<s>
Nonvolatile	B-Device
BIOS	I-Device
memory	I-Device
refers	O
to	O
a	O
small	O
memory	B-General_Concept
on	O
PC	B-Device
motherboards	I-Device
that	O
is	O
used	O
to	O
store	O
BIOS	B-Operating_System
settings	I-Operating_System
.	O
</s>
<s>
It	O
is	O
traditionally	O
called	O
CMOS	B-Device
RAM	I-Device
because	O
it	O
uses	O
a	O
volatile	B-General_Concept
,	O
low-power	O
complementary	O
metal	O
–	O
oxide	O
–	O
semiconductor	O
(	O
CMOS	B-Device
)	O
SRAM	B-Architecture
(	O
such	O
as	O
the	O
Motorola	O
MC146818	O
or	O
similar	O
)	O
powered	O
by	O
a	O
small	O
"	O
CMOS	B-Device
"	O
battery	O
when	O
system	O
and	O
standby	O
power	O
is	O
off	O
.	O
</s>
<s>
It	O
is	O
referred	O
to	O
as	O
non-volatile	O
memory	O
or	O
NVRAM	B-General_Concept
because	O
,	O
after	O
the	O
system	O
loses	O
power	O
,	O
it	O
does	O
retain	O
state	O
by	O
virtue	O
of	O
the	O
CMOS	B-Device
battery	O
.	O
</s>
<s>
The	O
typical	O
NVRAM	B-General_Concept
capacity	O
is	O
256	O
bytes	B-Application
.	O
</s>
<s>
The	O
CMOS	B-Device
RAM	I-Device
and	O
the	O
real-time	O
clock	O
have	O
been	O
integrated	O
as	O
a	O
part	O
of	O
the	O
southbridge	B-Device
chipset	O
and	O
it	O
may	O
not	O
be	O
a	O
standalone	O
chip	O
on	O
modern	O
motherboards	B-Device
.	O
</s>
<s>
In	O
turn	O
,	O
the	O
southbridge	B-Device
have	O
been	O
integrated	O
into	O
a	O
single	O
Platform	B-Device
Controller	I-Device
Hub	I-Device
.	O
</s>
<s>
Today	O
's	O
UEFI	B-Architecture
motherboards	B-Device
use	O
NVRAM	B-General_Concept
to	O
store	O
configuration	O
data	O
(	O
NVRAM	B-General_Concept
is	O
a	O
part	O
of	O
the	O
UEFI	B-Architecture
flash	O
ROM	O
)	O
,	O
but	O
by	O
many	O
OEMs	O
 '	O
design	O
,	O
the	O
UEFI	B-Architecture
settings	O
are	O
still	O
lost	O
if	O
the	O
CMOS	B-Device
battery	O
fails	O
.	O
</s>
<s>
The	O
memory	B-General_Concept
battery	O
(	O
aka	O
motherboard	B-Device
,	O
CMOS	B-Device
,	O
real-time	O
clock	O
(	O
RTC	O
)	O
,	O
clock	O
battery	O
)	O
is	O
generally	O
a	O
CR2032	B-Algorithm
lithium	O
coin	B-Algorithm
cell	I-Algorithm
.	O
</s>
<s>
Motherboards	B-Device
have	O
circuitry	O
preventing	O
batteries	O
from	O
being	O
charged	O
and	O
discharged	O
when	O
a	O
motherboard	B-Device
is	O
powered	O
on	O
.	O
</s>
<s>
Other	O
common	O
battery	O
cell	O
types	O
can	O
last	O
significantly	O
longer	O
or	O
shorter	O
periods	O
,	O
such	O
as	O
the	O
smaller	O
CR2016	B-Algorithm
which	O
will	O
generally	O
last	O
about	O
40%	O
less	O
time	O
than	O
CR2032	B-Algorithm
.	O
</s>
<s>
When	O
replacing	O
the	O
battery	O
cell	O
,	O
the	O
system	O
time	O
and	O
CMOS	B-Device
BIOS	B-Operating_System
settings	I-Operating_System
may	O
revert	O
to	O
default	O
values	O
.	O
</s>
<s>
Unwanted	O
BIOS	B-Operating_System
reset	O
may	O
be	O
avoided	O
by	O
replacing	O
the	O
battery	O
cell	O
with	O
the	O
PSU	O
power	O
switch	O
turned	O
on	O
and	O
plugged	O
into	O
an	O
electric	O
wall	O
socket	O
.	O
</s>
<s>
On	O
ATX	B-Language
motherboards	B-Device
,	O
the	O
PSU	O
will	O
supply	O
5V	O
standby	O
power	O
to	O
the	O
motherboard	B-Device
to	O
keep	O
CMOS	B-Device
memory	I-Device
energized	O
while	O
the	O
system	O
is	O
off	O
.	O
</s>
<s>
Some	O
computer	O
designs	O
have	O
used	O
non-button	O
cell	O
batteries	O
,	O
such	O
as	O
the	O
cylindrical	O
"	O
1/2	O
AA	O
"	O
used	O
in	O
the	O
Power	B-Device
Mac	I-Device
G4	I-Device
as	O
well	O
as	O
some	O
older	O
IBM	O
PC	B-Device
compatibles	O
,	O
or	O
a	O
3-cell	O
nickel	O
–	O
cadmium	O
(	O
Ni	O
–	O
Cd	O
)	O
CMOS	B-Device
battery	O
that	O
looks	O
like	O
a	O
"	O
barrel	O
"	O
(	O
common	O
in	O
Amiga	B-Device
and	O
older	O
IBM	O
PC	B-Device
compatibles	O
)	O
,	O
which	O
serves	O
the	O
same	O
purpose	O
.	O
</s>
<s>
These	O
motherboards	B-Device
often	O
have	O
a	O
four	O
pin	O
straight	O
header	O
,	O
with	O
pin	O
2	O
missing	O
,	O
for	O
connecting	O
to	O
an	O
external	O
3.6v	O
battery	O
,	O
such	O
as	O
the	O
Tadiran	O
TL-5242/W	O
,	O
when	O
their	O
soldered-on	O
batteries	O
run	O
out	O
.	O
</s>
