Holographic Versatile Discs
) have the capacity to hold up to 1 terabytes (TB) of information, which is approximately 33x
times the capacity of HD-DVD Disks and 20x
the capacity of Blu-ray Discs. The HVD also has a transfer rate of 1 Gbit/s.
HVD recording technology records data on discs in the form of laser
interference fringes, enabling existing discs the same size as today's
DVDs to store as much as one terabyte of data, with a transfer speed of
one gigabyte per second (40 times the speed of DVD). This approach is
rapidly gaining attention as "a high-capacity, high-speed data storage
technology for the age of broadband".
It employs a technique known as collinear holography, whereby two
lasers, one red and one blue-green, are collimated in a single beam.
The blue-green laser reads data encoded as laser interference fringes
from a holographic layer near the top of the disc while the red laser
is used to read servo information from a regular CD-style aluminium
layer near the bottom. Servo information is used to monitor the
position of the read head over the disc, similar to the head, track,
and sector information on a conventional hard disk drive. On a CD or
DVD this servo information is interspersed amongst the data. A dichroic
mirror layer between the holographic data and the servo data reflects
the blue-green laser while letting the red laser pass through. This
prevents interference from refraction of the blue-green laser off the
servo data pits and is an advance over past holographic storage media,
which either experienced too much interference, or lacked the servo
data entirely, making them incompatible with current CD and DVD drive
Not only that, but HVD seems to be gathering a small following including such companies as:
- CMC Magnetics Corporation
- Fuji Photo Film Co., Ltd.
- Konica Minolta Optical, Inc.
- Mitsubishi Kagaku Media Co., Ltd.
- EMTEC (MPO International)
- Nippon Paint Co., Ltd.
- Optware Corporation
- Pulstec Industrial Co., Ltd.
- Software Architects, Inc.
- Toagosei Co., Ltd.
What does everyone think?
Should we really be looking at HD-DVD, and Blu-Ray as the next generation of data storage?