<s>
An	O
HTTP	B-Application
server	I-Application
is	O
a	O
computer	O
(	O
software	O
)	O
program	B-Application
(	O
or	O
even	O
a	O
software	O
component	O
included	O
in	O
an	O
other	O
program	B-Application
)	O
that	O
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
by	O
implementing	O
the	O
server	B-Application
part	O
of	O
the	O
HTTP	B-Protocol
and/or	O
HTTPS	B-Protocol
network	O
protocol(s )	O
.	O
</s>
<s>
An	O
HTTP	B-Application
server	I-Application
waits	O
for	O
the	O
incoming	O
client	O
requests	O
(	O
sent	O
by	O
user	B-Protocol
agents	I-Protocol
like	O
browsers	B-Application
,	O
web	B-Application
crawlers	I-Application
,	O
etc	O
.	O
)	O
</s>
<s>
and	O
for	O
each	O
request	O
it	O
answers	O
by	O
replying	O
with	O
requested	O
information	O
,	O
including	O
the	O
sending	O
of	O
the	O
requested	O
web	O
resource	O
,	O
or	O
with	O
an	O
HTTP	B-Protocol
error	I-Protocol
message	I-Protocol
.	O
</s>
<s>
An	O
HTTP	B-Application
server	I-Application
may	O
also	O
have	O
bindings	O
to	O
manage	O
protocol	O
extensions	O
to	O
HTTP	B-Protocol
(	O
i.e.	O
</s>
<s>
WebDAV	B-Protocol
,	O
etc	O
.	O
)	O
</s>
<s>
or	O
messages	O
of	O
other	O
protocols	O
enveloped	O
into	O
HTTP	B-Protocol
messages	O
(	O
i.e.	O
</s>
<s>
SOAP	B-Application
,	O
etc	O
.	O
)	O
</s>
<s>
in	O
order	O
to	O
allow	O
program-to-program	O
communications	O
.	O
</s>
<s>
Implementations	O
of	O
an	O
HTTP	B-Application
server	I-Application
may	O
vary	O
in	O
complexity	O
,	O
from	O
a	O
manageable	O
tiny	O
component	O
to	O
a	O
full	O
featured	O
program	B-Application
implementation	O
of	O
HTTP	B-Protocol
and	O
other	O
protocols	O
,	O
which	O
maybe	O
can	O
run	O
in	O
background	O
,	O
as	O
one	O
or	O
more	O
processes	O
,	O
etc	O
.	O
</s>
<s>
An	O
HTTP	B-Application
server	I-Application
can	O
be	O
found	O
in	O
any	O
kind	O
of	O
computer	O
,	O
including	O
embedded	B-Architecture
systems	I-Architecture
and	O
super	B-Architecture
computers	I-Architecture
,	O
also	O
because	O
it	O
is	O
a	O
required	O
component	O
to	O
run	O
web	O
interfaces	O
(	O
web	B-Application
applications	I-Application
)	O
,	O
etc	O
.	O
</s>
<s>
The	O
difference	O
between	O
the	O
term	O
web	B-Application
server	I-Application
and	O
the	O
term	O
HTTP	B-Application
server	I-Application
is	O
very	O
subtle	O
because	O
the	O
two	O
terms	O
are	O
almost	O
synonyms	O
.	O
</s>
<s>
The	O
first	O
term	O
(	O
web	B-Application
server	I-Application
)	O
somehow	O
predates	O
the	O
second	O
one	O
and	O
it	O
refers	O
to	O
the	O
purpose	O
of	O
serving	O
web	O
content	O
in	O
the	O
context	O
of	O
a	O
World	O
Wide	O
Web	O
environment	O
which	O
is	O
oriented	O
to	O
the	O
interaction	O
with	O
human	O
beings	O
.	O
</s>
<s>
That	O
term	O
may	O
refer	O
not	O
only	O
to	O
the	O
HTTP	B-Application
server	I-Application
software	O
component	O
but	O
also	O
to	O
the	O
whole	O
system	O
(	O
hardware	B-Architecture
and	O
software	O
)	O
required	O
to	O
run	O
a	O
website	O
.	O
</s>
<s>
The	O
second	O
term	O
(	O
HTTP	B-Application
server	I-Application
)	O
has	O
a	O
technical	O
origin	O
bound	O
to	O
the	O
software	O
implementation	O
of	O
the	O
server	B-Application
part	O
of	O
the	O
protocol	O
and	O
so	O
that	O
term	O
is	O
used	O
more	O
to	O
refer	O
to	O
it	O
as	O
a	O
software	O
component	O
which	O
can	O
be	O
used	O
for	O
many	O
other	O
purposes	O
besides	O
hosting	O
public	O
websites	O
in	O
Internet	O
or	O
even	O
private	O
websites	O
in	O
Intranets	B-General_Concept
or	O
Extranets	B-Architecture
.	O
</s>
