<s>
In	O
computing	O
,	O
a	O
shared	B-General_Concept
resource	I-General_Concept
,	O
or	O
network	B-General_Concept
share	I-General_Concept
,	O
is	O
a	O
computer	B-General_Concept
resource	I-General_Concept
made	O
available	O
from	O
one	O
host	B-Device
to	O
other	O
hosts	O
on	O
a	O
computer	B-Architecture
network	I-Architecture
.	O
</s>
<s>
Network	O
sharing	O
is	O
made	O
possible	O
by	O
inter-process	B-Operating_System
communication	I-Operating_System
over	O
the	O
network	O
.	O
</s>
<s>
Some	O
examples	O
of	O
shareable	O
resources	O
are	O
computer	B-Application
programs	I-Application
,	O
data	B-General_Concept
,	O
storage	B-General_Concept
devices	I-General_Concept
,	O
and	O
printers	O
.	O
</s>
<s>
shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
(	O
also	O
known	O
as	O
disk	B-General_Concept
sharing	I-General_Concept
and	O
folder	B-General_Concept
sharing	I-General_Concept
)	O
,	O
shared	O
printer	O
access	O
,	O
shared	O
scanner	O
access	O
,	O
etc	O
.	O
</s>
<s>
The	O
term	O
file	O
sharing	O
traditionally	O
means	O
shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
,	O
especially	O
in	O
the	O
context	O
of	O
operating	B-General_Concept
systems	I-General_Concept
and	O
LAN	B-General_Concept
and	O
Intranet	B-General_Concept
services	O
,	O
for	O
example	O
in	O
Microsoft	B-Application
Windows	I-Application
documentation	O
.	O
</s>
<s>
Though	O
,	O
as	O
BitTorrent	B-Protocol
and	O
similar	O
applications	O
became	O
available	O
in	O
the	O
early	O
2000s	O
,	O
the	O
term	O
file	O
sharing	O
increasingly	O
has	O
become	O
associated	O
with	O
peer-to-peer	O
file	O
sharing	O
over	O
the	O
Internet	O
.	O
</s>
<s>
Shared	O
file	O
and	O
printer	O
access	O
require	O
an	O
operating	B-General_Concept
system	I-General_Concept
on	O
the	O
client	O
that	O
supports	O
access	O
to	O
resources	O
on	O
a	O
server	O
,	O
an	O
operating	B-General_Concept
system	I-General_Concept
on	O
the	O
server	O
that	O
supports	O
access	O
to	O
its	O
resources	O
from	O
a	O
client	O
,	O
and	O
an	O
application	B-Application
layer	I-Application
(	O
in	O
the	O
four	O
or	O
five	O
layer	O
TCP/IP	B-Protocol
reference	I-Protocol
model	I-Protocol
)	O
file	O
sharing	O
protocol	O
and	O
transport	B-Architecture
layer	I-Architecture
protocol	O
to	O
provide	O
that	O
shared	B-General_Concept
access	I-General_Concept
.	O
</s>
<s>
Modern	O
operating	B-General_Concept
systems	I-General_Concept
for	O
personal	B-Device
computers	I-Device
include	O
distributed	B-Protocol
file	I-Protocol
systems	I-Protocol
that	O
support	O
file	O
sharing	O
,	O
while	O
hand-held	O
computing	O
devices	O
sometimes	O
require	O
additional	O
software	O
for	O
shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
.	O
</s>
<s>
Primary	O
operating	B-General_Concept
system	I-General_Concept
Application	B-Application
protocol	I-Application
Transport	B-Architecture
protocol	I-Architecture
Mac	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
SMB	B-Operating_System
,	O
Apple	B-Protocol
Filing	I-Protocol
Protocol	I-Protocol
TCP	B-Protocol
,	O
</s>
<s>
UDP	B-Protocol
MS-DOS	B-Application
,	O
Windows	B-Application
SMB	B-Operating_System
,	O
also	O
known	O
as	O
CIFS	B-Operating_System
TCP	B-Protocol
,	O
</s>
<s>
NBT	O
(	O
includes	O
UDP	B-Protocol
)	O
,	O
</s>
<s>
The	O
"	O
primary	O
operating	B-General_Concept
system	I-General_Concept
"	O
is	O
the	O
operating	B-General_Concept
system	I-General_Concept
on	O
which	O
the	O
file	O
sharing	O
protocol	O
in	O
question	O
is	O
most	O
commonly	O
used	O
.	O
</s>
<s>
On	O
Microsoft	B-Application
Windows	I-Application
,	O
a	O
network	B-General_Concept
share	I-General_Concept
is	O
provided	O
by	O
the	O
Windows	B-Application
network	O
component	O
"	O
File	O
and	O
Printer	O
Sharing	O
for	O
Microsoft	O
Networks	O
"	O
,	O
using	O
Microsoft	O
's	O
SMB	B-Operating_System
(	O
Server	B-Operating_System
Message	I-Operating_System
Block	I-Operating_System
)	O
protocol	O
.	O
</s>
<s>
Other	O
operating	B-General_Concept
systems	I-General_Concept
might	O
also	O
implement	O
that	O
protocol	O
;	O
for	O
example	O
,	O
Samba	B-Language
is	O
an	O
SMB	B-Operating_System
server	O
running	O
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
and	O
some	O
other	O
non-MS-DOS/non	O
-Windows	O
operating	B-General_Concept
systems	I-General_Concept
such	O
as	O
OpenVMS	B-Operating_System
.	O
</s>
<s>
Samba	B-Language
can	O
be	O
used	O
to	O
create	O
network	B-General_Concept
shares	I-General_Concept
which	O
can	O
be	O
accessed	O
,	O
using	O
SMB	B-Operating_System
,	O
from	O
computers	O
running	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
An	O
alternative	O
approach	O
is	O
a	O
shared	B-General_Concept
disk	I-General_Concept
file	O
system	O
,	O
where	O
each	O
computer	O
has	O
access	O
to	O
the	O
"	O
native	O
"	O
filesystem	O
on	O
a	O
shared	B-General_Concept
disk	I-General_Concept
drive	O
.	O
</s>
<s>
Shared	B-General_Concept
resource	I-General_Concept
access	O
can	O
also	O
be	O
implemented	O
with	O
Web-based	B-Protocol
Distributed	I-Protocol
Authoring	I-Protocol
and	I-Protocol
Versioning	I-Protocol
(	O
WebDAV	B-Protocol
)	O
.	O
</s>
<s>
The	O
share	O
can	O
be	O
accessed	O
by	O
client	O
computers	O
through	O
some	O
naming	O
convention	O
,	O
such	O
as	O
UNC	O
(	O
Universal	O
Naming	O
Convention	O
)	O
used	O
on	O
DOS	B-Device
and	O
Windows	B-Application
PC	I-Application
computers	O
.	O
</s>
<s>
This	O
implies	O
that	O
a	O
network	B-General_Concept
share	I-General_Concept
can	O
be	O
addressed	O
according	O
to	O
the	O
following	O
:	O
</s>
<s>
where	O
is	O
the	O
WINS	B-Device
name	O
,	O
DNS	B-Protocol
name	I-Protocol
or	O
IP	B-Protocol
address	I-Protocol
of	O
the	O
server	O
computer	O
,	O
and	O
may	O
be	O
a	O
folder	B-Application
or	O
file	O
name	O
,	O
or	O
its	O
path	B-Application
.	O
</s>
<s>
The	O
shared	B-General_Concept
folder	I-General_Concept
can	O
also	O
be	O
given	O
a	O
ShareName	O
that	O
is	O
different	O
from	O
the	O
folder	B-Application
local	O
name	O
at	O
the	O
server	O
side	O
.	O
</s>
<s>
For	O
example	O
,	O
usually	O
denotes	O
a	O
drive	O
with	O
drive	O
letter	O
C	O
:	O
on	O
a	O
Windows	B-Application
machine	O
.	O
</s>
<s>
A	O
shared	B-General_Concept
drive	I-General_Concept
or	O
folder	B-Application
is	O
often	O
mapped	O
at	O
the	O
client	O
PC	O
computer	O
,	O
meaning	O
that	O
it	O
is	O
assigned	O
a	O
drive	O
letter	O
on	O
the	O
local	O
PC	O
computer	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
drive	O
letter	O
H	O
:	O
is	O
typically	O
used	O
for	O
the	O
user	O
home	O
directory	B-Application
on	O
a	O
central	O
file	B-Application
server	I-Application
.	O
</s>
<s>
A	O
network	B-General_Concept
share	I-General_Concept
can	O
become	O
a	O
security	O
liability	O
when	O
access	O
to	O
the	O
shared	O
files	O
is	O
gained	O
(	O
often	O
by	O
devious	O
means	O
)	O
by	O
those	O
who	O
should	O
not	O
have	O
access	O
to	O
them	O
.	O
</s>
<s>
Many	O
computer	O
worms	O
have	O
spread	O
through	O
network	B-General_Concept
shares	I-General_Concept
.	O
</s>
<s>
Network	B-General_Concept
shares	I-General_Concept
would	O
consume	O
extensive	O
communication	O
capacity	O
in	O
non-broadband	O
network	O
access	O
.	O
</s>
<s>
Because	O
of	O
that	O
,	O
shared	O
printer	O
and	O
file	O
access	O
is	O
normally	O
prohibited	O
in	O
firewalls	B-Application
from	O
computers	O
outside	O
the	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
or	O
enterprise	O
Intranet	B-General_Concept
.	O
</s>
<s>
However	O
,	O
by	O
means	O
of	O
virtual	B-Application
private	I-Application
networks	I-Application
(	O
VPN	B-Application
)	O
,	O
shared	B-General_Concept
resources	I-General_Concept
can	O
securely	O
be	O
made	O
available	O
for	O
certified	O
users	O
outside	O
the	O
local	B-General_Concept
network	I-General_Concept
.	O
</s>
<s>
A	O
network	B-General_Concept
share	I-General_Concept
is	O
typically	O
made	O
accessible	O
to	O
other	O
users	O
by	O
marking	O
any	O
folder	B-Application
or	O
file	O
as	O
shared	O
,	O
or	O
by	O
changing	O
the	O
file	O
system	O
permissions	O
or	O
access	O
rights	O
in	O
the	O
properties	O
of	O
the	O
folder	B-Application
.	O
</s>
<s>
For	O
example	O
,	O
a	O
file	O
or	O
folder	B-Application
may	O
be	O
accessible	O
only	O
to	O
one	O
user	O
(	O
the	O
owner	O
)	O
,	O
to	O
system	O
administrators	O
,	O
to	O
a	O
certain	O
group	O
of	O
users	O
to	O
public	O
,	O
i.e.	O
</s>
<s>
In	O
operating	B-General_Concept
system	I-General_Concept
editions	O
for	O
homes	O
and	O
small	O
offices	O
,	O
there	O
may	O
be	O
a	O
special	O
pre-shared	O
folder	O
that	O
is	O
accessible	O
to	O
all	O
users	O
with	O
a	O
user	O
account	O
and	O
password	O
on	O
the	O
local	O
computer	O
.	O
</s>
<s>
In	O
the	O
English	O
version	O
of	O
the	O
Windows	B-Application
XP	O
Home	O
Edition	O
operating	B-General_Concept
system	I-General_Concept
,	O
the	O
preshared	O
folder	B-Application
is	O
named	O
Shared	B-General_Concept
documents	I-General_Concept
,	O
typically	O
with	O
the	O
path	B-Application
.	O
</s>
<s>
In	O
Windows	B-Application
Vista	I-Application
and	O
Windows	B-Device
7	I-Device
,	O
the	O
pre-shared	O
folder	O
is	O
named	O
Public	O
documents	O
,	O
typically	O
with	O
the	O
path	B-Application
.Katy	O
Ivens	O
,	O
Networking	O
for	O
dummies	O
,	O
4th	O
edition	O
,	O
2007	O
,	O
page	O
121	O
.	O
</s>
<s>
In	O
home	O
and	O
small	O
office	O
networks	O
,	O
a	O
decentralized	B-Operating_System
approach	O
is	O
often	O
used	O
,	O
where	O
every	O
user	O
may	O
make	O
their	O
local	O
folders	O
and	O
printers	O
available	O
to	O
others	O
.	O
</s>
<s>
This	O
approach	O
is	O
sometimes	O
denoted	O
a	O
Workgroup	B-Device
or	O
peer-to-peer	O
network	O
topology	O
,	O
since	O
the	O
same	O
computer	O
may	O
be	O
used	O
as	O
client	O
as	O
well	O
as	O
server	O
.	O
</s>
<s>
In	O
large	O
enterprise	B-General_Concept
networks	I-General_Concept
,	O
a	O
centralized	O
file	B-Application
server	I-Application
or	O
print	B-Application
server	I-Application
,	O
sometimes	O
denoted	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
paradigm	I-Operating_System
,	O
is	O
typically	O
used	O
.	O
</s>
<s>
Online	B-General_Concept
storage	I-General_Concept
on	O
a	O
server	O
outside	O
the	O
local	B-General_Concept
network	I-General_Concept
is	O
currently	O
an	O
option	O
,	O
especially	O
for	O
homes	O
and	O
small	O
office	O
networks	O
.	O
</s>
<s>
Shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
should	O
not	O
be	O
confused	O
with	O
file	O
transfer	O
using	O
the	O
file	B-Protocol
transfer	I-Protocol
protocol	I-Protocol
(	O
FTP	O
)	O
,	O
or	O
the	O
Bluetooth	B-Protocol
IRDA	O
OBject	B-General_Concept
EXchange	I-General_Concept
(	O
OBEX	B-General_Concept
)	O
protocol	O
.	O
</s>
<s>
Shared	B-General_Concept
access	I-General_Concept
involves	O
automatic	O
synchronization	O
of	O
folder	B-Application
information	O
whenever	O
a	O
folder	B-Application
is	O
changed	O
on	O
the	O
server	O
,	O
and	O
may	O
provide	O
server	O
side	O
file	O
searching	O
,	O
while	O
file	O
transfer	O
is	O
a	O
more	O
rudimentary	O
service	O
.	O
</s>
<s>
Shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
is	O
normally	O
considered	O
as	O
a	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
(	O
LAN	B-General_Concept
)	O
service	O
,	O
while	O
FTP	O
is	O
an	B-Architecture
Internet	I-Architecture
service	O
.	O
</s>
<s>
Shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
is	O
transparent	O
to	O
the	O
user	O
,	O
as	O
if	O
it	O
was	O
a	O
resource	O
in	O
the	O
local	O
file	O
system	O
,	O
and	O
supports	O
a	O
multi-user	O
environment	O
.	O
</s>
<s>
This	O
includes	O
concurrency	B-Operating_System
control	I-Operating_System
or	O
locking	B-Operating_System
of	O
a	O
remote	O
file	O
while	O
a	O
user	O
is	O
editing	O
it	O
,	O
and	O
file	O
system	O
permissions	O
.	O
</s>
<s>
Shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
involves	O
but	O
should	O
not	O
be	O
confused	O
with	O
file	B-Application
synchronization	I-Application
and	O
other	O
information	O
synchronization	O
.	O
</s>
<s>
Internet-based	O
information	O
synchronization	O
may	O
,	O
for	O
example	O
,	O
use	O
the	O
SyncML	B-General_Concept
language	O
.	O
</s>
<s>
Shared	B-General_Concept
file	I-General_Concept
access	I-General_Concept
is	O
based	O
on	O
server-side	O
pushing	O
of	O
folder	B-Application
information	O
,	O
and	O
is	O
normally	O
used	O
over	O
an	O
"	O
always	O
on	O
"	O
Internet	B-Protocol
socket	I-Protocol
.	O
</s>
<s>
File	B-Application
synchronization	I-Application
allows	O
the	O
user	O
to	O
be	O
offline	O
from	O
time	O
to	O
time	O
and	O
is	O
normally	O
based	O
on	O
an	O
agent	O
software	O
that	O
polls	O
synchronized	O
machines	O
at	O
reconnect	O
,	O
and	O
sometimes	O
repeatedly	O
with	O
a	O
certain	O
time	O
interval	O
,	O
to	O
discover	O
differences	O
.	O
</s>
<s>
Modern	O
operating	B-General_Concept
systems	I-General_Concept
often	O
include	O
a	O
local	O
cache	B-Protocol
of	O
remote	O
files	O
,	O
allowing	O
offline	O
access	O
and	O
synchronization	O
when	O
reconnected	O
.	O
</s>
<s>
The	O
first	O
international	O
heterogenous	O
network	O
for	O
resource	B-General_Concept
sharing	I-General_Concept
was	O
the	O
1973	O
interconnection	O
of	O
the	O
ARPANET	O
with	O
early	O
British	O
academic	O
networks	O
through	O
the	O
computer	O
science	O
department	O
at	O
University	O
College	O
London	O
(	O
UCL	O
)	O
.	O
</s>
