<s>
An	O
FTP	B-Protocol
server	I-Protocol
is	O
computer	O
software	O
consisting	O
of	O
one	O
or	O
more	O
programs	O
that	O
can	O
execute	O
commands	O
given	O
by	O
remote	O
client(s )	O
such	O
as	O
receiving	O
,	O
sending	O
,	O
deleting	O
files	O
,	O
creating	O
or	O
removing	O
directories	B-Application
,	O
etc	O
.	O
</s>
<s>
The	O
software	O
may	O
run	O
as	O
a	O
software	O
component	O
of	O
a	O
program	B-Application
,	O
as	O
a	O
standalone	O
program	B-Application
or	O
even	O
as	O
one	O
or	O
more	O
processes	O
(	O
in	O
the	O
background	O
)	O
.	O
</s>
<s>
An	O
FTP	B-Protocol
server	I-Protocol
plays	O
the	O
role	O
of	O
a	O
server	B-Application
in	O
a	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
model	I-Operating_System
using	O
the	O
FTP	B-Protocol
and/or	O
the	O
FTPS	B-Protocol
and/or	O
the	O
SFTP	B-Protocol
network	O
protocol(s )	O
.	O
</s>
<s>
An	O
FTP	B-Protocol
server	I-Protocol
can	O
also	O
be	O
intended	O
as	O
a	O
computer	O
that	O
runs	O
an	O
FTP	B-Protocol
server	I-Protocol
program	B-Application
to	O
host	O
collections	O
of	O
files	O
.	O
</s>
<s>
Big	O
FTP	B-Protocol
sites	I-Protocol
can	O
be	O
run	O
by	O
many	O
computers	O
in	O
order	O
to	O
be	O
able	O
to	O
serve	O
the	O
desired	O
maximum	O
number	O
of	O
clients	O
connected	O
to	O
servers	O
.	O
</s>
<s>
A	O
client	B-Protocol
program	I-Protocol
connects	O
to	O
an	O
FTP	B-Protocol
server	I-Protocol
,	O
then	O
,	O
unless	O
anonymous	O
access	O
is	O
enabled	O
,	O
it	O
has	O
to	O
authenticate	O
itself	O
by	O
sending	O
username	O
and	O
password	O
;	O
after	O
that	O
it	O
can	O
retrieve	O
and/or	O
send	O
files	O
to	O
the	O
server	B-Application
along	O
with	O
other	O
operations	O
(	O
depending	O
on	O
user	O
's	O
privileges	O
)	O
.	O
</s>
