<s>
The	O
compact	O
disc	O
(	O
CD	B-Device
)	O
is	O
a	O
digital	O
optical	B-Device
disc	I-Device
data	B-General_Concept
storage	I-General_Concept
format	O
that	O
was	O
co-developed	O
by	O
Philips	O
and	O
Sony	O
to	O
store	O
and	O
play	O
digital	O
audio	O
recordings	O
.	O
</s>
<s>
The	O
format	O
was	O
later	O
adapted	O
(	O
as	O
CD-ROM	B-Device
)	O
for	O
general-purpose	O
data	B-General_Concept
storage	I-General_Concept
.	O
</s>
<s>
Several	O
other	O
formats	O
were	O
further	O
derived	O
,	O
including	O
write-once	O
audio	O
and	O
data	B-General_Concept
storage	I-General_Concept
(	O
CD-R	O
)	O
,	O
rewritable	O
media	O
(	O
CD-RW	O
)	O
,	O
Video	O
CD	B-Device
(	O
VCD	O
)	O
,	O
Super	O
Video	O
CD	B-Device
(	O
SVCD	O
)	O
,	O
Photo	O
CD	B-Device
,	O
Picture	O
CD	B-Device
,	O
Compact	O
Disc-Interactive	O
(	O
CD-i	B-Device
)	O
and	O
Enhanced	B-Application
Music	I-Application
CD	I-Application
.	O
</s>
<s>
Standard	O
CDs	B-Device
have	O
a	O
diameter	O
of	O
and	O
are	O
designed	O
to	O
hold	O
up	O
to	O
74	B-Device
minutes	I-Device
of	O
uncompressed	O
stereo	O
digital	O
audio	O
or	O
about	O
650MiB	O
of	O
data	O
.	O
</s>
<s>
The	O
Mini	O
CD	B-Device
has	O
various	O
diameters	O
ranging	O
from	O
;	O
they	O
are	O
sometimes	O
used	O
for	O
CD	B-Device
singles	O
,	O
storing	O
up	O
to	O
24	O
minutes	O
of	O
audio	O
,	O
or	O
delivering	O
device	B-Application
drivers	I-Application
.	O
</s>
<s>
At	O
the	O
time	O
of	O
the	O
technology	O
's	O
introduction	O
in	O
1982	O
,	O
a	O
CD	B-Device
could	O
store	O
much	O
more	O
data	O
than	O
a	O
personal	B-Device
computer	I-Device
hard	B-Device
disk	I-Device
drive	I-Device
,	O
which	O
would	O
typically	O
hold	O
10	O
MiB	O
.	O
</s>
<s>
By	O
2010	O
,	O
hard	B-Device
drives	I-Device
commonly	O
offered	O
as	O
much	O
storage	O
space	O
as	O
a	O
thousand	O
CDs	B-Device
,	O
while	O
their	O
prices	O
had	O
plummeted	O
to	O
commodity	O
levels	O
.	O
</s>
<s>
In	O
2004	O
,	O
worldwide	O
sales	O
of	O
audio	O
CDs	B-Device
,	O
CD-ROMs	B-Device
,	O
and	O
CD-Rs	O
reached	O
about	O
30	O
billion	O
discs	O
.	O
</s>
<s>
By	O
2007	O
,	O
200	O
billion	O
CDs	B-Device
had	O
been	O
sold	O
worldwide	O
.	O
</s>
<s>
A	O
CD	B-Device
is	O
made	O
from	O
thick	O
,	O
polycarbonate	O
plastic	O
,	O
and	O
weighs	O
14	O
–	O
33	O
grams	O
.	O
</s>
<s>
CD	B-Device
data	O
is	O
represented	O
as	O
tiny	O
indentations	O
known	O
as	O
pits	O
,	O
encoded	O
in	O
a	O
spiral	O
track	O
moulded	O
into	O
the	O
top	O
of	O
the	O
polycarbonate	O
layer	O
.	O
</s>
<s>
When	O
playing	O
an	O
audio	O
CD	B-Device
,	O
a	O
motor	O
within	O
the	O
CD	B-Device
player	I-Device
spins	O
the	O
disc	O
to	O
a	O
scanning	O
velocity	O
of	O
1.2	O
–	O
1.4m/s	O
(	O
constant	B-Device
linear	I-Device
velocity	I-Device
,	O
CLV	O
)	O
—	O
equivalent	O
to	O
approximately	O
500	O
RPM	O
at	O
the	O
inside	O
of	O
the	O
disc	O
,	O
and	O
approximately	O
200	O
RPM	O
at	O
the	O
outside	O
edge	O
.	O
</s>
<s>
The	O
track	O
on	O
the	O
CD	B-Device
begins	O
at	O
the	O
inside	O
and	O
spirals	O
outward	O
so	O
a	O
disc	O
played	O
from	O
beginning	O
to	O
end	O
slows	O
its	O
rotation	O
rate	O
during	O
playback	O
.	O
</s>
<s>
The	O
program	O
area	O
is	O
86.05cm2	O
and	O
the	O
length	O
of	O
the	O
recordable	O
spiral	O
is	O
With	O
a	O
scanning	O
speed	O
of	O
1.2m/s	O
,	O
the	O
playing	O
time	O
is	O
74	B-Device
minutes	I-Device
or	O
650MiB	O
of	O
data	O
on	O
a	O
CD-ROM	B-Device
.	O
</s>
<s>
A	O
CD	B-Device
is	O
read	O
by	O
focusing	O
a	O
780nm	O
wavelength	O
(	O
near	O
infrared	O
)	O
semiconductor	O
laser	O
through	O
the	O
bottom	O
of	O
the	O
polycarbonate	O
layer	O
.	O
</s>
<s>
To	O
accommodate	O
the	O
spiral	O
pattern	O
of	O
data	O
,	O
the	O
laser	O
is	O
placed	O
on	O
a	O
mobile	O
mechanism	O
within	O
the	O
disc	O
tray	O
of	O
any	O
CD	B-Device
player	I-Device
.	O
</s>
<s>
Some	O
CD	B-Device
drives	O
(	O
particularly	O
those	O
manufactured	O
by	O
Philips	O
during	O
the	O
1980s	O
and	O
early	O
1990s	O
)	O
use	O
a	O
swing	O
arm	O
similar	O
to	O
that	O
seen	O
on	O
a	O
gramophone	O
.	O
</s>
<s>
This	O
,	O
in	O
turn	O
,	O
is	O
decoded	O
by	O
reversing	O
the	O
eight-to-fourteen	B-Protocol
modulation	I-Protocol
used	O
in	O
mastering	O
the	O
disc	O
,	O
and	O
then	O
reversing	O
the	O
cross-interleaved	B-Error_Name
Reed	I-Error_Name
–	I-Error_Name
Solomon	I-Error_Name
coding	I-Error_Name
,	O
finally	O
revealing	O
the	O
raw	O
data	O
stored	O
on	O
the	O
disc	O
.	O
</s>
<s>
These	O
encoding	O
techniques	O
(	O
defined	O
in	O
the	O
Red	O
Book	O
)	O
were	O
originally	O
designed	O
for	O
CD	B-Device
Digital	O
Audio	O
,	O
but	O
they	O
later	O
became	O
a	O
standard	O
for	O
almost	O
all	O
CD	B-Device
formats	O
(	O
such	O
as	O
CD-ROM	B-Device
)	O
.	O
</s>
<s>
CDs	B-Device
are	O
susceptible	O
to	O
damage	O
during	O
handling	O
and	O
from	O
environmental	O
exposure	O
.	O
</s>
<s>
Consequently	O
,	O
CDs	B-Device
are	O
more	O
likely	O
to	O
suffer	O
damage	O
on	O
the	O
label	O
side	O
of	O
the	O
disc	O
.	O
</s>
<s>
The	O
edges	O
of	O
CDs	B-Device
are	O
sometimes	O
incompletely	O
sealed	O
,	O
allowing	O
gases	O
and	O
liquids	O
to	O
enter	O
the	O
CD	B-Device
and	O
corrode	O
the	O
metal	O
reflective	O
layer	O
and/or	O
interfere	O
with	O
the	O
focus	O
of	O
the	O
laser	O
on	O
the	O
pits	O
,	O
a	O
condition	O
known	O
as	O
disc	B-Device
rot	I-Device
.	O
</s>
<s>
The	O
fungus	O
Geotrichum	O
candidum	O
has	O
been	O
found	O
—	O
under	O
conditions	O
of	O
high	O
heat	O
and	O
humidity	O
—	O
to	O
consume	O
the	O
polycarbonate	O
plastic	O
and	O
aluminium	O
found	O
in	O
CDs	B-Device
.	O
</s>
<s>
The	O
data	O
integrity	O
of	O
compact	O
discs	O
can	O
be	O
measured	O
using	O
surface	O
error	O
scanning	O
,	O
which	O
can	O
measure	O
the	O
rates	O
of	O
different	O
types	O
of	O
data	O
errors	O
,	O
known	O
as	O
C1	O
,	O
C2	B-Device
,	O
CU	O
and	O
extended	O
(	O
finer-grain	O
)	O
error	O
measurements	O
known	O
as	O
E11	O
,	O
E12	O
,	O
E21	O
,	O
E22	O
,	O
E31	O
and	O
E32	O
,	O
of	O
which	O
higher	O
rates	O
indicate	O
a	O
possibly	O
damaged	O
or	O
unclean	O
data	O
surface	O
,	O
low	O
media	O
quality	O
,	O
deteriorating	B-Device
media	I-Device
and	O
recordable	B-General_Concept
media	I-General_Concept
written	O
to	O
by	O
a	O
malfunctioning	O
CD	B-Device
writer	O
.	O
</s>
<s>
Support	O
of	O
error	O
scanning	O
differs	O
between	O
vendors	O
and	O
models	O
of	O
optical	B-Device
disc	I-Device
drives	O
,	O
and	O
extended	O
error	O
scanning	O
(	O
known	O
as	O
"	O
advanced	O
error	O
scanning	O
"	O
in	O
Nero	O
DiscSpeed	O
)	O
has	O
only	O
been	O
available	O
on	O
Plextor	O
and	O
some	O
BenQ	O
optical	B-Device
drives	O
so	O
far	O
,	O
as	O
of	O
2020	O
.	O
</s>
<s>
The	O
digital	O
data	O
on	O
a	O
CD	B-Device
begins	O
at	O
the	O
center	O
of	O
the	O
disc	O
and	O
proceeds	O
toward	O
the	O
edge	O
,	O
which	O
allows	O
adaptation	O
to	O
the	O
different	O
sizes	O
available	O
.	O
</s>
<s>
Standard	O
CDs	B-Device
are	O
available	O
in	O
two	O
sizes	O
.	O
</s>
<s>
This	O
is	O
a	O
myth	O
according	O
to	O
Kees	O
Immink	O
,	O
as	O
the	O
EFM	B-Protocol
code	O
format	O
had	O
not	O
yet	O
been	O
decided	O
in	O
December	O
1979	O
,	O
when	O
the	O
120mm	O
size	O
was	O
adopted	O
.	O
</s>
<s>
The	O
adoption	O
of	O
EFM	B-Protocol
in	O
June	O
1980	O
allowed	O
30	O
percent	O
more	O
playing	O
time	O
that	O
would	O
have	O
resulted	O
in	O
97	O
minutes	O
for	O
120mm	O
diameter	O
or	O
74	B-Device
minutes	I-Device
for	O
a	O
disc	O
as	O
small	O
as	O
.	O
</s>
<s>
Instead	O
,	O
however	O
,	O
the	O
information	O
density	O
was	O
lowered	O
by	O
30	O
percent	O
to	O
keep	O
the	O
playing	O
time	O
at	O
74	B-Device
minutes	I-Device
.	O
</s>
<s>
The	O
120mm	O
diameter	O
has	O
been	O
adopted	O
by	O
subsequent	O
formats	O
,	O
including	O
Super	O
Audio	O
CD	B-Device
,	O
DVD	O
,	O
HD	B-Operating_System
DVD	I-Operating_System
,	O
and	O
Blu-ray	O
Disc	O
.	O
</s>
<s>
The	O
diameter	O
discs	O
(	O
"	O
Mini	O
CDs	B-Device
"	O
)	O
can	O
hold	O
up	O
to	O
24	O
minutes	O
of	O
music	O
or	O
210MiB	O
.	O
</s>
<s>
The	O
logical	O
format	O
of	O
an	O
audio	O
CD	B-Device
(	O
officially	O
Compact	O
Disc	O
Digital	O
Audio	O
or	O
CD-DA	O
)	O
is	O
described	O
in	O
a	O
document	O
produced	O
in	O
1980	O
by	O
the	O
format	O
's	O
joint	O
creators	O
,	O
Sony	O
and	O
Philips	O
.	O
</s>
<s>
The	O
document	O
is	O
known	O
colloquially	O
as	O
the	O
Red	O
Book	O
CD-DA	O
after	O
the	O
color	O
of	O
its	O
cover	O
.	O
</s>
<s>
The	O
format	O
is	O
a	O
two-channel	O
16-bit	O
PCM	B-Algorithm
encoding	O
at	O
a	O
44.1	O
kHz	O
sampling	O
rate	O
per	O
channel	O
.	O
</s>
<s>
Monaural	O
audio	O
has	O
no	O
existing	O
standard	O
on	O
a	O
Red	O
Book	O
CD	B-Device
;	O
thus	O
,	O
the	O
mono	O
source	O
material	O
is	O
usually	O
presented	O
as	O
two	O
identical	O
channels	O
in	O
a	O
standard	O
Red	O
Book	O
stereo	O
track	O
(	O
i.e.	O
,	O
mirrored	O
mono	O
)	O
;	O
an	O
MP3	B-Application
CD	B-Device
,	O
however	O
,	O
can	O
have	O
audio	O
file	O
formats	O
with	O
mono	O
sound	O
.	O
</s>
<s>
CD-Text	O
is	O
an	O
extension	O
of	O
the	O
Red	O
Book	O
specification	O
for	O
an	O
audio	O
CD	B-Device
that	O
allows	O
for	O
the	O
storage	O
of	O
additional	O
text	O
information	O
(	O
e.g.	O
,	O
album	O
name	O
,	O
song	O
name	O
,	O
artist	O
)	O
on	O
a	O
standards-compliant	O
audio	O
CD	B-Device
.	O
</s>
<s>
The	O
information	O
is	O
stored	O
either	O
in	O
the	O
lead-in	B-Application
area	I-Application
of	O
the	O
CD	B-Device
,	O
where	O
there	O
are	O
roughly	O
five	O
kilobytes	O
of	O
space	O
available	O
or	O
in	O
the	O
subcode	O
channels	O
R	O
to	O
W	O
on	O
the	O
disc	O
,	O
which	O
can	O
store	O
about	O
31	O
megabytes	O
.	O
</s>
<s>
The	O
disc	O
can	O
be	O
played	O
on	O
a	O
regular	O
audio	O
CD	B-Device
player	I-Device
,	O
but	O
when	O
played	O
on	O
a	O
special	O
CD+G	O
player	O
,	O
it	O
can	O
output	O
a	O
graphics	O
signal	O
(	O
typically	O
,	O
the	O
CD+G	O
player	O
is	O
hooked	O
up	O
to	O
a	O
television	O
set	O
or	O
a	O
computer	O
monitor	O
)	O
;	O
these	O
graphics	O
are	O
almost	O
exclusively	O
used	O
to	O
display	O
lyrics	O
on	O
a	O
television	O
set	O
for	O
karaoke	O
performers	O
to	O
sing	O
along	O
with	O
.	O
</s>
<s>
The	O
CD+G	O
format	O
takes	O
advantage	O
of	O
the	O
channels	O
R	O
through	O
W	O
.	O
These	O
six	O
bits	O
store	O
the	O
graphics	O
information	O
.	O
</s>
<s>
CD	B-Device
+	O
Extended	O
Graphics	O
(	O
CD+EG	O
,	O
also	O
known	O
as	O
CD+XG	O
)	O
is	O
an	O
improved	O
variant	O
of	O
the	O
Compact	O
Disc	O
+	O
Graphics	O
(	O
CD+G	O
)	O
format	O
.	O
</s>
<s>
Like	O
CD+G	O
,	O
CD+EG	O
uses	O
basic	O
CD-ROM	B-Device
features	O
to	O
display	O
text	O
and	O
video	O
information	O
in	O
addition	O
to	O
the	O
music	O
being	O
played	O
.	O
</s>
<s>
Very	O
few	O
,	O
if	O
any	O
,	O
CD+EG	O
discs	O
have	O
been	O
published	O
.	O
</s>
<s>
Super	O
Audio	O
CD	B-Device
(	O
SACD	O
)	O
is	O
a	O
high-resolution	O
,	O
read-only	O
optical	B-Device
audio	O
disc	O
format	O
that	O
was	O
designed	O
to	O
provide	O
higher-fidelity	O
digital	O
audio	O
reproduction	O
than	O
the	O
Red	O
Book	O
.	O
</s>
<s>
SACD	O
was	O
in	O
a	O
format	O
war	O
with	O
DVD-Audio	O
,	O
but	O
neither	O
has	O
replaced	O
audio	O
CDs	B-Device
.	O
</s>
<s>
Titles	O
in	O
the	O
SACD	O
format	O
can	O
be	O
issued	O
as	O
hybrid	O
discs	O
;	O
these	O
discs	O
contain	O
the	O
SACD	O
audio	O
stream	O
as	O
well	O
as	O
a	O
standard	O
audio	O
CD	B-Device
layer	O
which	O
is	O
playable	O
in	O
standard	O
CD	B-Device
players	I-Device
,	O
thus	O
making	O
them	O
backward	O
compatible	O
.	O
</s>
<s>
CD-MIDI	O
is	O
a	O
format	O
used	O
to	O
store	O
music-performance	O
data	O
,	O
which	O
upon	O
playback	O
is	O
performed	O
by	O
electronic	O
instruments	O
that	O
synthesize	O
the	O
audio	O
.	O
</s>
<s>
Hence	O
,	O
unlike	O
the	O
original	O
Red	O
Book	O
CD-DA	O
,	O
these	O
recordings	O
are	O
not	O
digitally	O
sampled	O
audio	O
recordings	O
.	O
</s>
<s>
The	O
CD-MIDI	O
format	O
is	O
defined	O
as	O
an	O
extension	O
of	O
the	O
original	O
Red	O
Book	O
.	O
</s>
<s>
For	O
the	O
first	O
few	O
years	O
of	O
its	O
existence	O
,	O
the	O
CD	B-Device
was	O
a	O
medium	O
used	O
purely	O
for	O
audio	O
.	O
</s>
<s>
However	O
,	O
in	O
1988	O
,	O
the	O
Yellow	B-Device
Book	I-Device
CD-ROM	B-Device
standard	O
was	O
established	O
by	O
Sony	O
and	O
Philips	O
,	O
which	O
defined	O
a	O
non-volatile	O
optical	B-Device
data	O
computer	B-General_Concept
data	I-General_Concept
storage	I-General_Concept
medium	O
using	O
the	O
same	O
physical	O
format	O
as	O
audio	O
compact	O
discs	O
,	O
readable	O
by	O
a	O
computer	O
with	O
a	O
CD-ROM	B-Device
drive	O
.	O
</s>
<s>
Video	O
CD	B-Device
(	O
VCD	O
,	O
View	O
CD	B-Device
,	O
and	O
Compact	O
Disc	O
digital	O
video	O
)	O
is	O
a	O
standard	O
digital	O
format	O
for	O
storing	O
video	O
media	O
on	O
a	O
CD	B-Device
.	O
</s>
<s>
VCDs	O
are	O
playable	O
in	O
dedicated	O
VCD	O
players	O
,	O
most	O
modern	O
DVD-Video	O
players	O
,	O
personal	B-Device
computers	I-Device
,	O
and	O
some	O
video	O
game	O
consoles	O
.	O
</s>
<s>
352×240	O
(	O
or	O
SIF	O
)	O
resolution	B-General_Concept
was	O
chosen	O
because	O
it	O
is	O
half	O
the	O
vertical	O
and	O
half	O
the	O
horizontal	O
resolution	B-General_Concept
of	O
the	O
NTSC	O
video	O
.	O
</s>
<s>
352×288	O
is	O
a	O
similarly	O
one-quarter	O
PAL/SECAM	O
resolution	B-General_Concept
.	O
</s>
<s>
This	O
approximates	O
the	O
(	O
overall	O
)	O
resolution	B-General_Concept
of	O
an	O
analog	O
VHS	O
tape	O
,	O
which	O
,	O
although	O
it	O
has	O
double	O
the	O
number	O
of	O
(	O
vertical	O
)	O
scan	O
lines	O
,	O
has	O
a	O
much	O
lower	O
horizontal	O
resolution	B-General_Concept
.	O
</s>
<s>
Super	O
Video	O
CD	B-Device
(	O
Super	O
Video	O
Compact	O
Disc	O
or	O
SVCD	O
)	O
is	O
a	O
format	O
used	O
for	O
storing	O
video	O
media	O
on	O
standard	O
compact	O
discs	O
.	O
</s>
<s>
SVCD	O
has	O
two-thirds	O
the	O
resolution	B-General_Concept
of	O
DVD	O
,	O
and	O
over	O
2.7	O
times	O
the	O
resolution	B-General_Concept
of	O
VCD	O
.	O
</s>
<s>
One	O
CD-R	O
disc	O
can	O
hold	O
up	O
to	O
60	O
minutes	O
of	O
standard-quality	O
SVCD-format	O
video	O
.	O
</s>
<s>
Photo	O
CD	B-Device
is	O
a	O
system	O
designed	O
by	O
Kodak	O
for	O
digitizing	O
and	O
storing	O
photos	O
on	O
a	O
CD	B-Device
.	O
</s>
<s>
Photo	O
CDs	B-Device
are	O
defined	O
in	O
the	O
Beige	O
Book	O
and	O
conform	O
to	O
the	O
CD-ROM	B-Device
XA	O
and	O
CD-i	B-Device
Bridge	O
specifications	O
as	O
well	O
.	O
</s>
<s>
They	O
are	O
intended	O
to	O
play	O
on	O
CD-i	B-Device
players	O
,	O
Photo	O
CD	B-Device
players	I-Device
,	O
and	O
any	O
computer	O
with	O
suitable	O
software	O
(	O
irrespective	O
of	O
operating	B-General_Concept
system	I-General_Concept
)	O
.	O
</s>
<s>
This	O
format	O
is	O
not	O
to	O
be	O
confused	O
with	O
Kodak	O
Picture	O
CD	B-Device
,	O
which	O
is	O
a	O
consumer	O
product	O
in	O
CD-ROM	B-Device
format	O
.	O
</s>
<s>
The	O
Philips	O
Green	B-Device
Book	I-Device
specifies	O
a	O
standard	O
for	O
interactive	O
multimedia	O
compact	O
discs	O
designed	O
for	O
CD-i	B-Device
players	O
(	O
1993	O
)	O
.	O
</s>
<s>
CD-i	B-Device
discs	O
can	O
contain	O
audio	O
tracks	O
that	O
can	O
be	O
played	O
on	O
regular	O
CD	B-Device
players	I-Device
,	O
but	O
CD-i	B-Device
discs	O
are	O
not	O
compatible	O
with	O
most	O
CD-ROM	B-Device
drives	O
and	O
software	O
.	O
</s>
<s>
The	O
CD-i	B-Device
Ready	O
specification	O
was	O
later	O
created	O
to	O
improve	O
compatibility	O
with	O
audio	O
CD	B-Device
players	I-Device
,	O
and	O
the	O
CD-i	B-Device
Bridge	O
specification	O
was	O
added	O
to	O
create	O
CD-i-compatible	O
discs	O
that	O
can	O
be	O
accessed	O
by	O
regular	O
CD-ROM	B-Device
drives	O
.	O
</s>
<s>
Philips	O
defined	O
a	O
format	O
similar	O
to	O
CD-i	B-Device
called	O
CD-i	B-Device
Ready	O
,	O
which	O
puts	O
CD-i	B-Device
software	O
and	O
data	O
into	O
the	O
pregap	O
of	O
track	O
1	O
.	O
</s>
<s>
This	O
format	O
was	O
supposed	O
to	O
be	O
more	O
compatible	O
with	O
older	O
audio	O
CD	B-Device
players	I-Device
.	O
</s>
<s>
Enhanced	B-Application
Music	I-Application
CD	I-Application
,	O
also	O
known	O
as	O
CD	B-Application
Extra	I-Application
or	O
CD	B-Device
Plus	O
,	O
is	O
a	O
format	O
that	O
combines	O
audio	O
tracks	O
and	O
data	B-Device
tracks	I-Device
on	O
the	O
same	O
disc	O
by	O
putting	O
audio	O
tracks	O
in	O
a	O
first	O
session	O
and	O
data	O
in	O
a	O
second	O
session	O
.	O
</s>
<s>
It	O
was	O
developed	O
by	O
Philips	O
and	O
Sony	O
,	O
and	O
it	O
is	O
defined	O
in	O
the	O
Blue	B-Application
Book	I-Application
.	O
</s>
<s>
VinylDisc	O
is	O
the	O
hybrid	O
of	O
a	O
standard	O
audio	O
CD	B-Device
and	O
the	O
vinyl	O
record	O
.	O
</s>
<s>
In	O
1995	O
,	O
material	O
costs	O
were	O
30	O
cents	O
for	O
the	O
jewel	O
case	O
and	O
10	O
to	O
15	O
cents	O
for	O
the	O
CD	B-Device
.	O
</s>
<s>
The	O
wholesale	O
cost	O
of	O
CDs	B-Device
was	O
$0.75	O
to	O
$1.15	O
,	O
while	O
the	O
typical	O
retail	O
price	O
of	O
a	O
prerecorded	O
music	O
CD	B-Device
was	O
$16.98	O
.	O
</s>
<s>
When	O
8-track	O
cartridges	O
,	O
compact	B-Device
cassettes	I-Device
,	O
and	O
CDs	B-Device
were	O
introduced	O
,	O
each	O
was	O
marketed	O
at	O
a	O
higher	O
price	O
than	O
the	O
format	O
they	O
succeeded	O
,	O
even	O
though	O
the	O
cost	O
to	O
produce	O
the	O
media	O
was	O
reduced	O
.	O
</s>
<s>
This	O
continued	O
from	O
phonograph	O
records	O
to	O
CDs	B-Device
,	O
but	O
was	O
broken	O
when	O
Apple	O
marketed	O
MP3s	B-Application
for	O
$0.99	O
,	O
and	O
albums	O
for	O
$9.99	O
.	O
</s>
<s>
The	O
incremental	O
cost	O
,	O
though	O
,	O
to	O
produce	O
an	O
MP3	B-Application
is	O
negligible	O
.	O
</s>
<s>
Recordable	O
Compact	O
Discs	O
,	O
CD-Rs	O
,	O
are	O
injection-molded	O
with	O
a	O
"	O
blank	O
"	O
data	O
spiral	O
.	O
</s>
<s>
The	O
write	O
laser	O
of	O
the	O
CD	B-Device
recorder	O
changes	O
the	O
color	O
of	O
the	O
dye	O
to	O
allow	O
the	O
read	O
laser	O
of	O
a	O
standard	O
CD	B-Device
player	I-Device
to	O
see	O
the	O
data	O
,	O
just	O
as	O
it	O
would	O
with	O
a	O
standard	O
stamped	O
disc	O
.	O
</s>
<s>
The	O
resulting	O
discs	O
can	O
be	O
read	O
by	O
most	O
CD-ROM	B-Device
drives	O
and	O
played	O
in	O
most	O
audio	O
CD	B-Device
players	I-Device
.	O
</s>
<s>
CD-Rs	O
follow	O
the	O
Orange	O
Book	O
standard	O
.	O
</s>
<s>
CD-R	O
recordings	O
are	O
designed	O
to	O
be	O
permanent	O
.	O
</s>
<s>
This	O
failure	O
is	O
known	O
as	O
disc	B-Device
rot	I-Device
,	O
for	O
which	O
there	O
are	O
several	O
,	O
mostly	O
environmental	O
,	O
reasons	O
.	O
</s>
<s>
The	O
recordable	O
audio	O
CD	B-Device
is	O
designed	O
to	O
be	O
used	O
in	O
a	O
consumer	O
audio	O
CD	B-Device
recorder	O
.	O
</s>
<s>
These	O
consumer	O
audio	O
CD	B-Device
recorders	O
use	O
SCMS	O
(	O
Serial	O
Copy	O
Management	O
System	O
)	O
,	O
an	O
early	O
form	O
of	O
digital	O
rights	O
management	O
(	O
DRM	O
)	O
,	O
to	O
conform	O
to	O
the	O
AHRA	O
(	O
Audio	O
Home	O
Recording	O
Act	O
)	O
.	O
</s>
<s>
The	O
Recordable	O
Audio	O
CD	B-Device
is	O
typically	O
somewhat	O
more	O
expensive	O
than	O
CD-R	O
due	O
to	O
lower	O
production	O
volume	O
and	O
a	O
3	O
percent	O
AHRA	O
royalty	O
used	O
to	O
compensate	O
the	O
music	O
industry	O
for	O
the	O
making	O
of	O
a	O
copy	O
.	O
</s>
<s>
High-capacity	O
recordable	O
CD	B-Device
is	O
a	O
higher-density	O
recording	O
format	O
that	O
can	O
hold	O
20%	O
more	O
data	O
than	O
conventional	O
discs	O
.	O
</s>
<s>
CD-RW	O
is	O
a	O
re-recordable	O
medium	O
that	O
uses	O
a	O
metallic	O
alloy	O
instead	O
of	O
a	O
dye	O
.	O
</s>
<s>
A	O
CD-RW	O
does	O
not	O
have	O
as	O
great	O
a	O
difference	O
in	O
reflectivity	O
as	O
a	O
pressed	O
CD	B-Device
or	O
a	O
CD-R	O
,	O
and	O
so	O
many	O
earlier	O
CD	B-Device
audio	O
players	O
cannot	O
read	O
CD-RW	O
discs	O
,	O
although	O
most	O
later	O
CD	B-Device
audio	O
players	O
and	O
stand-alone	O
DVD	O
players	O
can	O
.	O
</s>
<s>
CD-RWs	O
follow	O
the	O
Orange	O
Book	O
standard	O
.	O
</s>
<s>
The	O
ReWritable	O
Audio	O
CD	B-Device
is	O
designed	O
to	O
be	O
used	O
in	O
a	O
consumer	O
audio	O
CD	B-Device
recorder	O
,	O
which	O
will	O
not	O
(	O
without	O
modification	O
)	O
accept	O
standard	O
CD-RW	O
discs	O
.	O
</s>
<s>
These	O
consumer	O
audio	O
CD	B-Device
recorders	O
use	O
the	O
Serial	O
Copy	O
Management	O
System	O
(	O
SCMS	O
)	O
,	O
an	O
early	O
form	O
of	O
digital	O
rights	O
management	O
(	O
DRM	O
)	O
,	O
to	O
conform	O
to	O
the	O
United	O
States	O
 '	O
Audio	O
Home	O
Recording	O
Act	O
(	O
AHRA	O
)	O
.	O
</s>
<s>
The	O
ReWritable	O
Audio	O
CD	B-Device
is	O
typically	O
somewhat	O
more	O
expensive	O
than	O
CD-R	O
due	O
to	O
(	O
a	O
)	O
lower	O
volume	O
and	O
(	O
b	O
)	O
a	O
3	O
percent	O
AHRA	O
royalty	O
used	O
to	O
compensate	O
the	O
music	O
industry	O
for	O
the	O
making	O
of	O
a	O
copy	O
.	O
</s>
<s>
The	O
Red	O
Book	O
audio	O
specification	O
,	O
except	O
for	O
a	O
simple	O
"	O
anti-copy	O
"	O
statement	O
in	O
the	O
subcode	O
,	O
does	O
not	O
include	O
any	O
copy	B-Application
protection	I-Application
mechanism	O
.	O
</s>
<s>
Known	O
at	O
least	O
as	O
early	O
as	O
2001	O
,	O
attempts	O
were	O
made	O
by	O
record	O
companies	O
to	O
market	O
"	O
copy-protected	O
"	O
non-standard	O
compact	O
discs	O
,	O
which	O
cannot	O
be	O
ripped	O
,	O
or	O
copied	O
,	O
to	O
hard	B-Device
drives	I-Device
or	O
easily	O
converted	O
to	O
other	O
formats	O
(	O
like	O
FLAC	B-Application
,	O
MP3	B-Application
or	O
Vorbis	B-Algorithm
)	O
.	O
</s>
<s>
One	O
major	O
drawback	O
to	O
these	O
copy-protected	O
discs	O
is	O
that	O
most	O
will	O
not	O
play	O
on	O
either	O
computer	O
CD-ROM	B-Device
drives	O
or	O
some	O
standalone	O
CD	B-Device
players	I-Device
that	O
use	O
CD-ROM	B-Device
mechanisms	O
.	O
</s>
<s>
Numerous	O
copy-protection	B-Application
systems	O
have	O
been	O
countered	O
by	O
readily	O
available	O
,	O
often	O
free	O
,	O
software	O
,	O
or	O
even	O
by	O
simply	O
turning	O
off	O
automatic	O
AutoPlay	O
to	O
prevent	O
the	O
running	O
of	O
the	O
DRM	O
executable	B-Application
program	I-Application
.	O
</s>
