<s>
Funky	B-General_Concept
caching	I-General_Concept
is	O
the	O
generation	O
,	O
display	O
and	O
storage	O
of	O
dynamic	O
content	O
when	O
a	O
requested	O
static	O
web	O
page	O
resource	O
is	O
n't	O
available	O
.	O
</s>
<s>
The	O
name	O
is	O
based	O
on	O
the	O
idea	O
of	O
treating	O
the	O
web	O
server	O
,	O
serving	O
static	O
pages	O
,	O
as	O
a	O
cache	B-Protocol
.	O
</s>
<s>
However	O
,	O
unlike	O
common	O
reverse	O
caches	O
,	O
the	O
funky	O
cache	B-Protocol
is	O
part	O
of	O
the	O
web	O
server	O
software	O
,	O
and	O
has	O
the	O
ability	O
to	O
dynamically	O
generate	O
this	O
content	O
.	O
</s>
<s>
If	O
they	O
are	O
not	O
,	O
the	O
conventional	O
HTTP	B-Protocol
404	I-Protocol
error	O
is	O
returned	O
,	O
as	O
usual	O
.	O
</s>
<s>
The	O
overall	O
advantage	O
is	O
relatively	O
small	O
,	O
compared	O
to	O
a	O
conventional	O
cache	B-Protocol
.	O
</s>
<s>
However	O
it	O
does	O
allow	O
small	O
sites	O
with	O
no	O
separate	O
cache	B-Protocol
layer	O
to	O
achieve	O
some	O
of	O
the	O
advantages	O
of	O
caching	O
(	O
albeit	O
a	O
little	O
inflexibly	O
)	O
.	O
</s>
<s>
This	O
is	O
why	O
it	O
became	O
popular	O
at	O
one	O
time	O
for	O
small	O
,	O
single-server	O
dynamic	O
web	O
sites	O
,	O
particularly	O
those	O
built	O
within	O
the	O
PHP	B-Application
community	O
,	O
where	O
the	O
technique	O
originated	O
.	O
</s>
<s>
It	O
is	O
also	O
known	O
as	O
the	O
ErrorDocument	O
trick	O
,	O
Smarter	O
Caching	O
and	O
Rasmus	O
 '	O
Trick	O
,	O
the	O
latter	O
name	O
in	O
honor	O
of	O
Rasmus	O
Lerdorf	O
,	O
creator	O
of	O
the	O
PHP	B-Application
programming	I-Application
language	I-Application
,	O
who	O
was	O
allegedly	O
the	O
first	O
to	O
present	O
this	O
mechanism	O
(	O
though	O
it	O
is	O
also	O
attributed	O
to	O
Stig	O
Bakken	O
)	O
.	O
</s>
<s>
One	O
common	O
usage	O
is	O
the	O
replacement	O
of	O
the	O
HTTP	B-Protocol
Error404	I-Protocol
ErrorDocument	O
with	O
a	O
dynamic	O
script	O
.	O
</s>
<s>
Another	O
way	O
to	O
look	O
at	O
it	O
as	O
a	O
variation	O
of	O
the	O
cache-aside	O
pattern	O
where	O
,	O
instead	O
of	O
reading	O
the	O
data	O
from	O
the	O
data	O
store	O
,	O
it	O
is	O
generated	O
dynamically	O
,	O
and	O
where	O
the	O
implementation	O
spans	O
an	O
architecture	O
(	O
in	O
this	O
case	O
the	O
Web	O
server	O
and	O
the	O
Web	O
app	O
language	O
)	O
instead	O
of	O
being	O
implemented	O
in	O
a	O
single	O
system	O
.	O
</s>
