Fluorescent technology could expand horizons for disk storage

J.B. Miles

Is the king dead already?

I recently wrote that DVD is probably the best PC storage solution to date [GCN/Shopper, August, Page 12], especially for individual users. I was impressed with the very flexible read-write capabilities of DVD, along with its storage capacities of up to 17G per dual-layer, double-sided disk.

But then I heard about an even newer optical storage technology called fluorescent multilayer disk, or FMD. A GCN reader sent me an e-mail note saying it dwarfs DVD in potential capacity and advising me to check out a start-up company, Constellation 3D Inc. (C-3D) of New York, and this new technology.

I don't usually pay much attention to tips about purported revolutionary technologies by start-up companies, but this time I did, and I'm impressed.

According to Tom Prate, storage technology manager for Dell Computer Corp., the main criteria for selecting any removable media device for a PC should be capacity, speed, convenience, durability, data availability and backward-compatibility. Before FMD, I thought DVD technology had covered these criteria better than any of its competitors. I even went on record predicting a long and bright future for DVD.

I'm not about to recant that statement entirely, but from what I've seen of FMD, I think it could catch DVD within a year, or as long as it takes C-3D and its partners to ramp up some production drives.

Here's why.

CD and DVD disks store their information on only one or two data layers within their hard plastic coatings. CD-ROMs contain one storage layer that can be reflected by an infrared laser beam to deliver up to 650M of storage. DVDs also use a laser on up to two layers on each side of a disk, for a total of about 17G of storage on a double-sided disk.

It is difficult to create more storage layers in either CD or DVD disks because of inherent limits on capacity in both technologies. Light from laser beams is spread across the reflective layers of CD and DVD disks, scattering randomly and causing interference between data layers. If more than two layers per side are used, the signals degrade to an unacceptable degree.

FMD technology doesn't have those limits. Each storage layer is coated with a transparent fluorescent material rather than the reflective metallic layer of a CD or DVD. When the laser beam hits a data mark on the layer, fluorescent light is emitted. Because this light has a different wavelength from that of the laser beam, it is 'incoherent' in nature'in contrast to the reflected light of CD and DVD devices'so it can pass through multiple data levels undisturbed.

C-3D claims it is feasible to design FMD media with up to 100 data layers for storage potential of hundreds of gigabytes on a single card or disk. Since each data layer can hold 4.7G of data, that's a huge potential for storage. When blue laser technology, which uses a shorter wavelength than red lasers, is perfected, the company says one of its disks will hold up to 1T.

The company is working on first-generation FMD ROM disks and drives that will hold 20G to 100G of data on 12 to 30 data layers. C-3D says parallel reading and writing technology will allow data transfer speeds exceeding 1G per second, depending on the application.

Because FMD disks are designed around the same form factor as CD and DVD disks, the same basic drive designs with some modifications should work.

Other FMD applications include replacements for commercial movie reels on a single CD-ROM-sized disk, Internet content streaming and data warehousing.

C-3D is working out partnerships with some drive manufacturers to begin production of commercial units as early as next year. See the company's Web site at for more information.

What's next? Holographic storage. But that's light years away... maybe.

J.B. Miles of Pahoa, Hawaii, writes about communications and computers. E-mail him at [email protected].


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