<s>
The	O
Yellowdog	B-Application
Updater	I-Application
,	I-Application
Modified	I-Application
(	O
YUM	B-Application
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
command-line	B-Application
package-management	B-Application
utility	O
for	O
computers	O
running	O
the	O
Linux	B-Application
operating	I-Application
system	I-Application
using	O
the	O
RPM	B-Application
Package	I-Application
Manager	I-Application
.	O
</s>
<s>
Though	O
YUM	B-Application
has	O
a	O
command-line	B-Application
interface	I-Application
,	O
several	O
other	O
tools	O
provide	O
graphical	B-Application
user	I-Application
interfaces	I-Application
to	O
YUM	B-Application
functionality	O
.	O
</s>
<s>
YUM	B-Application
allows	O
for	O
automatic	O
updates	O
and	O
package	O
and	O
dependency	O
management	O
on	O
RPM-based	B-Application
distributions	O
.	O
</s>
<s>
Like	O
the	O
Advanced	B-Application
Package	I-Application
Tool	I-Application
(	O
APT	B-Application
)	O
from	O
Debian	O
,	O
YUM	B-Application
works	O
with	O
software	B-Application
repositories	I-Application
(	O
collections	O
of	O
packages	O
)	O
,	O
which	O
can	O
be	O
accessed	O
locally	O
or	O
over	O
a	O
network	O
connection	O
.	O
</s>
<s>
Under	O
the	O
hood	O
,	O
YUM	B-Application
depends	O
on	O
RPM	B-Application
,	O
which	O
is	O
a	O
packaging	O
standard	O
for	O
digital	O
distribution	O
of	O
software	O
,	O
which	O
automatically	O
uses	O
hashes	B-Algorithm
and	O
digital	B-Application
signatures	I-Application
to	O
verify	O
the	O
authorship	O
and	O
integrity	O
of	O
said	O
software	O
;	O
unlike	O
some	O
app	B-Application
stores	I-Application
,	O
which	O
serve	O
a	O
similar	O
function	O
,	O
neither	O
YUM	B-Application
nor	O
RPM	B-Application
provide	O
built-in	O
support	O
for	O
proprietary	O
restrictions	O
on	O
copying	O
of	O
packages	O
by	O
end-users	O
.	O
</s>
<s>
YUM	B-Application
is	O
implemented	O
as	O
libraries	O
in	O
the	O
Python	B-Language
programming	I-Language
language	I-Language
,	O
with	O
a	O
small	O
set	O
of	O
programs	O
that	O
provide	O
a	O
command-line	B-Application
interface	I-Application
.	O
</s>
<s>
GUI-based	O
wrappers	O
such	O
as	O
YUM	B-Application
Extender	I-Application
(	O
yumex	B-Application
)	O
also	O
exist	O
,	O
and	O
has	O
been	O
adopted	O
for	O
Fedora	O
Linux	B-Application
until	O
version	O
22	O
.	O
</s>
<s>
A	O
rewrite	O
of	O
YUM	B-Application
named	O
DNF	B-Application
replaced	O
YUM	B-Application
as	O
the	O
default	O
package	B-Application
manager	I-Application
in	O
Fedora	O
22	O
.	O
</s>
<s>
This	O
was	O
required	O
due	O
to	O
Fedora	O
's	O
transition	O
from	O
Python	B-Language
2	O
to	O
Python	B-Language
3	O
,	O
which	O
is	O
n't	O
supported	O
by	O
YUM	B-Application
.	O
</s>
<s>
DNF	B-Application
also	O
improves	O
on	O
YUM	B-Application
in	O
several	O
ways	O
-	O
improved	O
performance	O
,	O
better	O
resolution	O
of	O
dependency	O
conflicts	O
,	O
and	O
easier	O
integration	O
with	O
other	O
software	O
applications	O
.	O
</s>
<s>
The	O
original	O
package	B-Application
manager	I-Application
,	O
Yellowdog	B-Application
UPdater	I-Application
(	O
YUP	O
)	O
was	O
developed	O
in	O
1999-2001	O
by	O
Dan	O
Burcaw	O
,	O
Bryan	O
Stillwell	O
,	O
Stephen	O
Edie	O
,	O
and	O
Troy	O
Bengegerdes	O
at	O
Terra	O
Soft	O
Solutions	O
(	O
under	O
the	O
leadership	O
of	O
then	O
CEO	O
Kai	O
Staats	O
)	O
as	O
a	O
back-end	O
engine	O
for	O
a	O
graphical	O
installer	O
of	O
Yellow	B-General_Concept
Dog	I-General_Concept
Linux	I-General_Concept
.	O
</s>
<s>
As	O
a	O
full	O
rewrite	O
of	O
YUP	O
,	O
YUM	B-Application
evolved	O
primarily	O
to	O
update	O
and	O
manage	O
Red	O
Hat	O
Linux	B-Application
systems	O
used	O
at	O
the	O
Duke	O
University	O
Department	O
of	O
Physics	O
by	O
Seth	B-Application
Vidal	I-Application
and	O
Michael	O
Stenner	O
.	O
</s>
<s>
Vidal	O
continued	O
to	O
contribute	O
to	O
YUM	B-Application
until	O
his	O
death	O
in	O
a	O
Durham	O
,	O
North	O
Carolina	O
bicycle	O
accident	O
on	O
8	O
July	O
2013	O
.	O
</s>
<s>
In	O
2003	O
Robert	O
G	O
.	O
Brown	O
at	O
Duke	O
published	O
documentation	O
for	O
YUM	B-Application
.	O
</s>
<s>
Subsequent	O
adopters	O
included	O
Fedora	O
,	O
Rocky	O
Linux	B-Application
,	O
AlmaLinux	O
,	O
CentOS	O
,	O
and	O
many	O
other	O
RPM-based	B-Application
Linux	I-Application
distributions	I-Application
,	O
including	O
Yellow	B-General_Concept
Dog	I-General_Concept
Linux	I-General_Concept
itself	O
,	O
where	O
YUM	B-Application
replaced	O
the	O
original	O
YUP	O
utility	O
—	O
last	O
updated	O
on	O
SourceForge	B-Application
in	O
2001	O
.	O
</s>
<s>
By	O
2005	O
,	O
it	O
was	O
estimated	O
to	O
be	O
in	O
use	O
on	O
over	O
half	O
of	O
the	O
Linux	B-Application
market	O
,	O
and	O
by	O
2007	O
YUM	B-Application
was	O
considered	O
the	O
"	O
tool	O
of	O
choice	O
"	O
for	O
RPM-based	B-Application
Linux	I-Application
distributions	I-Application
.	O
</s>
<s>
YUM	B-Application
aimed	O
to	O
address	O
both	O
the	O
perceived	O
deficiencies	O
in	O
the	O
old	O
APT-RPM	B-Application
,	O
and	O
restrictions	O
of	O
the	O
Red	O
Hat	O
up2date	B-Application
package	B-Application
management	I-Application
tool	O
.	O
</s>
<s>
YUM	B-Application
superseded	O
up2date	B-Application
in	O
Red	O
Hat	O
Enterprise	O
Linux	B-Application
5	O
and	O
later	O
.	O
</s>
<s>
Some	O
authors	O
refer	O
to	O
YUM	B-Application
as	O
the	O
Yellowdog	O
Update	O
Manager	O
,	O
or	O
suggest	O
that	O
"	O
Your	O
Update	O
Manager	O
"	O
would	O
be	O
more	O
appropriate	O
.	O
</s>
<s>
A	O
basic	O
knowledge	O
of	O
YUM	B-Application
is	O
often	O
included	O
as	O
a	O
requirement	O
for	O
Linux	B-Application
system-administrator	O
certification	O
.	O
</s>
<s>
The	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
of	O
YUM	B-Application
allows	O
the	O
free	B-License
and	I-License
open-source	I-License
software	I-License
to	O
be	O
freely	O
distributed	O
and	O
modified	O
without	O
any	O
royalty	O
,	O
if	O
other	O
terms	O
of	O
the	O
license	O
are	O
honored	O
.	O
</s>
<s>
While	O
yum	B-Application
was	O
originally	O
created	O
for	O
Linux	B-Application
,	O
it	O
has	O
been	O
ported	O
to	O
a	O
number	O
of	O
other	O
operating	B-General_Concept
systems	I-General_Concept
including	O
AIX	B-Application
,	O
IBM	B-Application
i	I-Application
,	O
and	O
ArcaOS	B-Device
.	O
</s>
<s>
YUM	B-Application
can	O
perform	O
operations	O
such	O
as	O
:	O
</s>
<s>
The	O
2.x	O
versions	O
of	O
YUM	B-Application
feature	O
an	O
additional	O
interface	O
for	O
programming	O
extensions	O
in	O
Python	B-Language
that	O
allows	O
the	O
behavior	O
of	O
YUM	B-Application
to	O
be	O
altered	O
.	O
</s>
<s>
A	O
commonly	O
installed	O
package	O
yum-utils	O
,	O
contains	O
commands	O
which	O
use	O
the	O
YUM	B-Application
API	O
,	O
and	O
many	O
plugins	O
.	O
</s>
<s>
Graphical	B-Application
user	I-Application
interfaces	I-Application
,	O
known	O
as	O
"	O
front-ends	O
"	O
,	O
allow	O
easier	O
use	O
of	O
YUM	B-Application
.	O
</s>
<s>
PackageKit	B-Language
and	O
Yum	B-Application
Extender	I-Application
(	O
yumex	B-Application
)	O
are	O
two	O
examples	O
.	O
</s>
<s>
Yum	B-Application
Extender	I-Application
was	O
deprecated	O
for	O
a	O
while	O
when	O
Fedora	O
migrated	O
to	O
DNF	B-Application
,	O
but	O
it	O
was	O
rewritten	O
in	O
Python	B-Language
3	O
and	O
Gtk	O
3	O
and	O
has	O
been	O
in	O
progress	O
for	O
development	O
.	O
</s>
<s>
This	O
brand-new	O
Yum	B-Application
Extender	I-Application
is	O
available	O
for	O
Fedora	O
34	O
or	O
newer	O
.	O
</s>
<s>
The	O
hope	O
is	O
to	O
avoid	O
a	O
situation	O
known	O
as	O
dependency	B-Protocol
hell	I-Protocol
.	O
</s>
<s>
A	O
separate	O
tool	O
,	O
createrepo	O
,	O
sets	O
up	O
YUM	B-Application
software	B-Application
repositories	I-Application
,	O
generating	O
the	O
necessary	O
metadata	O
in	O
a	O
standard	O
XML	B-Protocol
format	O
(	O
and	O
the	O
SQLite	B-Language
metadata	O
if	O
given	O
the	O
-d	O
option	O
)	O
.	O
</s>
<s>
YUM	B-Application
's	O
XML	B-Protocol
repository	O
,	O
built	O
with	O
input	O
from	O
many	O
other	O
developers	O
,	O
quickly	O
became	O
the	O
standard	O
for	O
RPM-based	B-Application
repositories	O
.	O
</s>
<s>
Besides	O
the	O
distributions	O
that	O
use	O
YUM	B-Application
directly	O
,	O
SUSE	O
Linux	B-Application
10.1	O
added	O
support	O
for	O
YUM	B-Application
repositories	O
in	O
YaST	B-Device
,	O
and	O
the	O
Open	B-Application
Build	I-Application
Service	I-Application
repositories	O
use	O
the	O
YUM	B-Application
XML	B-Protocol
repository	O
format	O
metadata	O
.	O
</s>
<s>
YUM	B-Application
automatically	O
synchronizes	O
the	O
remote	O
meta	O
data	O
to	O
the	O
local	O
client	O
,	O
with	O
other	O
tools	O
opting	O
to	O
synchronize	O
only	O
when	O
requested	O
by	O
the	O
user	O
.	O
</s>
<s>
Having	O
automatic	O
synchronization	O
means	O
that	O
YUM	B-Application
cannot	O
fail	O
due	O
to	O
the	O
user	O
failing	O
to	O
run	O
a	O
command	O
at	O
the	O
correct	O
interval	O
.	O
</s>
