
<s>
HTTP	B-Protocol
with	O
Transparent	O
Negotiation	O
?	O
</s>
<s>
Metalink/HTTP	O
?	O
</s>
<s>
HTTP	B-Protocol
FTP	O
BitTorrent	B-Protocol
?	O
</s>
<s>
MD5	B-Algorithm
Hashes	I-Algorithm
?	O
</s>
<s>
SHA-1	B-Algorithm
Hashes	I-Algorithm
?	O
</s>
<s>
SHA-256	B-Algorithm
Hashes	B-Algorithm
?	O
</s>
<s>
Piece	O
Hashes	B-Algorithm
?	O
</s>
<s>
PGP	B-Application
Signatures	O
?	O
</s>
<s>
No	O
clients	O
support	O
rsync	B-Application
at	O
this	O
time	O
.	O
</s>
<s>
Metalink	B-Application
is	O
formatted	O
as	O
XML	B-Protocol
so	O
it	O
can	O
be	O
either	O
hand-crafted	O
or	O
created	O
with	O
an	O
XML	B-Protocol
library	O
,	O
useful	O
for	O
automation	O
.	O
</s>
<s>
These	O
tools	O
are	O
specifically	O
for	O
Metalink	B-Application
.	O
</s>
<s>
Bouncer	O
supports	O
Metalink	B-Application
via	O
a	O
patch	O
that	O
has	O
not	O
yet	O
been	O
integrated	O
upstream	O
.	O
</s>
<s>
Geo	O
McFly	O
(	O
GPL	B-License
)	O
is	O
an	O
on	O
the	O
fly	O
generator	O
of	O
metalinks	B-Application
based	O
on	O
the	O
downloader	B-Application
's	O
geographical	O
location	O
,	O
written	O
in	O
Python	B-Language
.	O
</s>
<s>
Metalink	B-Application
Editor	O
(	O
GPL	B-License
)	O
is	O
a	O
Cross	O
Platform	O
GUI	O
Metalink	B-Application
editor	O
written	O
in	O
Python	B-Language
which	O
allows	O
you	O
to	O
create	O
and	O
edit	O
Metalinks	B-Application
.	O
</s>
<s>
Metalink	B-Application
Library	O
(	O
GPL	B-License
)	O
is	O
a	O
Cross	O
Platform	O
Metalink	B-Application
library	O
for	O
Python	B-Language
and	O
PHP	O
based	O
on	O
Metalink	B-Application
Editor	O
with	O
many	O
automatic	O
features	O
and	O
an	O
easy	O
command-line	O
interface	O
to	O
generate	O
Metalink	B-Application
and	O
Torrent	B-Protocol
files	O
.	O
</s>
<s>
Metalink	B-Application
Generator	O
can	O
also	O
be	O
used	O
to	O
create	O
Metalinks	B-Application
by	O
filling	O
out	O
a	O
Web	O
form	O
.	O
</s>
<s>
Metalink	B-Application
tools	O
(	O
GPL	B-License
)	O
Unix/Windows	O
command	O
line	O
tools	O
for	O
generating	O
Metalinks	B-Application
with	O
hashes	B-Algorithm
and	O
mirror/p2p	O
lists	O
.	O
</s>
<s>
Dynamic	O
online	O
metalinks	B-Application
based	O
on	O
metadata	O
.	O
</s>
<s>
Automatically	O
created	O
metalinks	B-Application
based	O
on	O
metadata	O
published	O
by	O
each	O
mirror	O
.	O
</s>
<s>
MirrorManager	O
(	O
MIT	B-License
X11	I-License
license	I-License
)	O
is	O
used	O
by	O
the	O
Fedora	O
Project	O
for	O
dynamically	O
listing	O
mirrors	O
.	O
</s>
<s>
MirrorBrain	O
(	O
GPL	B-License
,	O
Apache	B-Application
License	I-Application
)	O
is	O
a	O
real-time	O
Metalink	B-Application
generator	O
and	O
download	B-Application
redirector	O
.	O
</s>
<s>
It	O
can	O
either	O
return	O
Metalinks	B-Application
,	O
or	O
automatically	O
redirect	O
non-Metalink	O
clients	O
(	O
per	O
HTTP	B-Protocol
redirection	O
)	O
to	O
a	O
mirror	O
server	O
near	O
them	O
.	O
</s>
<s>
Transparent	O
negotiation	O
of	O
Metalinks	B-Application
,	O
embedding	O
PGP	B-Application
signatures	O
,	O
Metalink/HTTP	O
and	O
other	O
advanced	O
features	O
are	O
supported	O
.	O
</s>
<s>
It	O
is	O
used	O
for	O
instance	O
by	O
openSUSE	B-Operating_System
and	O
OpenOffice.org	B-Application
.	O
</s>
<s>
Metalink	B-Application
4.0	O
files	O
have	O
the	O
extension	O
and	O
are	O
XML	B-Protocol
text	O
files	O
.	O
</s>
<s>
They	O
are	O
served	O
with	O
the	O
application/metalink4	O
+xml	O
Internet	B-Application
media	I-Application
type	I-Application
.	O
</s>
<s>
Metalink	B-Application
in	O
HTTP	B-Protocol
header	I-Protocol
fields	I-Protocol
makes	O
use	O
of	O
existing	O
standard	O
HTTP	B-Protocol
header	I-Protocol
fields	I-Protocol
such	O
as	O
ETags	B-Protocol
,	O
Link	O
header	O
fields	O
(	O
for	O
mirrors	O
and	O
P2P	O
)	O
,	O
and	O
Instance	O
Digests	O
(	O
for	O
hashes	B-Algorithm
)	O
.	O
</s>
<s>
Metalink	B-Application
3.0	O
files	O
have	O
the	O
extension	O
and	O
are	O
XML	B-Protocol
text	O
files	O
.	O
</s>
