Holographic Versatile Disc (1 Viewer)

[SashatheMan]

Holographic Versatile Disc (HVD) is an advanced optical disc technology still in the research stage which would greatly increase storage over Blu-ray and HD DVD optical disc systems. 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 technology [1]. These disks have the capacity to hold up to 3.9 terabytes (TB) of information, which is approximately 160 times the capacity of single-layer Blu-ray Discs. The HVD also has a transfer rate of 1 Gbit/s. Optware is expected to release a 200GB disc in early june of 2006.

ContextThe books in the U.S. Library of Congress, one of the largest libraries in the world, contain a total of about 20 terabytes of text. Neglecting images, the content could be stored on a little more than 6 of these discs.

The article notes that the transfer rate is at an average of 1 gigabit/second. That is equal to 128 megabytes/second, which is a large leap over earlier storage media. In comparison, a 56x CD-ROM drive transfers at up to 8.4 Megabytes/second, 16x-speed DVDs transfer at 22 Megabytes/second and the fastest 15k rpm hard drives transfer at ~100 Megabytes/second.

At this rate it would take only 4.7 seconds to transfer an entire heavily compressed movie (600 MB) and about 8hours and 40 minutes to transfer over 820 DVD movies (roughly the storage capacity of the 3.9TB disk).

Gigabit bandwidth is approximately double the data bandwidth necessary to transfer uncompressed 1280x720 24-bit color video at 24 frames per second, with six channel uncompressed 192k 24-bit PCM audio. At one terabyte, an HVD would be able to store approximately 4 hours of this type of content.

http://en.wikipedia.org/wiki/Holographic_Versatile_Disc




i must say wow. this is Phat

 

[MedNez]

Interesting- it looks as if the brewing war between Blu-ray and HD DVD discs is about to get a third competitor!

 

[SashatheMan]

Interesting- it looks as if the brewing war between Blu-ray and HD DVD discs is about to get a third competitor!

actually i didnt include one part from the wiki link. But it sais theres also a competing brand that uses this holographic technology , so theres gonna be two more competitors.