Description


Holographic Versatile Disc (HVD) is a high-capacity optical disc from the HVD Alliance that combines single beam holographic storage and DVD technologies to provide storage capacities starting at 500GB. Still in the testing phases, this new optical disc technology can hold up to 3.9 terabytes of information. This is equivalent to 4,600-11,900 hours of video. HVDs are able to store more data than current disks partly because of the holograms being stored in overlapping patterns. A traditional disk stores information side-by-side in a thin layer. This detracts from the amount of space available to use on the disk. The HVD disks have a thicker recording layer and use almost the entire volume of the disk to store information. Unlike other formats, the laser moves and the disc does not spin. It is also capable of parallel lines. The HVD Alliance was formed in early 2005 and expects to release the first HVDs in late 2007.


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Holography


HVD is based on the technology of Holography, a method of recording patterns of light to produce a three-dimensional object. A hologram is created by splitting a laser beam into two separate beams; a reference beam and an information beam. The information beam encounters images and carries them in its waveforms. The two beams then interesect to create a pattern of light interference. This light interference pattern can be recorded on a photosensitive polymer layer of a disc. To retrieve the information, the reference beam is then shined onto the hologram and reflected back into the light pattern of the image. The beam is then sent to the CMOS sensor to reproduce the original image.

How HVD Works


Writing Data


A simplified HVD system consists of the following main components:

  • Blue or green laser (532-nm wavelength in the test system)
  • Beam splitter/merger
  • Mirrors
  • Spatial light modulator (SLM)
  • CMOS sensor
  • Photopolymer recording medium

The information that needs to be written onto the disk is encoded into binary data and stored in the SLM. This page is the image that the information beam will pass through. Now that the page is created, a beam is fired into the beam splitter, creating the reference beam, which is directed away from the SLM and the information beam and is then directed through the SLM. The holography data is formed when the two beams rejoin on the same axis and this joint beam carries the data to the photopolymer disc and stores it there as a hologram.

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Reading Data


The light pattern that is now stored on the HVD disk needs to be read if the data is to be retrieved. The reader uses a laser to project a light beam onto the hologram. This light beam is identical to the reference beam that was used to write the data there. The hologram diffracts this beam according to the light interference it is storing. The light is a recreation of the original image of the page data. This beam of light is called the reconstruction beam. Once the reconstruction beam is bounced off of the disc, it is directed to the CMOS sensor. This sensor then reproduces the page data.

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HVD Alliance


HVD Alliance is a consortium of leading producers, market-makers and customers focused on developing and promoting Holographic Information Storage systems and standardizing products based on those technologies. It is an independent and vendor-neutral voluntary organization. HVD Alliance is governed by an Executive Committee.

HVD Alliance aims to:

      • Provide a forum for communication and periodic gatherings of members
      • Develop and execute on a Strategic Roadmap for undertaking Holographic HVD media interchange standardization
      • Design and undertake Round-Robin HVD media interchange testing
      • HVD Media Interchange Standards Compliance Testing and Certification by media-independent and vendor-neutral laboratories
      • HVD Recorder/Reproducer (Drive) Certification
      • Test and promote interoperability between HVD Certified Media and HVD Certified Recorders/Reproducers, Autochangers and related hardware
      • Perform HVD Alliance Demonstrations
      • Document best practices
      • Resolve early issues with developers and users to enable rapid adoption of technology advances


HD Format Comparison


Blu-ray
HD-DVD
HVD
Initial cost for recordable disc
Approx. $18
Approx. $10
Approx. $120
Initial cost for recorder/player
Approx. $2,000
Approx. $2,000
Approx. $3,000
Initial storage capacity
54 GB
30 GB
300 GB
Read/write speed
36.5 Mbps
36.5 Mbps
1 Gbps

Advantages of HVD


Naturally, it can store a tremendous amount more than current competitors. It reads and writes incredibly quickly and for the price you are getting what you pay for. Fortunately, the price of HVD, as well as all other formats, will drop dramatically through the coming years.

Disadvantages of HVD


The initial price of the player and discs themselves are far more expensive than HD-DVD or Blu-ray. It could be argued that the public is not entirely ready for even the costs or benefits of Blu-ray or HD-DVD, much less HVD. None of the prices or storage capacities are completely confirmed as HVD is still under heavy R&D.

Application


HVD will of course be used for storing large amounts of data most likely for large companies. Due to the shear amount it can store, it could be the most efficient way to backup information in the near future. In the future it could be possible to be used as a new movie format or possibly for software.



Related
HD DVD
Blu-ray Disc
Holographic memory



Web Resources

http://www.hvd-alliance.org
http://www.hvd.cn/en/index.htm
http://electronics.howstuffworks.com/hvd.htm
http://www.engadget.com/2004/08/24/optwares-1tb-holographic-versatile-disc/