Fatal flaw in Optware HVD?
p2pnet.net News:- "Forget HD DVD, forget Blu-ray Disc, the future is the HVD – the Holographic Versatile Disc," says a recent story in DVD-Recordable.
It was attributing the claim to six Japanese companies who, led by Optware, plan to promote HVD technology which they say can put a terabyte (1TB) of data onto a single optical disc.
However, US data storage pioneer Michael Thomas, who’s staked out holographic storage for his own, wasn’t impressed when the announcement was made, and he’s even less impressed now.
The Optware design has potentially fatal flaws in the media allowing data/servo head information to increase read data error rates, he states.
In 1974, Thomas was making five-meg disk packs, despite the fact IBM, Burroughs, Honeywell and other major computer makers said no one would ever need that much capacity.
These days he heads up the Colossal Storage company which aims to make Colossal Atomic Holographic DVR disc drives, each one of which would be equal to a 10,000 to 100,000 Gigabyte disk drive.
Think about it.
"Thermal stability is paramount to good data storage," he told p2pnet.
"All disk drives rely on the disk media to store data so their data heads can accurately read information preventing soft or hard read data errors.
"CD’s and DVD’s use 2D bits and grooves in the tracks to represent 1 and 0’s. The pits and grooves allow light from the head to reflect off the mirrored surface underneath the pits and grooves back to the head. If there’s no pit or groove, the light doesn’t get reflected back. Data errors aren’t generated by thermal expansion of the disk unless there’s some out’gassing of the plastic substrate, causing the reflective surface to become distorted, preventing reflection of the light back to the head."
Optware proposes to use the pit and groove surface of the CD/DVD as a servo or positioning system for their data, says Thomas.
But there’s a very large fly in the ointment, he states.
"The thermal expansion of the holographic plastic polymer recording layer and the aluminum coated plastic substrate offer real opportunities for data soft/hard read errors.
"The materials in the different layers have variable rates of thermal expansion properties making it highly unlikely error free refractive data recording can occur over time."
Holographic polymer recording uses long polymer chains to cause light to refract off the molecules in many different nanoangles representing images stored in the internal geometry of the plastic polymer, Thomas explains.
Phase shifted data for optical storage is read in the gigahertz range and therefore the slightest variation in the frequency will cause read errors.
"For the photo polymer layer, gap layer, mirror layer, aluminum reflection layer, and substrate layer to work in unison the materials must expand at the same rate which they don’t. The data will become washed out over time.
"Optical frequencies in the nanometers make it imperative to have disk thermal expansion of data information and track position change uniformly."
A good example is hard drives using the same magnetic material for position information and data information, he goes on. The thermal expansion of the magnetic media is always uniform and linear over any temperature. That’s why temperature shifts don’t affect the writing and reading of data on a hard drive.
"Colossal Storage uses the same molecules for both data and position information having uniform thermal expansion over any temperature," says Thomas.
"Due to the complex lenses and mirror system used by Optware it makes even more imperative that the head to disk interface have a 0 % error factor.
"In my opinion, Optwares fails in their attempt to keep their holographic data and track information stable allowing soft/hard errors on their disk."
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See:-
the future - Alliance Hypes Holographic Revolution, DVD-Recordable, February 8, 2005
holographic storage - Radical disc storage increase, p2pnet, February 4, 2005
100,000 Gigabyte – Every file you ever owned on 1 disc, p2pnet, February 25, 2004
