<s>
File	B-Application
synchronization	I-Application
(	O
or	O
syncing	B-General_Concept
)	O
in	O
computing	O
is	O
the	O
process	O
of	O
ensuring	O
that	O
computer	B-Operating_System
files	I-Operating_System
in	O
two	O
or	O
more	O
locations	O
are	O
updated	O
via	O
certain	O
rules	O
.	O
</s>
<s>
In	O
one-way	O
file	B-Application
synchronization	I-Application
,	O
also	O
called	O
mirroring	O
,	O
updated	O
files	O
are	O
copied	O
from	O
a	O
source	O
location	O
to	O
one	O
or	O
more	O
target	O
locations	O
,	O
but	O
no	O
files	O
are	O
copied	O
back	O
to	O
the	O
source	O
location	O
.	O
</s>
<s>
In	O
two-way	O
file	B-Application
synchronization	I-Application
,	O
updated	O
files	O
are	O
copied	O
in	O
both	O
directions	O
,	O
usually	O
with	O
the	O
purpose	O
of	O
keeping	O
the	O
two	O
locations	O
identical	O
to	O
each	O
other	O
.	O
</s>
<s>
In	O
this	O
article	O
,	O
the	O
term	O
synchronization	O
refers	O
exclusively	O
to	O
two-way	O
file	B-Application
synchronization	I-Application
.	O
</s>
<s>
File	B-Application
synchronization	I-Application
is	O
commonly	O
used	O
for	O
home	O
backups	B-Application
on	O
external	O
hard	O
drives	O
or	O
updating	O
for	O
transport	O
on	O
USB	O
flash	O
drives	O
.	O
</s>
<s>
BitTorrent	O
Sync	O
,	O
Dropbox	B-Application
and	O
SKYSITE	B-Application
are	O
prominent	O
products	O
.	O
</s>
<s>
Some	O
backup	B-Application
software	I-Application
also	O
support	O
real-time	O
file	B-Application
sync	I-Application
.	O
</s>
<s>
the	O
"	O
snapshot	O
"	O
feature	O
in	O
Beyond	B-Language
Compare	I-Language
or	O
the	O
"	O
package	O
"	O
feature	O
in	O
Synchronize	B-General_Concept
It	I-General_Concept
!	I-General_Concept
)	O
.	O
</s>
<s>
The	O
Unison	B-Application
Manual	O
describes	O
how	O
to	O
do	O
this	O
:	O
</s>
<s>
The	O
big	O
advantage	O
of	O
the	O
star	O
topology	O
is	O
that	O
it	O
eliminates	O
the	O
possibility	O
of	O
confusing	O
"	O
spurious	O
conflicts	O
"	O
arising	O
from	O
the	O
fact	O
that	O
a	O
separate	O
archive	O
is	O
maintained	O
by	O
Unison	B-Application
for	O
every	O
pair	O
of	O
hosts	O
that	O
it	O
synchronizes	O
.	O
</s>
<s>
Common	O
features	O
of	O
file	B-Application
synchronization	I-Application
systems	O
include	O
:	O
</s>
<s>
Encryption	O
for	O
security	B-Application
,	O
especially	O
when	O
synchronizing	O
across	O
the	O
Internet	O
.	O
</s>
<s>
Compressing	B-General_Concept
any	O
data	O
sent	O
across	O
a	O
network	O
.	O
</s>
<s>
Conflict	B-Application
detection	I-Application
where	O
a	O
file	B-Application
has	O
been	O
modified	O
on	O
both	O
sources	O
,	O
as	O
opposed	O
to	O
where	O
it	O
has	O
only	O
been	O
modified	O
on	O
one	O
.	O
</s>
<s>
Undetected	O
conflicts	O
can	O
lead	O
to	O
overwriting	O
copies	O
of	O
the	O
file	B-Application
with	O
the	O
most	O
recent	O
version	O
,	O
causing	O
data	O
loss	O
.	O
</s>
<s>
For	O
conflict	B-Application
detection	I-Application
,	O
the	O
synchronization	O
software	O
needs	O
to	O
keep	O
a	O
database	O
of	O
the	O
synchronized	O
files	O
.	O
</s>
<s>
Distributed	O
conflict	B-Application
detection	I-Application
can	O
be	O
achieved	O
by	O
version	B-Operating_System
vectors	I-Operating_System
.	O
</s>
<s>
Open	O
Files	O
Support	O
ensures	O
data	O
integrity	O
when	O
copying	O
data	O
or	O
application	O
files	O
that	O
are	O
in-use	O
or	O
database	O
files	O
that	O
are	O
exclusively	O
locked	B-Application
.	O
</s>
<s>
Backup	B-Application
between	O
operating	O
systems	O
and	O
transfer	O
between	O
network	O
computers	O
.	O
</s>
<s>
Consumer-grade	O
file	B-Application
synchronization	I-Application
solutions	O
are	O
popular	O
,	O
however	O
for	O
business	O
use	O
,	O
they	O
create	O
a	O
concern	O
of	O
allowing	O
corporate	O
information	O
to	O
sprawl	O
to	O
unmanaged	O
devices	O
and	O
cloud	O
services	O
which	O
are	O
uncontrolled	O
by	O
the	O
organization	O
.	O
</s>
