<s>
Optical	B-Application
disc	I-Application
authoring	I-Application
requires	O
a	O
number	O
of	O
different	O
optical	B-Device
disc	I-Device
recorder	O
technologies	O
working	O
in	O
tandem	O
,	O
from	O
the	O
optical	B-Device
disc	I-Device
media	I-Device
to	O
the	O
firmware	B-Application
to	O
the	O
control	O
electronics	O
of	O
the	O
optical	B-Device
disc	I-Device
drive	O
.	O
</s>
<s>
There	O
are	O
numerous	O
formats	O
of	O
recordable	O
optical	O
direct	O
to	O
disk	O
on	O
the	O
market	O
,	O
all	O
of	O
which	O
are	O
based	O
on	O
using	O
a	O
laser	O
to	O
change	O
the	O
reflectivity	O
of	O
the	O
digital	O
recording	O
medium	O
in	O
order	O
to	O
duplicate	O
the	O
effects	O
of	O
the	O
pits	O
and	O
lands	O
created	O
when	O
a	O
commercial	O
optical	B-Device
disc	I-Device
is	O
pressed	O
.	O
</s>
<s>
Emerging	O
technologies	O
such	O
as	O
holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
and	O
3D	O
optical	O
data	O
storage	O
aim	O
to	O
use	O
entirely	O
different	O
data	O
storage	O
methods	O
,	O
but	O
these	O
products	O
are	O
in	O
development	O
and	O
are	O
not	O
yet	O
widely	O
available	O
.	O
</s>
<s>
The	O
earliest	O
form	O
is	O
magneto-optical	B-Device
,	O
which	O
uses	O
a	O
magnetic	O
field	O
in	O
combination	O
with	O
a	O
laser	O
to	O
write	O
to	O
the	O
medium	O
.	O
</s>
<s>
The	O
most	O
common	O
form	O
of	O
recordable	O
optical	B-Device
media	I-Device
is	O
write-once	B-Device
organic	O
dye	O
technology	O
,	O
popularized	O
in	O
the	O
form	O
of	O
the	O
CD-R	O
and	O
still	O
used	O
for	O
higher-capacity	O
media	O
such	O
as	O
DVD-R	O
.	O
</s>
<s>
Rewritable	O
,	O
non-magnetic	O
optical	B-Device
media	I-Device
are	O
possible	O
using	O
phase	O
change	O
alloys	O
,	O
which	O
are	O
converted	O
between	O
crystalline	O
and	O
amorphous	O
states	O
(	O
with	O
different	O
reflectivity	O
)	O
using	O
the	O
heat	O
from	O
the	O
drive	O
laser	O
.	O
</s>
<s>
Another	O
technology	O
creates	O
pits	O
in	O
an	O
inorganic	O
carbon	O
layer	O
,	O
a	O
"	O
write-once	B-Device
"	O
option	O
.	O
</s>
<s>
Created	O
by	O
Millenniata	B-Device
,	O
M-DISC	B-Device
,	O
records	O
data	O
on	O
special	O
M-DISC	B-Device
with	O
a	O
data	O
life-time	O
of	O
several	O
hundred	O
years	O
.	O
</s>
<s>
Optical	B-Device
discs	I-Device
can	O
be	O
recorded	O
in	O
Disc	B-Application
At	I-Application
Once	I-Application
,	O
Track	B-Application
At	I-Application
Once	I-Application
,	O
Session	O
at	O
Once	O
(	O
i.e.	O
</s>
<s>
multiple	O
burning	O
sessions	O
for	O
one	O
disc	O
)	O
,	O
or	O
packet	B-Device
writing	I-Device
modes	O
.	O
</s>
<s>
Unlike	O
early	O
CD-ROM	B-Device
drives	O
,	O
optical	B-Device
disc	I-Device
recorder	O
drives	O
have	O
generally	O
used	O
industry	O
standard	O
connection	O
protocols	O
.	O
</s>
<s>
Early	O
computer-based	O
CD	O
recorders	O
were	O
generally	O
connected	O
by	O
way	O
of	O
SCSI	B-Architecture
;	O
however	O
,	O
as	O
SCSI	B-Architecture
was	O
abandoned	O
by	O
its	O
most	O
significant	O
users	O
(	O
particularly	O
Apple	O
Computer	O
)	O
,	O
it	O
became	O
an	O
expensive	O
option	O
for	O
most	O
computer	O
users	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
the	O
market	O
switched	O
over	O
to	O
Parallel	B-Protocol
ATA	I-Protocol
connections	O
for	O
most	O
internal	O
drives	O
;	O
external	O
drives	O
generally	O
use	O
PATA	B-Protocol
drive	O
mechanisms	O
connected	O
to	O
a	O
bridge	O
inside	O
the	O
case	O
that	O
connects	O
to	O
a	O
high-speed	O
serial	O
bus	O
such	O
as	O
FireWire	B-Protocol
or	O
Hi-Speed	O
USB	B-Protocol
2.0	I-Protocol
.	O
</s>
<s>
Standalone	O
recorders	O
use	O
standard	O
A/V	O
connections	O
,	O
including	O
RCA	B-Protocol
connectors	I-Protocol
,	O
TOSlink	B-Protocol
,	O
and	O
S/PDIF	O
for	O
audio	O
and	O
RF	O
,	O
composite	O
video	O
,	O
component	O
video	O
,	O
S-Video	O
,	O
SCART	B-Protocol
,	O
and	O
FireWire	B-Protocol
for	O
video	O
.	O
</s>
<s>
High-bandwidth	O
digital	O
connections	O
such	O
as	O
HDMI	B-Protocol
are	O
unlikely	O
to	O
feature	O
as	O
recorder	O
devices	O
are	O
not	O
permitted	O
to	O
decrypt	O
the	O
encrypted	B-Protocol
video	O
content	O
.	O
</s>
<s>
Structures	O
in	O
the	O
ATIP	B-Device
do	O
not	O
allow	O
such	O
sizes	O
to	O
be	O
specified	O
.	O
</s>
<s>
A	O
buffer	B-General_Concept
underrun	O
occurs	O
during	O
recording	O
if	O
the	O
supply	O
of	O
data	O
to	O
the	O
recorder	O
is	O
interrupted	O
before	O
the	O
write	O
is	O
complete	O
.	O
</s>
<s>
Software	O
typically	O
moves	O
the	O
data	O
to	O
be	O
recorded	O
into	O
a	O
buffer	B-General_Concept
;	O
underrun	O
occurs	O
if	O
the	O
recorder	O
processes	O
data	O
in	O
the	O
buffer	B-General_Concept
faster	O
than	O
the	O
software	O
reloads	O
it	O
.	O
</s>
<s>
Historically	O
,	O
buffer	B-General_Concept
underrun	O
was	O
often	O
caused	O
by	O
writing	O
data	O
obtained	O
from	O
a	O
slow	O
device	O
,	O
or	O
by	O
slowness	O
of	O
the	O
recording	O
software	O
,	O
from	O
a	O
slow	O
processor	O
or	O
a	O
processor	O
executing	O
other	O
tasks	O
concurrently	O
.	O
</s>
<s>
Various	O
recorders	O
minimize	O
or	O
cope	O
with	O
buffer	B-General_Concept
underrun	O
in	O
the	O
following	O
ways	O
:	O
</s>
<s>
A	O
burner	O
may	O
do	O
so	O
on	O
sensing	O
that	O
it	O
is	O
drawing	O
down	O
the	O
data	O
in	O
the	O
buffer	B-General_Concept
faster	O
than	O
software	O
is	O
reloading	O
it	O
.	O
</s>
<s>
Recording	O
software	O
maintains	O
larger	O
buffers	B-General_Concept
than	O
when	O
CD	O
recorders	O
were	O
first	O
introduced	O
.	O
</s>
<s>
Some	O
recorders	O
maintain	O
their	O
own	O
buffer	B-General_Concept
memory	O
independently	O
of	O
the	O
computer	O
.	O
</s>
<s>
This	O
additional	O
buffering	O
ensures	O
that	O
momentary	O
pauses	O
in	O
the	O
supply	O
of	O
data	O
do	O
not	O
cause	O
buffer	B-General_Concept
underrun	O
.	O
</s>
<s>
Some	O
recorders	O
are	O
,	O
in	O
fact	O
,	O
able	O
to	O
stop	O
writing	O
in	O
the	O
middle	O
of	O
a	O
session	O
,	O
and	O
resume	O
writing	O
whenever	O
the	O
buffer	B-General_Concept
is	O
refilled	O
.	O
</s>
<s>
Recorders	O
with	O
such	O
buffer	B-General_Concept
underrun	O
protection	O
handle	O
the	O
interruption	O
with	O
an	O
extremely	O
small	O
gap	O
in	O
the	O
recorded	O
track	O
on	O
the	O
disc	O
.	O
</s>
<s>
Since	O
the	O
techniques	O
for	O
protecting	O
against	O
buffer	B-General_Concept
underrun	O
are	O
proprietary	O
and	O
vendor-specific	O
,	O
technical	O
details	O
vary	O
.	O
</s>
<s>
DVD+R	O
,	O
DVD+RW	O
and	O
the	O
recordable	O
Blu-ray	O
formats	O
are	O
immune	O
from	O
buffer	B-General_Concept
underrun	O
as	O
these	O
discs	O
contain	O
technology	O
that	O
allows	O
the	O
recorder	O
's	O
write	O
mechanism	O
to	O
precisely	O
locate	O
the	O
end	O
of	O
the	O
recorded	O
track	O
and	O
to	O
seamlessly	O
carry	O
on	O
from	O
where	O
it	O
left	O
off	O
.	O
</s>
<s>
Many	O
disc	O
authoring	O
utilities	O
disable	O
the	O
buffer	B-General_Concept
underrun	O
protection	O
option	O
when	O
these	O
discs	O
are	O
being	O
written	O
.	O
</s>
<s>
Buffer	B-General_Concept
underrun	O
is	O
minimized	O
by	O
a	O
strategy	O
in	O
which	O
the	O
recorder	O
burns	O
a	O
packet	B-Device
rather	O
than	O
an	O
entire	O
session	O
or	O
an	O
entire	O
disc	O
.	O
</s>
<s>
BURN-Proof	B-Device
(	O
Buffer	B-General_Concept
Underrun-Proof	O
)	O
is	O
a	O
proprietary	O
technology	O
for	O
buffer	B-General_Concept
underrun	O
protection	O
developed	O
by	O
Sanyo	O
.	O
</s>
<s>
FlextraLink	O
is	O
a	O
proprietary	O
technology	O
for	O
buffer	B-General_Concept
underrun	O
protection	O
developed	O
by	O
Asus	O
.	O
</s>
<s>
Power	B-Device
Burn	I-Device
is	O
a	O
proprietary	O
technology	O
for	O
buffer	B-General_Concept
underrun	O
protection	O
,	O
developed	O
by	O
Sony	O
.	O
</s>
<s>
Buffer	B-General_Concept
underrun	O
protection	O
:	O
When	O
a	O
buffer	B-General_Concept
underrun	O
occurs	O
,	O
the	O
drive	O
suspends	O
writing	O
.	O
</s>
<s>
The	O
drive	O
memorizes	O
the	O
end	O
writing	O
point	O
and	O
timing	O
,	O
and	O
immediately	O
resumes	O
writing	O
from	O
that	O
exact	O
point	O
when	O
sufficient	O
data	O
is	O
filled	O
in	O
the	O
buffer	B-General_Concept
memory	O
.	O
</s>
<s>
Protection	O
from	O
write	O
errors	O
caused	O
by	O
shock	O
and	O
vibration	O
:	O
PowerBurn	B-Device
's	O
Shock	O
Proof	O
technology	O
pauses	O
writing	O
when	O
the	O
device	O
is	O
moved	O
,	O
and	O
resumes	O
after	O
the	O
drive	O
becomes	O
stable	O
.	O
</s>
<s>
Optimization	O
of	O
write	O
conditions	O
:	O
The	O
drive	O
detects	O
characteristics	O
of	O
each	O
individual	O
medium	O
and	O
optimizes	O
all	O
key	O
writing	O
conditions	O
such	O
as	O
writing	O
speed	O
,	O
laser	O
power	O
and	O
write	B-Application
strategy	I-Application
.	O
</s>
<s>
SafeBurn	B-Device
is	O
a	O
proprietary	O
technology	O
for	O
buffer	B-General_Concept
underrun	O
protection	O
developed	O
by	O
Yamaha	O
Corporation	O
.	O
</s>
<s>
Packet	B-Device
writing	I-Device
is	O
a	O
technology	O
that	O
allows	O
optical	B-Device
discs	I-Device
to	O
be	O
used	O
in	O
a	O
similar	O
manner	O
to	O
a	O
floppy	B-Device
disk	I-Device
.	O
</s>
<s>
Packet	B-Device
writing	I-Device
can	O
be	O
used	O
both	O
with	O
once-writeable	O
media	O
and	O
rewriteable	O
media	O
.	O
</s>
<s>
Several	O
competing	O
and	O
incompatible	O
packet	B-Device
writing	I-Device
disk	O
formats	O
have	O
been	O
developed	O
,	O
including	O
DirectCD	O
and	O
InCD	B-Application
.	O
</s>
<s>
The	O
standardized	O
formats	O
for	O
packet	B-Device
writing	I-Device
are	O
the	O
Universal	O
Disk	O
Format	O
in	O
the	O
plain	O
,	O
VAT	O
,	O
and	O
spared	O
builds	O
.	O
</s>
<s>
Using	O
the	O
simulated	O
writing	O
or	O
simulated	O
burning	O
feature	O
of	O
optical	B-Application
disc	I-Application
authoring	I-Application
software	O
,	O
the	O
writing	O
process	O
will	O
be	O
simulated	O
,	O
which	O
means	O
that	O
the	O
disc	O
spins	O
and	O
the	O
laser	O
moves	O
as	O
if	O
on	O
an	O
actual	O
writing	O
process	O
,	O
but	O
without	O
any	O
data	O
being	O
recorded	O
to	O
the	O
disc	O
.	O
</s>
<s>
constant	B-Device
angular	I-Device
velocity	I-Device
,	O
constant	B-Device
linear	I-Device
velocity	I-Device
and	O
P-CAV	O
and	O
Z-CLV	O
variants	O
)	O
with	O
different	O
writing	O
speed	O
settings	O
and	O
testing	O
the	O
highest	O
capacity	O
of	O
an	O
individual	O
disc	O
that	O
would	O
be	O
achievable	O
using	O
overburning	O
.	O
</s>
<s>
Retail	O
recordable/writable	O
optical	B-Device
media	I-Device
contain	O
dyes	O
in/on	O
the	O
optical	B-Device
media	I-Device
to	O
record	O
data	O
,	O
whereas	O
factory-manufactured	O
optical	B-Device
media	I-Device
use	O
physical	O
"	O
pits	O
"	O
created	O
by	O
plastic	O
molds/casts	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
data	O
storage	O
on	O
retail	O
optical	B-Device
media	I-Device
does	O
not	O
have	O
the	O
life-span	O
of	O
factory-manufactured	O
optical	B-Device
media	I-Device
.	O
</s>
<s>
Dye	O
based	O
optical	B-Device
media	I-Device
should	O
not	O
be	O
solely	O
relied	O
on	O
to	O
archive	O
valuable	O
data	O
.	O
</s>
<s>
Good	O
alternatives	O
would	O
be	O
to	O
additionally	O
backup	O
one	O
's	O
media	O
using	O
other	O
media	O
technologies	O
and/or	O
investing	O
in	O
non-volatile	B-General_Concept
memory	I-General_Concept
technologies	O
.	O
</s>
