Holographic Versatile Disc

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Holographic Versatile Disc (HVD) is an optical disc technology which would hold up to 3.9 terabytes (TB) of information. It employs a technique known as collinear holography, whereby two lasers, one red and one green, are collimated in a single beam. The 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 as the reference beam and 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 green laser while letting the red laser pass through. This prevents interference from refraction of the 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 technology.^[1] These discs have the capacity to hold up to 3.9 terabytes (TB) of information, which is approximately 5,500 times the capacity of a CD-ROM, 830 times the capacity of a DVD, 160 times the capacity of single-layer Blu-ray Discs, and about 4 times the capacity of the largest computer hard drives as of 2007. The HVD also has a transfer rate of 1 Gbit/s (128 MB/s). Optware was expected to release a 200 GB disc in early June 2006, and Maxell in September 2006 with a capacity of 300 GB and transfer rate of 20 MB/s.^[2] Since the announcement, there have been no further news or products on market.

[edit] Technology

Current optical storage saves one bit per pulse, and the HVD alliance hopes to improve this efficiency with capabilities of around 60,000 bits per pulse in an inverted, truncated cone shape that has a 200 micrometer diameter at the bottom and a 500 micrometer diameter at the top. High densities are possible by moving these closer on the tracks: 100 GB at 18 micrometers separation, 200 GB at 13 micrometers, 500 GB at 8 micrometers and a demonstrated maximum of 3.9 TB for 3 micrometer separation on a 12 cm disc.

The system uses a green laser, with an output power of 1 watt, a high power for a consumer device laser. So a major challenge of the project for widespread consumer markets is to either improve the sensitivity of the polymer used, or develop and commoditize a laser capable of higher power output and suitable for a consumer unit.^{[citation needed]}

[edit] Storage capacity in context

• It has been estimated that the books in the U.S. Library of Congress, one of the largest libraries in the world, would contain a total of about 20 terabytes if scanned in text format. Not including images from the books, the content could be stored with capacity to spare on six 3.9 TB discs.
• At 15 meter resolution and 32-bit color (about the resolution found in unpopulated areas on Google Earth), a map of the land masses of Earth would occupy just over 2 TB.
• Using MPEG4 ASP encoding, a 3.9 TB HVD could hold 4,600–11,900 hours of video—just over one year of uninterrupted video at usual encoding rates.^[3]
• Using typical satellite radio encoding (CT-aacPlus at 40 kbit/s), a 3.9 TB HVD could hold over 26.5 years of uninterrupted stereo audio.

[edit] Competing technologies

HVD is not the only technology in high-capacity, optical storage media. InPhase Technologies is developing a rival holographic format called Tapestry Media, which they claim will eventually store 1.6 TB with a data transfer rate of 120 MB/s, and several companies are developing TB-level discs based on 3D optical data storage technology. Such large optical storage capacities compete favorably with both HD DVD and Blu-ray Disc. However, holographic drives are projected to initially cost around US$15,000, and a single disc around US$120–180, although prices are expected to fall steadily.^[4] The market for this format is not initially the common consumer, but enterprises with very large storage needs.

[edit] The HVD FORUM

The HVD FORUM (formerly the HVD Alliance) is a coalition of corporations purposed to provide an industry forum for testing and technical discussion of all aspects of HVD design and manufacturing. By cooperating, members of the Forum hope to expedite development and engender a market receptive to HVD technology.

As of February 2006, the HVD FORUM comprises these corporations:

• Alps Electric Corporation, Ltd.
• CMC Magnetics Corporation
• Dainippon Ink and Chemicals, Inc. (DIC)
• EMTEC International (subsidiary of the MPO Group)
• Fuji Photo Film Company, Ltd.
• Konica Minolta Holdings, Inc.
• LiteOn Technology Corporation
• Mitsubishi Kagaku Media Company, Ltd. (MKM)
• Nippon Kayaku Co., Ltd.
• Nippon Paint Company, Ltd.
• Optware Corporation
• Pulstec Industrial Company, Ltd.
• Shibaura Mechatronics Corporation
• Software Architects, Inc. (?)
• Suruga Seiki Company, Ltd.
• Targray Technology International, Inc.
• Teijin Chemicals, Ltd.
• Toagosei Company, Ltd.
• Tokiwa Optical Corporation

[edit] Standards

On December 9, 2004 at its 88th General Assembly the standards body Ecma International created Technical Committee 44, dedicated to standarizing HVD formats based on Optware's technology. On June 11, 2007, TC44 published the first two HVD standards^[5]: ECMA-377^[6], defining a 200 GB HVD "recordable cartridge" and ECMA-378^[7], defining a 100 GB HVD-ROM disc. Its next stated goals are 30 GB HVD cards and submission of these standards to the International Organization for Standardization for ISO approval.^[8]

[edit] References

[edit] See also

• DVD
• Blu-ray Disc (BD)
• HD DVD (HDDVD)
• Ultra Density Optical (UDO)
• Professional Disc for DATA (PDD or ProDATA)
• Holographic memory
• Tapestry Media
• 3D optical data storage
• Protein-coated disc
• Magneto-optical drive (MO)
• Holographic Versatile Card
• Stacked Volumetric Optical Disk (SVOD)
• InPhase Technologies – developer of competing holographic disc

[edit] External links

• DaTARIUS signs agreement with InPhase Technologies to be their sole sales, service and support supplier of Tapestry Media hardware and media to ship starting in 2007 (300 GB WORM discs) with 600 GB discs and re-writable technology in 2008 as well as 1.6 TB media available in 2010.
• HVD Forum standards consortium.
• Optware, creator of HVD format.
• InPhase, a company developing a competing holographic storage format (*See Above).
• Video explaining holographic storage – PC Magazine, October 4, 2006
• Holography system rides single beam EE Times, 27 February 2006 – interview with Hideyoshi Horimai and Yoshio Aoki of Optware Corp.
• Holographic storage standards eyed EE Times, 28 February 2006 – article about the upcoming technical committee meeting to begin standardization of HVD.
• How stuff works explains how HVD works.

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