<s>
A	O
delta	B-Application
update	I-Application
is	O
a	O
software	O
update	O
that	O
only	O
requires	O
the	O
user	O
to	O
download	O
those	O
parts	O
of	O
the	O
software	O
's	O
code	O
which	O
are	O
new	O
,	O
or	O
have	O
been	O
changed	O
from	O
their	O
previous	O
state	O
,	O
in	O
contrast	O
to	O
having	O
to	O
download	O
the	O
entire	O
program	O
.	O
</s>
<s>
The	O
use	O
of	O
delta	B-Application
updates	I-Application
can	O
save	O
significant	O
amounts	O
of	O
time	O
and	O
computing	O
bandwidth	O
.	O
</s>
<s>
By	O
using	O
a	O
delta	B-Application
update	I-Application
,	O
a	O
program	O
can	O
be	O
updated	O
more	O
quickly	O
and	O
efficiently	O
.	O
</s>
<s>
For	O
example	O
:	O
An	O
auto	O
racing	O
simulation	O
game	O
has	O
a	O
size	O
of	O
300	O
megabytes	O
;	O
it	O
is	O
updated	O
to	O
include	O
a	O
new	O
racetrack	O
,	O
and	O
the	O
body	O
of	O
code	O
which	O
inserts	O
the	O
new	O
racetrack	O
into	O
the	O
game	O
has	O
a	O
size	O
of	O
two	O
megabytes	O
;	O
the	O
game	O
may	O
use	O
a	O
delta	B-Application
update	I-Application
,	O
which	O
would	O
require	O
the	O
download	O
of	O
only	O
the	O
two	O
megabytes	O
of	O
new	O
code	O
,	O
instead	O
of	O
a	O
total	O
download	O
of	O
302	O
megabytes	O
.	O
</s>
<s>
Fedora	O
Linux	O
has	O
supported	O
binary	O
delta	B-Application
updates	I-Application
by	O
default	O
using	O
the	O
yum	B-Application
presto	O
plugin	O
since	O
June	O
2009	O
.	O
</s>
<s>
This	O
is	O
based	O
on	O
RPM	B-Application
Package	I-Application
Manager	I-Application
's	O
deltarpm	B-Application
system	O
(	O
2004	O
)	O
,	O
which	O
was	O
in	O
turn	O
based	O
on	O
bsdiff	O
.	O
</s>
<s>
OpenSUSE	O
also	O
uses	O
deltarpms	B-Application
with	O
its	O
zypper	O
manager	O
.	O
</s>
<s>
A	O
similar	O
system	O
for	O
the	O
dpkg-APT	O
package	O
manager	O
system	O
of	O
Debian	O
is	O
debdelta	O
(	O
2006	O
)	O
;	O
despite	O
an	O
apparent	O
halt	O
on	O
the	O
homepage	O
,	O
its	O
package	O
repository	O
as	O
well	O
as	O
the	O
source	O
code	O
remains	O
actively	O
maintained	O
.	O
</s>
<s>
A	O
descendant	O
of	O
Debian	O
,	O
Ubuntu	B-Operating_System
developers	O
have	O
tried	O
many	O
times	O
to	O
implement	O
delta	B-Application
updates	I-Application
for	O
their	O
system	O
.	O
</s>
<s>
The	O
Arch	O
Linux	O
package	O
manager	O
pacman	O
used	O
to	O
support	O
a	O
form	O
of	O
delta	O
updating	O
using	O
VCDIFF	B-Application
(	O
xdelta	O
)	O
.	O
</s>
<s>
Windows	O
Update	O
has	O
supported	O
delta	B-Application
updates	I-Application
since	O
Windows	B-Application
XP	I-Application
which	O
are	O
called	O
express	O
installation	O
files	O
.	O
</s>
<s>
On	O
redistributing	O
updates	O
,	O
Windows	O
Server	O
Update	O
Services	O
has	O
supported	O
delta	B-Application
updates	I-Application
since	O
Windows	O
Server	O
2003	O
.	O
</s>
<s>
FreeBSD	B-Operating_System
has	O
supported	O
delta	B-Application
updates	I-Application
using	O
portsnap	B-Application
since	O
November	O
2005	O
.	O
</s>
<s>
Given	O
FreeBSD	B-Operating_System
's	O
traditional	O
stance	O
of	O
focusing	O
on	O
source	O
code	O
updates	O
,	O
no	O
method	O
of	O
delta	O
binary	O
updates	O
currently	O
exists	O
.	O
</s>
<s>
Google	B-Application
refers	O
to	O
delta	B-Application
updates	I-Application
as	O
"	O
smart	O
updates.	O
"	O
</s>
<s>
This	O
has	O
been	O
implemented	O
in	O
Google	B-Application
's	I-Application
Android	I-Application
operating	O
system	O
devices	O
that	O
run	O
on	O
Android	B-Application
2.3	I-Application
or	O
above	O
.	O
</s>
<s>
Google	B-Application
engineers	O
have	O
estimated	O
that	O
smart	O
updates	O
would	O
be	O
only	O
about	O
one	O
third	O
the	O
size	O
of	O
a	O
full	O
update	O
on	O
average	O
.	O
</s>
<s>
Google	B-Application
's	I-Application
open	O
source	O
project	O
Chromium	B-Language
requires	O
frequent	O
updates	O
to	O
narrow	O
the	O
window	O
of	O
vulnerability	O
.	O
</s>
<s>
It	O
uses	O
a	O
disassembly-based	O
diffing	O
algorithm	O
called	O
"	O
courgette	O
"	O
to	O
reduce	O
diff	B-Application
size	O
of	O
two	O
binary	O
executable	O
files	O
,	O
which	O
reduces	O
the	O
diff	B-Application
patch	O
from	O
6.7	O
%	O
(	O
bsdiff	O
)	O
to	O
0.76	O
%	O
(	O
bsdiff	O
+	O
courgette	O
)	O
for	O
one	O
version	O
update	O
.	O
</s>
<s>
App	O
APK	O
updates	O
in	O
Android	B-Application
's	O
Play	O
Store	O
use	O
bsdiff	O
since	O
2016	O
,	O
a	O
new	O
efficient	O
delta	B-Application
update	I-Application
algorithm	O
introduced	O
in	O
2003	O
.	O
</s>
<s>
Apple	O
's	O
iOS	B-Application
is	O
also	O
capable	O
of	O
delta	B-Application
updates	I-Application
for	O
operating	O
system	O
and	O
application	O
updates	O
to	O
reduce	O
bandwidth	O
usage	O
.	O
</s>
<s>
Over-the-air	O
(	O
OTA	O
)	O
software	O
updates	O
have	O
been	O
used	O
widely	O
across	O
many	O
mobile	O
devices	O
;	O
Apple	O
iOS	B-Application
,	O
Google	B-Application
Android	I-Application
,	O
Microsoft	O
Windows	O
Phone	O
8	O
,	O
and	O
BlackBerry	B-Application
10	I-Application
.	O
</s>
