<s>
In	O
optical	B-General_Concept
storage	I-General_Concept
,	O
constant	B-Device
angular	I-Device
velocity	I-Device
(	O
CAV	O
)	O
is	O
a	O
qualifier	O
for	O
the	O
rated	O
speed	O
of	O
any	O
disc	B-Device
containing	O
information	O
,	O
and	O
may	O
also	O
be	O
applied	O
to	O
the	O
writing	O
speed	O
of	O
recordable	O
discs	B-Device
.	O
</s>
<s>
A	O
drive	O
or	O
disc	B-Device
operating	O
in	O
CAV	O
mode	O
maintains	O
a	O
constant	B-Device
angular	I-Device
velocity	I-Device
,	O
contrasted	O
with	O
a	O
constant	B-Device
linear	I-Device
velocity	I-Device
(	O
CLV	O
)	O
.	O
</s>
<s>
A	O
typical	O
CD-ROM	O
drive	O
operates	O
in	O
CLV	O
mode	O
,	O
in	O
contrast	O
to	O
a	O
floppy	O
or	O
hard	B-Device
disk	I-Device
drive	I-Device
,	O
or	O
gramophone	O
,	O
which	O
operates	O
in	O
CAV	O
mode	O
.	O
</s>
<s>
In	O
CAV	O
mode	O
,	O
the	O
spindle	O
motor	O
turns	O
at	O
a	O
constant	O
speed	O
,	O
which	O
makes	O
the	O
medium	O
pass	O
by	O
the	O
read/write	B-Device
head	I-Device
faster	O
when	O
the	O
head	O
is	O
positioned	O
at	O
the	O
outside	O
of	O
the	O
disk	B-Device
.	O
</s>
<s>
In	O
contrast	O
,	O
in	O
CLV	O
mode	O
,	O
the	O
spindle	O
motor	O
speed	O
varies	O
so	O
that	O
the	O
medium	O
passes	O
by	O
the	O
head	O
at	O
the	O
same	O
speed	O
regardless	O
of	O
where	O
on	O
the	O
disk	B-Device
the	O
head	O
is	O
positioned	O
.	O
</s>
<s>
If	O
the	O
disk	B-Device
is	O
recorded	O
at	O
the	O
same	O
areal	O
density	O
throughout	O
,	O
then	O
when	O
read	O
or	O
written	O
in	O
CAV	O
mode	O
,	O
the	O
data	O
rate	O
is	O
higher	O
for	O
the	O
outer	O
tracks	O
than	O
for	O
the	O
inner	O
tracks	O
,	O
whereas	O
in	O
CLV	O
mode	O
,	O
the	O
data	O
rate	O
is	O
the	O
same	O
everywhere	O
.	O
</s>
<s>
Another	O
advantage	O
is	O
that	O
a	O
device	O
can	O
switch	O
from	O
reading	O
one	O
part	O
of	O
a	O
disk	B-Device
to	O
reading	O
another	O
part	O
more	O
quickly	O
,	O
because	O
in	O
CLV	O
mode	O
,	O
when	O
the	O
device	O
moves	O
the	O
head	O
in	O
or	O
out	O
,	O
it	O
must	O
change	O
the	O
speed	O
of	O
the	O
disc	B-Device
.	O
</s>
<s>
In	O
case	O
of	O
a	O
12	O
cm	O
standard	O
diameter	O
disc	B-Device
,	O
data	O
at	O
the	O
outermost	O
edge	O
(	O
6	O
cm	O
from	O
center	O
)	O
is	O
accessed	O
at	O
2.4	O
times	O
the	O
speed	O
of	O
data	O
at	O
the	O
inner	O
edge	O
of	O
the	O
data-containing	O
program	O
area	O
(	O
2.5	O
cm	O
from	O
center	O
)	O
.	O
</s>
<s>
For	O
a	O
miniature	O
disc	B-Device
with	O
a	O
diameter	O
of	O
8	O
cm	O
(	O
radius	O
of	O
4	O
cm	O
)	O
,	O
the	O
speed	O
ratio	O
of	O
outer	O
to	O
inner	O
data	O
edge	O
is	O
1.6	O
.	O
</s>
<s>
This	O
means	O
that	O
,	O
for	O
example	O
,	O
if	O
a	O
disc	B-Device
is	O
accessed	O
at	O
a	O
constant	B-Device
angular	I-Device
velocity	I-Device
of	O
×24	O
,	O
the	O
equivalent	O
linear	O
velocity	O
is	O
×24	O
while	O
accessed	O
at	O
the	O
outermost	O
edge	O
of	O
the	O
data	O
area	O
while	O
being	O
×10	O
at	O
the	O
innermost	O
data	O
area	O
.	O
</s>
<s>
It	O
allows	O
for	O
shorter	O
access	B-General_Concept
times	I-General_Concept
because	O
the	O
rotation	O
speed	O
(	O
angular	O
velocity	O
)	O
does	O
not	O
need	O
to	O
be	O
changed	O
when	O
the	O
laser	O
seeks	O
across	O
the	O
disc	B-Device
,	O
similarly	O
to	O
the	O
magnetic	B-Device
head	I-Device
of	O
a	O
hard	B-Device
disk	I-Device
drive	I-Device
.	O
</s>
<s>
CD-R	O
,	O
DVD±R	O
,	O
BD-R	B-Operating_System
)	O
because	O
the	O
disc	B-Device
can	O
spin	O
at	O
the	O
highest	O
physically	O
possible	O
angular	O
speed	O
throughout	O
the	O
entire	O
writing	O
process	O
.	O
</s>
<s>
A	O
linear	O
(	O
data	O
reading	O
and	O
writing	O
)	O
speeds	O
of	O
2.4	O
times	O
higher	O
can	O
be	O
reached	O
at	O
the	O
outer	O
disc	B-Device
edge	O
with	O
the	O
same	O
angular	O
(	O
rotation	O
)	O
speed	O
.	O
</s>
<s>
CAV	O
allowed	O
for	O
perfect	O
still	O
frames	O
,	O
as	O
well	O
as	O
random	O
access	O
to	O
any	O
given	O
frame	O
on	O
a	O
disc	B-Device
.	O
</s>
<s>
Playing	O
time	O
,	O
however	O
,	O
was	O
30	O
minutes	O
on	O
each	O
side	O
(	O
these	O
discs	B-Device
are	O
also	O
known	O
as	O
"	O
standard	O
play	O
"	O
)	O
,	O
as	O
opposed	O
to	O
60	O
minutes	O
on	O
each	O
side	O
for	O
CLV-based	O
discs	B-Device
(	O
"	O
extended	O
play	O
"	O
)	O
.	O
</s>
<s>
CAV	O
is	O
used	O
with	O
the	O
Nintendo	B-Device
GameCube	I-Device
Game	I-Device
disc	I-Device
and	I-Device
Wii	I-Device
Optical	I-Device
disc	I-Device
,	O
the	B-Application
original	I-Application
Xbox	I-Application
discs	B-Device
,	O
and	O
Sega	O
's	O
GD-ROM	B-Device
.	O
</s>
<s>
DVD-RAM	O
variants	O
)	O
has	O
a	O
linear	O
(	O
writing	O
)	O
speed	O
limitation	O
that	O
can	O
not	O
be	O
attained	O
with	O
physically	O
supported	O
angular	O
(	O
rotation	O
)	O
speeds	O
at	O
the	O
inner	O
edge	O
of	O
the	O
recordable	O
area	O
,	O
the	O
disc	B-Device
writing	O
can	O
start	O
off	O
with	O
a	O
constant	B-Device
angular	I-Device
velocity	I-Device
,	O
until	O
the	O
increasing	O
linear	O
velocity	O
has	O
reached	O
the	O
writing	O
speed	O
limitation	O
of	O
the	O
disc	B-Device
.	O
</s>
<s>
At	O
that	O
point	O
,	O
the	O
drive	O
transitions	O
into	O
writing	O
with	O
a	O
constant	B-Device
linear	I-Device
velocity	I-Device
.	O
</s>
