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Holographic Versatile Disc

 
 

(1) (High Voltage Differential) See SCSI and differential signaling.

(2) (Holographic Versatile Disc) A high-capacity optical disc from the HVD Forum (www.hvd-forum.org) that combines single beam holographic storage and DVD technologies to provide cartridge capacities reaching 1TB and beyond. Formed in 2005 as the HVD Alliance, the first HVD standards were released in 2007 for 100GB read-only (ECMA-378) and 200GB recordable (ECMA-377) formats.

HVD uses the conventional CD/DVD pit layer for addressing the disc, on top of which is the holographic recording layer. A red laser reads the addresses, while a green or blue laser reads and writes the holograms.

Single Beam Holography

Throughout the history of holographic storage research, two separate laser beams have been used to write the holograms at the intersecting point. Using Optware's Collinear Holography, HVD combines the two lasers into one lens, which reduces the size and cost of the mechanism. See holographic storage.

Layers in an HVD Disc

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Abbreviations: HVD
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is short for:

Meaning Category
High Voltage DifferentialAcademic & Science->Electronics
Holographic Versatile DiscComputing->General
Hypertensive Vascular DiseaseMedical->Physiology
Khovd, MongoliaRegional->Airport Codes

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Wikipedia: Holographic Versatile Disc
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Holographic Versatile Disc
Image:HVD logo.png

Picture of an HVD by Optware
Media type Ultra-high density optical disc
Encoding MPEG-2, MPEG-4 AVC (H.264), and VC-1
Capacity Theoretically up to 1 or 6TB possibility of 10TB to 100 TB
Developed by HSD Forum
Usage Data storage,
High-definition video,[Quad HD & the possibility of ultra high definition video

The Holographic Versatile Disc (HVD) is an optical disc technology that, in the future, may hold up to 6TB (terabytes) of information, although the current maximum is 500GB. It employs a technique known as collinear holography, whereby two lasers, one Blue 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 Blue laser is used as the reference beam and to read servoinformation from a regular CD-style aluminum layer near the bottom. Servoinformation 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 servoinformation is interspersed amongst the data.

A dichroic mirror layer between the holographic data and the servo data reflects the green laser while letting the Blue 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 6 terabytes (TB) of information. The HVD also has a transfer rate of 1 Gbit/s (300 MB/s). Sony Philips, TDK, Panasonic, Optware, and planned to release a 1 TB discs in late 2016, and Maxell planned one for early 2017 with a capacity of 500 GB and transfer rate of 20 MB/s[2]—although HVD standards were approved and published on June 28, 2007, no company has released a HVD as of JULY, 2009.[3]

Contents

Technology

Optical disc authoring
Optical media types
Standards
Further reading
Holographic Versatile Disc structure
1. Green writing/reading laser (300 nm)
2. Blue positioning/addressing laser (350 nm)
3. Hologram (data)
4. Polycarbonate layer
5. Photopolymeric layer (data-containing layer)
6. Distance layers
7. Dichroic layer (reflecting green light)
8. Aluminum reflective layer (reflecting red light)
9. Transparent base
P. PIT

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 5 TB for 3 micrometer separation on a 10 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]

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 the Blu-ray Disc format. 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.

Holography System Development Forum

The Holography System Development Forum (HSD Forum; formerly the HVD Alliance and the HVD FORUM) is a coalition of corporations purposed to provide an industry forum for testing and technical discussion of all aspects of HVD design and manufacturing.

As of JULY/AUGUST 2009, the HVD Forum comprised these corporations:

Some members of the Blu-ray Disc Association and HD DVD Promotion Group are also involved

Standards

On December 9, 2004 at its 88th General Assembly the standards body Ecma International created Technical Committee 44, dedicated to standardizing 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]

[9] New High Definition Video Technologies Road Map (2004-2010) From Maxell Corporation of America

References

News

27 April 2009: GE unveils a 500GB disc. BBC News

See also

External links


 
 

 

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