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Optical storage sings the blues

Optical storage sings the blues

Conventional optical technologies such as CD, DVD and magneto-optical (MO) drives write data using red lasers. But makers of storage systems and recording media are developing ways to read and write using more efficient blue lasers. Because these lasers operate at shorter optical wavelengths, they can write more data in the same space and write and read data faster than devices that use red lasers.

Sony led the way when a consortium it founded last fall announced Blu-ray, a technology that can write 25GB of data on a DVD-size disc (a standard DVD holds 4.7GB). And Cambridge, England-based Plasmon is already shipping a first-generation blue-laser disc drive that boosts the capacity of a 5.25-inch optical disc from 9.1GB to 30GB.

Plasmon claims the price per gigabyte of its drive is 80 per cent lower than the prices of products based on conventional red-laser MO technology.

Competing camps

Most of the buzz about blue-laser technology has focused on the consumer electronics market, where blue-laser discs are seen as a successor to DVDs. The devices could also be used for backing up desktop PCs or archiving audio, video and image files.

Two industry groups are promoting incompatible formats: Blu-ray Disc Founders, a consortium of Japanese companies led by Sony and recently joined by HP and Dell, and the DVD Forum, led by Toshiba and NEC.

The high-definition DVD (HD-DVD) standard promoted by the DVD Forum is an extension of red-laser technology that uses the same disc form as conventional DVDs. Designed to maintain backward compatibility with existing DVD media, it uses the same bonded-disc structure as the current red-laser DVD and sandwiches the recording layer between two 0.6mm-thick plastic layers. A single-layer read-only disc has a capacity of 15GB, and a dual-layer disc supports 30GB.

The Blu-ray standard represents a more radical departure from the existing DVD format. While the disc is the same size as a DVD, the recording layer sits on the surface of a 1.1mm substrate and is protected by a special coating. A single-layer BD-ROM, as the Blu-ray Disc Founders call it, will hold 25GB — 67 per cent more than an HD-DVD — and a dual-layer disc will hold 50GB.

A senior vice-president at Sony, Mike Fidler, said the company would have Blu-ray media in both write-once and rewritable formats by year’s end and will ship a Blu-ray disc player by the end of 2005.

Blu-ray in PCs would follow roughly the same schedule, he said.

“HP and Dell look at this from both the entertainment and data-storage perspectives,” Fidler said.

Disc economics

The price of Blu-ray and HD-DVD drives and media will eventually come down to the levels of today’s red-laser devices and media, analysts claim, but users will see a much lower net cost per gigabyte of data stored. And that cost will continue to fall as storage densities increase.

Today, however, Sony Blu-ray recorders, which are available only in Japan, sell for $US2700. Discs are $US23 each.

It’s not clear which format will ultimately prevail. HD-DVD has lower capacity but is less costly to manufacture because discs can be made using existing DVD production equipment. Blu-ray proponents counter that although their manufacturing processes must be changed more radically, it will be cheaper in the long run to make a Blu-ray disc than an HD-DVD. Right now, PC users may want to place their bets with Blu-ray, since it’s the only blue-laser format to be endorsed by major PC makers so far.

For storage administrators who care more about data archiving than about downloading high-definition television footage, other blue-laser technologies are emerging.

For years, companies in industries such as financial services, healthcare, insurance and publishing have chosen optical media for archiving because they’re extremely reliable and long-lived. And because they can’t be erased or rewritten, optical media meet the most stringent government requirements for records retention.

When it came to enterprise storage, the amount of data stored on optical media would remain a tiny fraction of the amount stored on magnetic media for the foreseeable future, an analyst at Enterprise Storage Group, Peter Gere, said. But he predicted that the cost advantage of blue-laser media would feed a surge in popularity for write-once, read-many optical storage in the wake of new regulations and recent litigation related to data archiving.

“IT managers are hypersensitive to the risks associated with poor records management, and optical storage is the poster child for long-term data retention,” Gere said. “It may not be the fastest or the most cost-effective, but it is the best media right now in terms of ensuring long-term data retention.”

Plasmon’s blue-laser Ultra Density Optical (UDO) technology had really given optical a new life, he said. Optical storage was likely to remain somewhat more costly than other technologies, Gere said.

“But you are paying not only for longevity, but also for something magnetic media can’t provide, which is immutability,” he said.

Archiving applications

UDO drives and media represent another application of blue lasers, one designed specifically for professional data-archive applications.

UDO systems use the same 5.25-inch disc format as conventional MO libraries, but they use blue lasers and can store 3.3 times more data than MO discs can. Plasmon calls UDO a successor to MO. However, UDO is all-optical, whereas MO discs support magnetic storage on one side and optical on the other.

Although developed and promoted by Plasmon, the UDO specification was formally published and adopted in January by Ecma International’s TC31 Technical Committee.

Ecma is an industry association based in Geneva.

Although Plasmon sells DVD drives and media, Plasmon’s marketing vice-president, Dave DuPont, said DVDs in red- or blue-laser formats would see very little corporate use because they were more fragile and less reliable than UDO.

“We are finding customers are unhappy with DVD because it was never really designed as a professional archival technology,” he said. “All the people we talk to want to move away from DVD because the media is of uncertain quality.”

Last month, Plasmon announced that HP would use UDO drives and media in StorageWorks optical libraries.

The 5.25-inch blue-laser format would gain popularity because of its cost advantages over red-laser MO discs, DuPont said.

A new market was emerging as companies and government agencies demanded a way to store surveillance-camera images for long periods of time, not just for a few days, as was common before the recent rise of terrorism, he said.

Imaging systems reseller and service bureau, Digital Storage Solutions, scans documents for clients and archives the data to DVD or MO.

Director of the company’s storage division, Paul Greene, said he would migrate to UDO, probably this year.

“Traditionally, MO has been geared to professional archiving, and CD and DVD have been geared to consumer markets because the cost is so much lower than for MO,” he said.

“Now, with UDO, you get a much higher capacity per disc plus much higher reliability because it’s a jacketed media.”

Greene said a complete UDO system — including the library, media, magazines for handling the media, software and maintenance contract — would cost just slightly more than a DVD storage system.

“You may pay 10 per cent more upfront, but that’s spread over the life of the system, and you get much more reliability and longevity,” he said.

One of Greene’s customers, a service bureau, put in two Plasmon UDO jukeboxes a month ago and has seen flawless performance so far, he said. The Plasmon units replaced IBM jukeboxes based on 5.2GB MO discs.

The service bureau’s eight jukebox units filled quickly, and had been expanded from 1.3TB each to 19TB each, Greene said. The customer also gained about 30 per cent in read and write speeds over MO.

Sony recently announced its own line of 5.25-inch blue-laser drives and media, called Professional Disc for Data (PDD), but Plasmon was the clear leader in this market, Gere said.

HP and IBM use UDO in their storage systems, and Plasmon and HP have 94 per cent of the optical library market. So far, only Sony supports PDD.

“I’d say PDD is a niche product for those that are loyal Sony customers,” Gere said.

“I don’t see any major systems vendors lining up to support PDD.”


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