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

maybe Im not getting it

[COMON$]

But how is this different than current dual layer DVDs? Does it just take advantage of shorter wavelengths or what?

Re:maybe Im not getting it

[drinkypoo]

But is that really true? Is there significant degradation? VHS causes degradation during every play cycle not because you use the same device to read and write, but for two reasons: One, your VCR creates EM fields and VHS uses analog magnetic recording. So any time you put a tape in your VCR you're erasing it a little, whether you play it or not, just because there's a transformer in the same metal box as your tape. Two, the head in your VCR does helical scanning. Since the head therefore has to be round, so that 1) it can spin and 2) as it spins the distance from the axis of rotation to the tape has to remain constant, the tape also must describe a round path. The only way it can do this is if it rubs something so it might as well rub on the head. It pretty much has to anyway, because at the time it was outside our technical ability to use a much stronger signal - which probably wouldn't have been a good idea with analog recording anyway. The result is that the head physically wears away some of the coating as the tape passes the head. This is true of any system in which the recording medium contacts the read head, but it's especially true of VHS because you have a rapidly rotating head to deal with.

As an aside, this is why you should never pause VHS unless you're actually trying to see something paused, and then you should unpause it as rapidly as possible, because otherwise you're stopping the tape but not the head, and the head will sit in one place rubbing away the magnetic coating on the plastic tape. This is why you should never rent porn on VHS, all the good parts will be missing :D

Anyway, back to the topic at hand. I know this is not directly comparable for some obvious reasons, but I want to bring up Minidisc. While Minidisc is a MO drive and thus uses a substantially different technology, it might be worth discussing. MO works by using a laser to heat a very small region of the disk to the Curie Point, and then you write it with an electromagnet as it cools. Nothing happens below the curie point. Now, I know far less about CDR or DVDR than I do about this, unfortunately, but AFAIK it's based on the intensity of the laser, right? So here's my question, is there actually any significant degradation when you use the laser to read, or is the power level so much lower that there's really just not enough energy to cause it?

Re:Cost?

[Anonymous Coward]

If you have a terabyte of data to store I'm guessing you have plenty of disk space already. Maybe you don't have an empty file system with a terabyte of free space to do disc to disc copies but eventually disk space cost will come down to something reasonable for that amount of data.

Jim

Slow I/O???

[Sargeant Slaughter]

If this is using essentially the same technology as DVD i think the read/write speeds would be awfully slow to handle 1 TB of data. If the bits are squeezed into a smaller surface area (instead of just layerd on top of eachother) if should read faster but if the space the bits take up is the same I think it would have simial I/O performance. After all, you can only spin a disc so fast (10-15K RPM).
Unless they find a way to read/write to multiple layers simultaneously and very efficiently, I think it would be really slow. At round normal DVD I/O speeds, burning one of those suckers would take like 60 hours!
Universities like to announce stuff like they are a big breakthroughs when in reality they have little to no impact. Get's their names in paper...

They a revolutionary jump just to stay relevant

[Phat_Tony]

I remember when the first computers with DVD-ROM's started showing up, the computers generally had about 200-400MB hard drives. So a single 600MB CD disk held more than everything on your entire hard drive.

Now a standard computer might come with a 160 or 250GB hard drive, and where are disks? Only at about 8 GB for DL DVD's. Instead of fitting one or two hard drives of info on a single disc, now you fit 20 or more discs onto a single hard drive.

Yeah, I know Blue Ray and HD-DVD will be in computers soon, but they don't come close to reversing the trend. Soon we'll have 25-50 GB/disc, and by that time probably at least 500GB-1TB standard hard drives. And then it'll be a long time with frequent hard drive upgrades and no bigger discs again. Blue Ray and HDDVD may be bigger, but at the rate they're getting bigger, discs are still falling farther and farther behind.

I hope there will be some revolutionary increase like holographic storage discs, but I'm not holding my breath, because I remember reading articles about how we'd have terabyte holographic storage devices in a few years going back as far as NASA in 1993 and 4D around 1997. Holographic storage seems to be one of those technologies like fusion that are always a few years off.

At least holographic storage is always five years away, while fusion is always 20 years away. At least that sounds more promising.

Re:Next Voyager mission?

[Sylver Dragon]

I would just about kill for this sort of data density at the moment. I run a 4.5TB SAN at my office, and we're doing everything we can to free up space. A large part of the problem is that we have some very large datasets which are not needed regularly, but they are needed occasionally. Our current answer is tapes (we're getting a tape library which uses LTO-3 tapes soon) which work quite well, but they do degrade with time and don't handle being dropped well. Also, at $50 a tape, they can get expensive, and they are slow. Lastly, if you ever switch backup software you might have to deal with converting tapes to a new format.
We have actually used stacks of DVDs to backup some of the less used data, but at 8.5GB per dual layer DVD backing up a 100GB folder takes a lot of them, and is slow. Bring on the 1TB discs, I'll put them to use, and probably start complaining about how small they are soon.

Re:A Terabyte... For How Long ?

[PoderOmega]

I have some burned CDs ranging from 1-8 years that have just been sitting in the dark in a CD binder. Visualy they look fine and I am still able to pull data from them without problems in the rare case I pull something off them. Are you leaving your CD-Rs in the sun, swapping them in and out of drives? Some of my music CD-Rs that get frequent use are not looking too good. One thing about my older CD-Rs is the look (the new ones are slightly translucent) and feel thicker than the newer ones I have purchased of the same brand (Imation).

same thing as two-photon microscopy

[lukesl]

This is the same idea as two-photon microscopy, a relatively common technique in biological sciences. Basically, the advantage is that it gives you very good resolution in the z dimension (not just x and y). This allows you to image deep into biological tissue, or apparently, into multiple layers of an optical disc. It's not exactly a new idea, and the technology is mature. The question is whether or not it can be made affordable--a low-end titanium-sapphire laser costs around $130,000, and they have to be physically large enough to accommodate several meters (IIRC) of optical path length. The development of laser diodes with high enough intensity to do two-photon excitation will probably be the limiting factor in bringing this to market, not the dye chemistry.