<s>
The	O
Holographic	B-Device
Versatile	I-Device
Disc	I-Device
(	O
HVD	O
)	O
is	O
an	O
optical	B-Device
disc	I-Device
technology	O
that	O
was	O
expected	O
to	O
store	O
up	O
to	O
several	O
terabytes	O
of	O
data	O
on	O
an	O
optical	B-Device
disc	I-Device
10cm	O
or	O
12cm	O
in	O
diameter	O
.	O
</s>
<s>
It	O
employs	O
a	O
technique	O
known	O
as	O
collinear	O
holography	B-Algorithm
,	O
whereby	O
a	O
blue-green	O
and	O
red	O
laser	O
beam	O
are	O
collimated	O
in	O
a	O
single	O
beam	O
.	O
</s>
<s>
The	O
blue-green	O
laser	O
reads	O
data	O
encoded	O
as	O
laser	O
interference	O
fringes	O
from	O
a	O
holographic	B-Algorithm
layer	O
near	O
the	O
top	O
of	O
the	O
disc	O
.	O
</s>
<s>
Servoinformation	O
is	O
used	O
to	O
monitor	O
the	O
position	O
of	O
the	O
read	O
head	O
over	O
the	O
disc	O
,	O
similar	O
to	O
the	O
head	O
,	O
track	O
,	O
and	O
sector	O
information	O
on	O
a	O
conventional	O
hard	B-Device
disk	I-Device
drive	I-Device
.	O
</s>
<s>
A	O
dichroic	O
mirror	O
layer	O
between	O
the	O
holographic	B-Algorithm
data	O
and	O
the	O
servo	O
data	O
reflects	O
the	O
blue-green	O
laser	O
while	O
letting	O
the	O
red	O
laser	O
pass	O
through	O
.	O
</s>
<s>
This	O
prevents	O
interference	O
from	O
refraction	O
of	O
the	O
blue-green	O
laser	O
off	O
the	O
servo	O
data	O
pits	O
and	O
is	O
an	O
advance	O
over	O
past	O
holographic	B-Algorithm
storage	I-Algorithm
media	O
,	O
which	O
either	O
experienced	O
too	O
much	O
interference	O
,	O
or	O
lacked	O
the	O
servo	O
data	O
entirely	O
,	O
making	O
them	O
incompatible	O
with	O
current	O
CD	O
and	O
DVD	O
drive	O
technology	O
.	O
</s>
<s>
Standards	O
for	O
100GB	O
read-only	O
holographic	B-Device
discs	I-Device
and	O
200GB	O
recordable	O
cartridges	O
were	O
published	O
by	O
ECMA	O
in	O
2007	O
,	O
but	O
no	O
holographic	B-Device
disc	I-Device
product	O
has	O
ever	O
appeared	O
in	O
the	O
market	O
.	O
</s>
<s>
A	O
number	O
of	O
release	O
dates	O
were	O
announced	O
,	O
all	O
since	O
passed	O
,	O
likely	O
due	O
to	O
high	O
costs	O
of	O
the	O
drives	O
and	O
discs	O
itself	O
,	O
lack	O
of	O
compatibility	O
with	O
existing	O
or	O
new	O
standards	O
,	O
and	O
competition	O
from	O
video	B-Application
streaming	I-Application
.	O
</s>
<s>
Possible	O
solutions	O
include	O
improving	O
the	O
sensitivity	O
of	O
the	O
polymer	B-Language
used	O
,	O
or	O
developing	O
and	O
commoditizing	O
a	O
laser	O
capable	O
of	O
higher	O
power	O
output	O
while	O
being	O
suitable	O
for	O
a	O
consumer	O
unit	O
.	O
</s>
<s>
HVD	O
is	O
not	O
the	O
only	O
technology	O
in	O
high-capacity	O
,	O
holographic	B-Algorithm
storage	I-Algorithm
media	O
.	O
</s>
<s>
InPhase	B-Algorithm
Technologies	I-Algorithm
was	O
developing	O
a	O
rival	O
holographic	B-Algorithm
format	O
called	O
Tapestry	O
Media	O
,	O
which	O
they	O
claimed	O
would	O
eventually	O
store	O
1.6TB	O
with	O
a	O
data	O
transfer	O
rate	O
of	O
120	O
MB/s	O
,	O
and	O
several	O
companies	O
are	O
developing	O
TB-level	O
discs	O
based	O
on	O
3D	O
optical	O
data	O
storage	O
technology	O
.	O
</s>
<s>
However	O
,	O
in	O
2006	O
,	O
holographic	B-Algorithm
drives	O
were	O
projected	O
to	O
initially	O
cost	O
around	O
US$15	O
,	O
000	O
,	O
and	O
a	O
single	O
disc	O
around	O
US$120	O
–	O
180	O
,	O
although	O
prices	O
were	O
expected	O
to	O
fall	O
steadily	O
.	O
</s>
<s>
Since	O
InPhase	B-Algorithm
Technologies	I-Algorithm
was	O
unable	O
to	O
deliver	O
their	O
promised	O
product	O
,	O
they	O
ran	O
out	O
of	O
funds	O
and	O
went	O
bankrupt	O
in	O
2010	O
.	O
</s>
<s>
The	O
Holography	B-Algorithm
System	O
Development	O
Forum	O
(	O
HSD	O
Forum	O
;	O
formerly	O
the	O
HVD	O
Alliance	O
and	O
the	O
HVD	O
FORUM	O
)	O
is	O
a	O
coalition	O
of	O
corporations	O
purposed	O
to	O
provide	O
an	O
industry	O
forum	O
for	O
testing	O
and	O
technical	O
discussion	O
of	O
all	O
aspects	O
of	O
HVD	O
design	O
and	O
manufacturing	O
.	O
</s>
<s>
On	O
June	O
11	O
,	O
2007	O
,	O
TC44	O
published	O
the	O
first	O
two	O
HVD	O
standards	O
:	O
ECMA-377	B-Device
,	O
defining	O
a	O
200GB	O
HVD	O
"	O
recordable	O
cartridge	O
"	O
and	O
ECMA-378	B-Device
,	O
defining	O
a	O
100GB	O
HVD-ROM	O
disc	O
.	O
</s>
<s>
General	O
Electric	O
Global	O
Research	O
Centers	O
created	O
a	O
holographic	B-Device
disc	I-Device
that	O
could	O
hold	O
many	O
times	O
the	O
data	O
of	O
a	O
Blu-Ray	O
—	O
up	O
to	O
500GB	O
.	O
</s>
