<s>
A	O
computer	B-General_Concept
case	I-General_Concept
,	O
also	O
known	O
as	O
a	O
computer	B-General_Concept
chassis	I-General_Concept
,	O
is	O
the	O
enclosure	O
that	O
contains	O
most	O
of	O
the	O
hardware	B-Architecture
of	O
a	O
personal	B-Device
computer	I-Device
.	O
</s>
<s>
The	O
components	O
housed	O
inside	O
the	O
case	O
(	O
such	O
as	O
the	O
CPU	B-Device
,	O
motherboard	B-Device
,	O
memory	B-General_Concept
,	O
mass	B-Device
storage	I-Device
devices	I-Device
,	O
power	O
supply	O
unit	O
and	O
various	O
expansion	B-Device
cards	I-Device
)	O
are	O
referred	O
as	O
the	O
internal	O
hardware	B-Architecture
,	O
while	O
hardware	B-Architecture
outside	O
the	O
case	O
(	O
typically	O
cable-linked	O
or	O
plug-and-play	B-Device
devices	O
such	O
as	O
the	O
display	B-Device
,	O
speakers	O
,	O
keyboard	B-Device
,	O
mouse	B-Device
and	O
USB	B-Protocol
flash	O
drives	O
)	O
are	O
known	O
as	O
peripherals	O
.	O
</s>
<s>
Conventional	O
computer	B-General_Concept
cases	I-General_Concept
are	O
fully	O
enclosed	O
,	O
with	O
small	O
holes	O
(	O
mostly	O
in	O
the	O
back	O
panel	O
)	O
that	O
allow	O
ventilation	O
and	O
cutout	O
openings	O
that	O
provide	O
access	O
to	O
plugs/sockets	O
(	O
back	O
)	O
and	O
removable	B-Device
media	I-Device
drive	B-Device
bays	I-Device
(	O
front	O
)	O
.	O
</s>
<s>
The	O
structural	O
frame	O
(	O
chassis	O
)	O
of	O
a	O
case	O
is	O
usually	O
constructed	O
from	O
rigid	O
metals	O
such	O
as	O
steel	O
(	O
often	O
SECC	O
—	O
steel	O
,	O
electrogalvanized	O
,	O
cold-rolled	O
,	O
coil	O
)	O
and	O
aluminium	O
alloy	O
,	O
with	O
hardpoints	O
and	O
through	O
holes	O
for	O
mounting	O
internal	O
hardware	B-Architecture
,	O
case	O
fans/coolers	O
and	O
for	O
organizing	O
cable	O
management	O
.	O
</s>
<s>
The	O
external	O
case	O
panels	O
,	O
at	B-Device
least	O
one	O
of	O
which	O
are	O
removable	O
,	O
cover	O
the	O
chassis	O
from	O
the	O
front	O
,	O
sides	O
and	O
top	O
to	O
shield	O
the	O
internal	O
components	O
from	O
physical	O
intrusion	O
and	O
dust	O
collection	O
,	O
and	O
are	O
typically	O
made	O
from	O
painted	O
metallic	O
and/or	O
plastic	O
material	O
,	O
while	O
other	O
materials	O
such	O
as	O
mesh	B-Algorithm
,	O
tempered	O
glass	O
,	O
acrylic	O
,	O
wood	O
and	O
even	O
Lego	O
bricks	O
have	O
appeared	O
in	O
many	O
modern	O
commercial	O
or	O
home-built	B-Architecture
cases	I-Architecture
.	O
</s>
<s>
In	O
recent	O
years	O
,	O
open	O
frame	O
or	O
open	O
air	O
cases	O
that	O
are	O
only	O
partly	O
enclosed	O
(	O
with	O
freer	O
ventilation	O
and	O
thus	O
theoretically	O
better	O
cooling	B-General_Concept
)	O
have	O
become	O
available	O
in	O
the	O
premium	O
gaming	B-Device
PC	I-Device
market	O
.	O
</s>
<s>
Cases	O
can	O
come	O
in	O
many	O
different	O
sizes	O
and	O
shapes	O
,	O
which	O
are	O
usually	O
determined	O
by	O
the	O
form	O
factor	O
of	O
the	O
motherboard	B-Device
since	O
it	O
is	O
physically	O
the	O
largest	O
hardware	B-Architecture
component	O
in	O
most	O
computers	O
.	O
</s>
<s>
Consequently	O
,	O
personal	B-Device
computer	I-Device
form	O
factors	O
typically	O
specify	O
only	O
the	O
internal	O
dimensions	O
and	O
layout	O
of	O
the	O
case	O
.	O
</s>
<s>
Form	O
factors	O
for	O
rack-mounted	B-Application
and	O
blade	B-Architecture
servers	I-Architecture
may	O
include	O
precise	O
external	O
dimensions	O
as	O
well	O
since	O
these	O
cases	O
must	O
themselves	O
fit	O
in	O
specific	O
enclosures	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
case	O
designed	O
for	O
an	O
ATX	B-Language
motherboard	B-Device
and	O
power	O
supply	O
unit	O
(	O
PSU	O
)	O
may	O
take	O
on	O
several	O
external	O
forms	O
such	O
as	O
a	O
vertical	O
tower	O
(	O
designed	O
to	O
sit	O
on	O
the	O
floor	O
,	O
height	O
>	O
width	O
)	O
,	O
a	O
flat	O
desktop	O
(	O
height	O
<	O
width	O
)	O
or	O
pizza	B-General_Concept
box	I-General_Concept
(	O
height	O
≤	O
)	O
designed	O
to	O
sit	O
on	O
the	O
desk	O
under	O
the	O
computer	O
's	O
monitor	B-Device
)	O
.	O
</s>
<s>
Full-size	O
tower	B-General_Concept
cases	I-General_Concept
are	O
typically	O
larger	O
in	O
volume	O
than	O
desktop	B-General_Concept
cases	I-General_Concept
,	O
with	O
more	O
room	O
for	O
drive	B-Device
bays	I-Device
,	O
expansion	B-Device
slots	I-Device
,	O
and	O
custom	O
or	O
all-in-one	O
(	O
AIO	O
)	O
water	O
cooling	B-General_Concept
solutions	O
.	O
</s>
<s>
Desktop	B-General_Concept
cases	I-General_Concept
—	O
and	O
mini-tower	O
cases	O
under	O
about	O
high	O
—	O
are	O
popular	O
in	O
business	O
environments	O
where	O
space	O
is	O
at	B-Device
a	O
premium	O
.	O
</s>
<s>
Currently	O
,	O
the	O
most	O
popular	O
form	O
factor	O
for	O
desktop	B-Device
computers	I-Device
is	O
ATX	B-Language
,	O
although	O
microATX	O
and	O
small	B-Device
form	I-Device
factors	I-Device
have	O
also	O
become	O
very	O
popular	O
for	O
a	O
variety	O
of	O
uses	O
.	O
</s>
<s>
In	O
the	O
high-end	O
segment	O
,	O
the	O
unofficial	O
and	O
loosely	O
defined	O
XL-ATX	O
specification	O
appeared	O
around	O
2009	O
.	O
</s>
<s>
It	O
extends	O
the	O
length	O
of	O
the	O
mainboard	B-Device
to	O
accommodate	O
four	O
graphics	O
cards	O
with	O
dual-slot	O
coolers	O
.	O
</s>
<s>
Some	O
XL-ATX	O
mainboards	B-Device
increase	O
the	O
mainboard	B-Device
's	O
width	O
as	O
well	O
,	O
to	O
allow	O
more	O
space	O
for	O
the	O
CPU	B-Device
,	O
Memory	B-General_Concept
PWM	O
,	O
and	O
in	O
some	O
cases	O
,	O
a	O
second	O
CPU	B-Device
socket	O
.	O
</s>
<s>
While	O
the	O
market	O
share	O
of	O
these	O
exotic	O
high-end	O
mainboards	B-Device
is	O
very	O
low	O
,	O
almost	O
all	O
high-end	O
cases	O
and	O
many	O
mainstream	O
cases	O
support	O
XL-ATX	O
(	O
10	O
expansion	B-Device
slots	I-Device
)	O
.	O
</s>
<s>
As	O
of	O
2018	O
,	O
no	O
major	O
motherboard	B-Device
manufacturer	O
has	O
made	O
an	O
XL-ATX	O
board	O
for	O
several	O
years	O
.	O
</s>
<s>
E-ATX	O
is	O
similar	O
to	O
XL-ATX	O
in	O
that	O
it	O
is	O
larger	O
than	O
ATX	B-Language
and	O
is	O
also	O
loosely	O
defined	O
.	O
</s>
<s>
Unlike	O
XL-ATX	O
,	O
E-ATX	O
motherboards	B-Device
and	O
cases	O
are	O
still	O
in	O
production	O
(	O
as	O
of	O
2020	O
)	O
,	O
and	O
support	O
quad-channel	O
memory	B-General_Concept
across	O
8	O
slots	O
of	O
ram	O
,	O
up	O
to	O
4	O
PCI-e	O
expansion	B-Device
slots	I-Device
for	O
up	O
to	O
4	O
double	O
slot	O
graphics	O
cards	O
and	O
a	O
single	O
CPU	B-Device
such	O
as	O
the	O
AMD	O
Ryzen	O
Threadripper	O
3990X	O
.	O
</s>
<s>
Companies	O
like	O
In	O
Win	O
Development	O
,	O
Shuttle	O
Inc	O
.	O
and	O
AOpen	O
originally	O
popularized	O
small	O
cases	O
,	O
for	O
which	O
FlexATX	B-Device
was	O
the	O
most	O
common	O
motherboard	B-Device
size	O
.	O
</s>
<s>
As	O
of	O
2010	O
Mini	B-Architecture
ITX	I-Architecture
has	O
widely	O
replaced	O
FlexATX	B-Device
as	O
the	O
most	O
common	O
small	B-Device
form	I-Device
factor	I-Device
mainboard	B-Device
standard	O
.	O
</s>
<s>
The	O
latest	O
mini	B-Architecture
ITX	I-Architecture
mainboards	B-Device
from	O
Asus	O
,	O
Gigabyte	O
,	O
MSI	O
,	O
ASRock	O
,	O
Zotac	O
and	O
Foxconn	O
offer	O
the	O
same	O
feature	O
set	O
as	O
full	O
size	O
mainboards	B-Device
.	O
</s>
<s>
High-end	O
mini	B-Architecture
ITX	I-Architecture
mainboards	B-Device
support	O
standard	O
desktop	O
CPUs	B-Device
,	O
use	O
standard	O
memory	B-General_Concept
DIMM	O
sockets	O
,	O
and	O
mostly	O
feature	O
a	O
full-size	O
PCI-E	O
16×	O
slot	O
with	O
support	O
for	O
the	O
fastest	O
graphics	O
cards	O
,	O
although	O
some	O
instead	O
use	O
a	O
PCI	O
,	O
or	O
PCIe	O
slot	O
of	O
fewer	O
than	O
16	O
lanes	O
.	O
</s>
<s>
Apple	O
Inc	O
.	O
has	O
also	O
produced	O
the	O
Mac	B-Device
Mini	I-Device
computer	O
,	O
which	O
is	O
similar	O
in	O
size	O
to	O
a	O
standard	O
CD-ROM	B-Device
drive	O
,	O
and	O
many	O
manufacturers	O
offer	O
mini-ITX	B-Architecture
cases	O
of	O
similar	O
size	O
for	O
low-wattage	O
CPUs	B-Device
with	O
integrated	O
graphics	O
.	O
</s>
<s>
Tower	B-General_Concept
cases	I-General_Concept
are	O
often	O
categorized	O
as	O
mini-tower	O
,	O
midi-tower	O
,	O
mid-tower	O
,	O
or	O
full-tower	O
.	O
</s>
<s>
Full	O
tower	B-General_Concept
cases	I-General_Concept
are	O
typically	O
or	O
more	O
in	O
height	O
and	O
intended	O
to	O
stand	O
on	O
the	O
floor	O
.	O
</s>
<s>
They	O
can	O
have	O
anywhere	O
from	O
six	O
to	O
ten	O
externally	O
accessible	O
drive	B-Device
bays	I-Device
.	O
</s>
<s>
The	O
full	O
tower	B-General_Concept
case	I-General_Concept
was	O
originally	O
developed	O
to	O
house	O
file	B-Application
servers	I-Application
which	O
would	O
typically	O
be	O
tasked	O
with	O
serving	O
data	O
from	O
expensive	O
CD-ROM	B-Device
databases	O
that	O
held	O
more	O
data	O
than	O
the	O
hard	B-Device
drives	I-Device
commonly	O
available	O
at	B-Device
the	O
time	O
.	O
</s>
<s>
Hence	O
,	O
many	O
full	O
tower	B-General_Concept
cases	I-General_Concept
include	O
locking	O
doors	O
and	O
other	O
physical	O
security	O
features	O
to	O
prevent	O
theft	O
of	O
the	O
discs	O
.	O
</s>
<s>
However	O
,	O
as	O
computing	O
technology	O
moves	O
from	O
floppy	B-Device
disks	I-Device
and	O
CD-ROMs	B-Device
to	O
large	O
capacity	O
hard	B-Device
drives	I-Device
,	O
USB	B-Protocol
flash	O
drives	O
,	O
and	O
network-based	O
solutions	O
,	O
more	O
recent	O
full	O
tower	B-General_Concept
cases	I-General_Concept
typically	O
only	O
have	O
none	O
,	O
one	O
,	O
or	O
two	O
external	O
bays	O
for	O
CD	O
drives	O
,	O
with	O
the	O
internal	O
bays	O
moved	O
elsewhere	O
in	O
the	O
case	O
to	O
improve	O
airflow	O
.	O
</s>
<s>
Today	O
,	O
full	O
tower	B-General_Concept
cases	I-General_Concept
are	O
commonly	O
used	O
by	O
enthusiasts	O
as	O
showpiece	O
display	B-Device
cases	O
with	O
custom	O
water	O
cooling	B-General_Concept
,	O
lighting	O
,	O
and	O
tempered	O
glass	O
(	O
replacing	O
acrylic	O
)	O
.	O
</s>
<s>
Computer	B-General_Concept
cases	I-General_Concept
usually	O
include	O
sheet	O
metal	O
enclosures	O
for	O
a	O
power	O
supply	O
unit	O
and	O
drive	B-Device
bays	I-Device
,	O
as	O
well	O
as	O
a	O
rear	O
panel	O
that	O
can	O
accommodate	O
peripheral	O
connectors	O
protruding	O
from	O
the	O
motherboard	B-Device
and	O
expansion	B-Device
slots	I-Device
.	O
</s>
<s>
Most	O
cases	O
also	O
have	O
a	O
power	O
button	O
or	O
switch	O
,	O
a	O
reset	B-Application
button	I-Application
,	O
and	O
LEDs	O
to	O
indicate	O
power	O
,	O
hard	B-Device
drive	I-Device
activity	O
,	O
and	O
network	O
activity	O
in	O
some	O
models	O
.	O
</s>
<s>
Some	O
cases	O
include	O
built-in	O
I/O	B-Architecture
ports	I-Architecture
(	O
such	O
as	O
USB	B-Protocol
and	O
headphone	O
ports	O
)	O
on	O
the	O
front	O
of	O
the	O
case	O
.	O
</s>
<s>
Such	O
a	O
case	O
will	O
also	O
(	O
normally	O
)	O
include	O
the	O
wires	O
needed	O
to	O
connect	O
these	O
ports	O
,	O
switches	O
,	O
and	O
indicators	O
to	O
the	O
motherboard	B-Device
.	O
</s>
<s>
The	O
motherboard	B-Device
is	O
usually	O
screwed	O
to	O
the	O
case	O
along	O
its	O
largest	O
face	O
,	O
which	O
could	O
be	O
the	O
bottom	O
or	O
the	O
side	O
of	O
the	O
case	O
depending	O
on	O
the	O
form	O
factor	O
and	O
orientation	O
.	O
</s>
<s>
Form	O
factors	O
such	O
as	O
ATX	B-Language
provide	O
a	O
back	O
panel	O
with	O
cut-out	O
holes	O
to	O
expose	O
I/O	B-Architecture
ports	I-Architecture
provided	O
by	O
integrated	O
peripherals	O
,	O
as	O
well	O
as	O
expansion	B-Device
slots	I-Device
which	O
may	O
optionally	O
expose	O
additional	O
ports	O
provided	O
by	O
expansion	B-Device
cards	I-Device
.	O
</s>
<s>
Many	O
larger	O
ATX	B-Language
cases	O
can	O
also	O
be	O
used	O
with	O
motherboards	B-Device
of	O
other	O
form	O
factors	O
.	O
</s>
<s>
The	O
power	O
supply	O
unit	O
mounting	O
point	O
differs	O
from	O
case	O
to	O
case	O
,	O
but	O
the	O
most	O
commonly	O
used	O
locations	O
(	O
both	O
at	B-Device
the	O
rear	O
of	O
the	O
case	O
)	O
and	O
their	O
advantages/disadvantages	O
are	O
:	O
</s>
<s>
Most	O
cases	O
include	O
drive	B-Device
bays	I-Device
on	O
the	O
front	O
of	O
the	O
case	O
;	O
a	O
typical	O
ATX	B-Language
case	O
includes	O
5.25	B-Device
"	I-Device
,	O
3.5	B-Device
"	I-Device
and	O
2.5	O
"	O
bays	O
.	O
</s>
<s>
In	O
modern	O
computers	O
,	O
the	O
5.25	B-Device
"	I-Device
bays	O
are	O
used	O
for	O
optical	O
drives	O
,	O
the	O
3.5	B-Device
"	I-Device
bays	I-Device
are	O
used	O
for	O
hard	B-Device
drives	I-Device
and	O
card	B-Device
readers	I-Device
,	O
and	O
the	O
2.5	O
"	O
bays	O
are	O
used	O
for	O
solid-state	B-Device
drives	I-Device
.	O
</s>
<s>
Buttons	O
and	O
LEDs	O
are	O
typically	O
located	O
on	O
the	O
front	O
of	O
the	O
case	O
;	O
some	O
cases	O
include	O
additional	O
I/O	B-Architecture
ports	I-Architecture
,	O
temperature	O
,	O
and	O
processor	O
speed	O
monitors	O
in	O
the	O
same	O
area	O
.	O
</s>
<s>
Larger	O
vents	O
usually	O
allow	O
cooling	B-Application
fans	I-Application
to	O
be	O
mounted	O
via	O
surrounding	O
threaded	O
screw	O
holes	O
.	O
</s>
<s>
Newer	O
cases	O
include	O
mountings	O
for	O
larger	O
120mm	O
or	O
140mm	O
cooling	B-Application
fans	I-Application
for	O
quieter	O
operation	O
than	O
the	O
80mm	O
fans	O
formerly	O
common	O
.	O
</s>
<s>
An	O
I/O	O
template	O
,	O
or	O
I/O	O
plate	O
,	O
fits	O
around	O
the	O
motherboard	B-Device
's	O
back	O
panel	O
of	O
external	O
ports	O
.	O
</s>
<s>
Sometimes	O
provided	O
by	O
the	O
case	O
manufacturer	O
,	O
it	O
is	O
often	O
replaced	O
by	O
the	O
one	O
that	O
comes	O
with	O
the	O
motherboard	B-Device
.	O
</s>
<s>
Accessing	O
the	O
interior	O
components	O
of	O
a	O
modern	O
ATX	B-Language
tower	B-General_Concept
case	I-General_Concept
is	O
done	O
by	O
removing	O
the	O
side	O
panels	O
.	O
</s>
<s>
Looking	O
front-to-back	O
,	O
accessing	O
the	O
motherboard	B-Device
,	O
PSU	O
,	O
drive	B-Device
bays	I-Device
,	O
and	O
most	O
case	B-Application
fan	I-Application
installation	O
points	O
are	O
done	O
by	O
removing	O
the	O
left	O
side	O
panel	O
.	O
</s>
<s>
Removing	O
the	O
right-side	O
panel	O
is	O
done	O
less	O
often	O
to	O
access	O
the	O
space	O
behind	O
the	O
motherboard	B-Device
mounting	O
plate	O
.	O
</s>
<s>
This	O
space	O
is	O
devoted	O
to	O
cable	O
management	O
,	O
as	O
cables	O
routed	O
in	O
front	O
of	O
the	O
motherboard	B-Device
may	O
disrupt	O
the	O
flow	O
of	O
air	O
within	O
the	O
case	O
causing	O
increased	O
temperatures	O
.	O
</s>
<s>
BTX	B-Device
,	O
an	O
uncontemporary	O
standard	O
,	O
has	O
the	O
main	O
side	O
panel	O
on	O
the	O
right	O
side	O
as	O
opposed	O
to	O
the	O
left	O
.	O
</s>
<s>
Some	O
upside-down	O
designed	O
ATX	B-Language
cases	O
are	O
also	O
accessed	O
by	O
removing	O
the	O
right-side	O
panel	O
door	O
.	O
</s>
<s>
This	O
was	O
ubiquitous	O
in	O
AT	B-Device
tower	B-General_Concept
cases	I-General_Concept
.	O
</s>
<s>
Traditionally	O
,	O
most	O
computer	B-General_Concept
cases	I-General_Concept
required	O
computer	B-General_Concept
case	I-General_Concept
screws	I-General_Concept
to	O
hold	O
components	O
and	O
panels	O
in	O
place	O
(	O
i.e.	O
</s>
<s>
motherboard	B-Device
,	O
PSU	O
,	O
drives	O
,	O
and	O
expansion	B-Device
cards	I-Device
)	O
.	O
</s>
<s>
From	O
the	O
early	O
2000s	O
onwards	O
there	O
is	O
a	O
trend	O
towards	O
tool-less	O
cases	O
,	O
in	O
which	O
components	O
are	O
held	O
together	O
with	O
snap-in	O
plastic	O
rails	O
,	O
thumbscrews	O
,	O
and	O
other	O
methods	O
that	O
do	O
not	O
require	O
tools	O
;	O
this	O
facilitates	O
quick	O
assembly	O
and	O
modification	O
of	O
computer	B-Architecture
hardware	I-Architecture
and	O
is	O
also	O
cheaper	O
to	O
manufacture	O
.	O
</s>
<s>
Throughout	O
the	O
1990s	O
,	O
most	O
computer	B-General_Concept
cases	I-General_Concept
had	O
simple	O
rectangular	O
shapes	O
,	O
and	O
were	O
often	O
painted	O
beige	O
or	O
white	O
with	O
little	O
attention	O
given	O
to	O
the	O
visual	O
design	O
.	O
</s>
<s>
Beige	B-General_Concept
box	I-General_Concept
designs	O
are	O
still	O
found	O
on	O
a	O
large	O
number	O
of	O
budget	O
computers	O
assembled	O
from	O
generic	O
components	O
.	O
</s>
<s>
This	O
class	O
of	O
machines	O
is	O
still	O
known	O
as	O
white	B-General_Concept
box	I-General_Concept
computers	I-General_Concept
.	O
</s>
<s>
More	O
modern	O
computer	B-General_Concept
cases	I-General_Concept
include	O
a	O
much	O
wider	O
range	O
of	O
variation	O
in	O
shape	O
,	O
color	O
,	O
form	O
factor	O
,	O
and	O
materials	O
,	O
such	O
as	O
brushed	O
aluminium	O
and/or	O
tempered	O
glass	O
which	O
are	O
offered	O
with	O
more	O
expensive	O
cases	O
.	O
</s>
<s>
Case	B-Architecture
modding	I-Architecture
is	O
the	O
artistic	O
styling	O
of	O
computer	B-General_Concept
cases	I-General_Concept
,	O
often	O
to	O
draw	O
attention	O
to	O
the	O
use	O
of	O
advanced	O
or	O
unusual	O
components	O
.	O
</s>
<s>
Modded	O
cases	O
may	O
also	O
include	O
colored	O
internal	O
lighting	O
,	O
custom	O
paint	O
,	O
or	O
liquid	O
cooling	B-General_Concept
systems	O
.	O
</s>
<s>
Historically	O
,	O
cases	O
used	O
CCFL	O
lighting	O
and	O
eventually	O
single	O
color	O
LEDs	O
as	O
strips	O
or	O
in	O
fans	O
to	O
illuminate	O
their	O
interior	O
;	O
modern	O
cases	O
use	O
RGB	O
LED	O
lighting	O
instead	O
,	O
often	O
incorporated	O
into	O
case	B-Application
fans	I-Application
.	O
</s>
<s>
To	O
improve	O
airflow	O
while	O
allowing	O
RGB	O
fans	O
to	O
be	O
visible	O
,	O
many	O
cases	O
as	O
of	O
2020	O
use	O
metal	O
meshes	B-Algorithm
,	O
without	O
any	O
external	O
bays	O
.	O
</s>
<s>
Some	O
used	O
to	O
include	O
holes	O
to	O
support	O
external	O
water	O
cooling	B-General_Concept
radiators	O
.	O
</s>
<s>
Some	O
computer	B-General_Concept
cases	I-General_Concept
include	O
a	O
biased	O
switch	O
(	O
push-button	O
)	O
which	O
connects	O
to	O
the	O
motherboard	B-Device
.	O
</s>
<s>
The	O
system	O
's	O
firmware	B-Application
or	O
BIOS	B-Operating_System
may	O
be	O
configured	O
to	O
report	O
this	O
event	O
the	O
next	O
time	O
it	O
is	O
powered	O
on	O
.	O
</s>
<s>
In	O
the	O
past	O
,	O
many	O
tower	B-General_Concept
cases	I-General_Concept
intended	O
to	O
house	O
file	B-Application
servers	I-Application
featured	O
a	O
locking	O
door	O
covering	O
the	O
external	O
drive	B-Device
bays	I-Device
.	O
</s>
<s>
This	O
was	O
a	O
security	O
feature	O
intended	O
to	O
prevent	O
the	O
theft	O
of	O
the	O
CD-ROM	B-Device
discs	O
the	O
drives	O
would	O
be	O
holding	O
.	O
</s>
<s>
At	B-Device
the	O
time	O
,	O
CD-ROM	B-Device
capacity	O
was	O
larger	O
than	O
the	O
hard	B-Device
disks	I-Device
available	O
,	O
and	O
many	O
business-critical	O
databases	O
were	O
distributed	O
on	O
this	O
media	O
.	O
</s>
