A Terabyte of Data on a Regular DVD?

Roland Piquepaille writes "This is the promise of the 3-D Optical Data Storage system developed at the University of Central Florida (UCF). This technology allows to record and store at least 1,000 GB of data on multiple layers of a single disc. The system uses lasers to compact large amounts of information onto a DVD and the process involves shooting two different wavelengths of light onto the recording surface. By using several layers, this technique will increase the storage capacity of a standard DVD to more than a terabyte. Read more for additional references and a diagram showing how this two-photon 3D optical system reads data."

Comments

Article is wrong

[Andy Dodd]

By the definition of a DVD (yes, just like the various "color" Book standards that defined CDs, there are standards that define DVDs), this new technology will not result in a standard DVD by any means.

More proper terminology might be "in a standard form factor 12cm optical disc".

Re:light on details...I'm a skeptic

[drinkypoo]

and finally, due to the nature of holography (in that small sections of a hologram contain the information needed to reconstruct the entire hologram), a disc with holographic storage should be much more resistant to read errors resulting from scratches, whereas with one of these, a scratch could render data on several layers unreadable.

You are incorrect - you're almost right but your interpretation of the durability of a hologram is unfounded.

Small portions of a hologram contain the information needed to produce an approximation of the original image. The difference between traditional and holographic storage is that a scratch on a CD renders the information under the scratch unreadable, while a scratch on a hologram degrades the entire image.

In other words, you lose just as much data, it's just unevenly distributed. In the end, it will help you with durability by making it so that a certain percentage of the disc must be damaged before the data is unreadable; but at the same time, if you start with a 10cm square hologram, and you want to be able to still read the data faithfully if you only have 1cm square area left, your data will have to be written across 100x the area that it normally would in order for you to be able to read it out later.

If a 700MB CD without ECC is 800MB then an audio CD is ostensibly one-eighth error correction. Assuming the same density, you would get the same amount of data on the CD, but you would still be able to read data from any part of the CD as long as no more than 1/8 of the media was destroyed. In theory you could drill some symmetrical, balanced holes in such a CD (assuming a rotating-media holographic system, which is probably not a safe assumption) and lose nothing, not even the data you punched out.

Anyway, the REAL problem with optical disc durability is that the top layer is vulnerable. Scratches on the bottom can be polished out and minor scratches don't even have a significant effect because the laser is focused on the metal layer, not on the disc surface. It's diffuse when it passes through the layer where the scratches are. If the top of the disc were protected, I'd probably have lost about 50% less discs. I just had to throw about five discs away because their metal layer stuck to my CD binder and peeled off... And the first CD I ever killed died because I laid my arm across it for a couple minutes and sweated on it, which caused big chunky pieces of the metal layer to delaminate and stick to my arm like gold flakes.