<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
a	O
pool	O
is	O
a	O
collection	O
of	O
resources	B-General_Concept
that	O
are	O
kept	O
,	O
in	O
memory	O
,	O
ready	O
to	O
use	O
,	O
rather	O
than	O
the	O
memory	O
acquired	O
on	O
use	O
and	O
the	O
memory	O
released	O
afterwards	O
.	O
</s>
<s>
In	O
this	O
context	O
,	O
resources	B-General_Concept
can	O
refer	O
to	O
system	B-General_Concept
resources	I-General_Concept
such	O
as	O
file	B-Application
handles	I-Application
,	O
which	O
are	O
external	O
to	O
a	O
process	O
,	O
or	O
internal	O
resources	B-General_Concept
such	O
as	O
objects	O
.	O
</s>
<s>
A	O
pool	O
client	B-Protocol
requests	O
a	O
resource	O
from	O
the	O
pool	O
and	O
performs	O
desired	O
operations	O
on	O
the	O
returned	O
resource	O
.	O
</s>
<s>
When	O
the	O
client	B-Protocol
finishes	O
its	O
use	O
of	O
the	O
resource	O
,	O
it	O
is	O
returned	O
to	O
the	O
pool	O
rather	O
than	O
released	O
and	O
lost	O
.	O
</s>
<s>
The	O
pooling	O
of	O
resources	B-General_Concept
can	O
offer	O
a	O
significant	O
response-time	O
boost	O
in	O
situations	O
that	O
have	O
high	O
cost	O
associated	O
with	O
resource	O
acquiring	O
,	O
high	O
rate	O
of	O
the	O
requests	O
for	O
resources	B-General_Concept
,	O
and	O
a	O
low	O
overall	O
count	O
of	O
simultaneously	O
used	O
resources	B-General_Concept
.	O
</s>
<s>
Pooling	O
is	O
also	O
useful	O
when	O
the	O
latency	O
is	O
a	O
concern	O
,	O
because	O
a	O
pool	O
offers	O
predictable	O
times	O
required	O
to	O
obtain	O
resources	B-General_Concept
since	O
they	O
have	O
already	O
been	O
acquired	O
.	O
</s>
<s>
These	O
benefits	O
are	O
mostly	O
true	O
for	O
system	B-General_Concept
resources	I-General_Concept
that	O
require	O
a	O
system	B-Operating_System
call	I-Operating_System
,	O
or	O
remote	O
resources	B-General_Concept
that	O
require	O
a	O
network	O
communication	O
,	O
such	O
as	O
database	B-General_Concept
connections	I-General_Concept
,	O
socket	B-Protocol
connections	I-Protocol
,	O
threads	B-Operating_System
,	O
and	O
memory	B-General_Concept
allocation	I-General_Concept
.	O
</s>
<s>
Pooling	O
is	O
also	O
useful	O
for	O
expensive-to-compute	O
data	O
,	O
notably	O
large	O
graphic	O
objects	O
like	O
fonts	O
or	O
bitmaps	O
,	O
acting	O
essentially	O
as	O
a	O
data	O
cache	B-General_Concept
or	O
a	O
memoization	O
technique	O
.	O
</s>
<s>
Special	O
cases	O
of	O
pools	O
are	O
connection	B-General_Concept
pools	I-General_Concept
,	O
thread	B-Operating_System
pools	I-Operating_System
,	O
and	O
memory	B-General_Concept
pools	I-General_Concept
.	O
</s>
<s>
Pools	O
can	O
also	O
be	O
used	O
for	O
objects	O
,	O
in	O
which	O
context	O
a	O
pool	O
refers	O
to	O
a	O
design	O
pattern	O
for	O
implementing	O
pools	O
in	O
object-oriented	B-Language
languages	I-Language
,	O
such	O
as	O
in	O
the	O
object	O
pool	O
pattern	O
.	O
</s>
<s>
Objects	O
themselves	O
hold	O
no	O
external	O
resources	B-General_Concept
and	O
only	O
occupy	O
memory	O
,	O
although	O
an	O
already	O
created	O
object	O
avoids	O
the	O
memory	B-General_Concept
allocation	I-General_Concept
required	O
on	O
object	O
creation	O
.	O
</s>
