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Dense Disks

Emerging 3-D holographic storage is poised to be the next great archival medium.

Most state and local government agencies involved in the archiving and preservation of large digital assets know a thing or two about data storage technology. But they may not know much about one emerging contender in the field: holographic storage.

The first commercial holographic storage products are slated for release in mid-2008. With first-generation products boasting write-once, read-many (WORM) characteristics, a lifespan of 50-plus years, initial disk capacities of 300 gigabytes per disk and a 20 megabyte-per-second data rate, proponents are aiming this technology at the long-term archival needs of government entities, highly regulated health-care and medical organizations, and professional media and film industries.

With their ever-growing data stores and their requirement to maintain many records in perpetuity, agencies would seem ideal users. But how will this new technology work, when will it be available and at what cost, and what are the hurdles to implementing it? Here's the quick-take response to each of these questions for would-be early adopters.

How It Works

As opposed to traditional 2-D disks that write data only on the surface of the media, holographic storage supports writing data volumetrically, or three-dimensionally, throughout the whole depth of a disk.

The technology turns data bits typically composed of zeros and ones into a unique dark/light "checkerboard" interference pattern. A spatial light modulator and the intersection of two laser beams (a signal beam containing the data and a reference beam) help create the interference pattern, which records as a hologram onto a plastic photo-polymer disk.

At an initial price of 60 cents per gigabyte, you can expect to see most storage vendors include holographic storage in everything from virtual libraries to storage arrays. The potential "green" factor of the technology is also intriguing: Early estimates suggest energy savings of 90 percent over traditional spinning disks.

The anticipated terabyte-plus capacity has one state archivist thinking the technology might offer a good alternative to the practice of copying records onto microfilm for distribution to other locations. "Due to the volume of data it could hold, I could see a medium such as this being a very viable and economical way to distribute some of this information to venues that may not have good Internet access," says Andy Taylor, assistant director of records and information management for the Georgia Archives. Taylor is currently helping to draft the policy and procedure surrounding the Digital Archives Project of Georgia. The project helps determine how best to ingest, preserve, replicate and disseminate digitally archived Georgia public records that are known to have a permanent, historical value.

Taylor says his organization is just at the start of the digital-archiving wave, noting many public archives still have a lot of ground to cover before they will be ready to make decisions about a technology like holographic storage. "Many public archives refrain from taking electronic records because they simply don't know how to deal with them. So a lot of this data may be, unfortunately, on an unmarked backup tape in the storeroom downstairs within the agency itself."

Issues still to be addressed include what type of records need to be archived online, Taylor says. He estimates the Georgia Archives will end up keeping some data online, then developing policy to move some of it to near-line storage over time, before ultimately sending it to offline storage.

Research and Development

The push to market holographic storage products will begin with InPhase Technologies, a Bell Labs spin-off in Longmont, Colo. Customers can expect to see holographic drives initially available for about $18,000, with holographic disks available for $180 each, says Liz Murphy, vice president of marketing at InPhase.

Murphy expects 80 percent of InPhase's ultimate sales of holographic drives and media to come from storage and media vendors that will brand the technology under their own labels. This will undoubtedly include many of the companies that InPhase is currently working with, including Maxell Corp. of America, Imation and others.

Engineers from Hitachi Maxell have worked with the company to develop and manufacture the media for InPhase's holographic storage solution, says Rich D'Ambrise, director of technology at Maxell. He sees holographic storage as a promising vehicle for organizations with long-term archival needs, especially for those needing to comply with state and federal guidelines.

Perfecting the materials and technology may require more industry muscle before the market sees multiple competing vendors, says David Waldman, chief scientist at DCE Aprilis, a Dow Corning subsidiary that develops storage technologies and materials.

"Incumbent [optical] technologies are already entrenched," says Waldman. "For a new technology to really make its play, you have to compete in performance and cost. That will require big consumer electronics companies to shoulder the significant development costs to make a [holographic] drive." He sees true competition coming to market in 2011 or 2012.

Agency Adoption

For now, organizations with heavy data-storage needs should watch these developments and consider adopting early holographic technology as a prototype test-bed to see how it works. This advice comes from Dr. Victor McCrary, who convenes regular meetings with industry and government technology officials for the Government Information Preservation Working Group within NIST's Digital Media Group. McCrary is also a business area executive for science and technology at the Johns Hopkins University Applied Physics Laboratory. McCrary sees the future of holographic storage as especially important for agencies that handle imaging data. "I think it has very good potential. Digital preservation is an issue that will only get larger in importance and concern, particularly for any sort of agency -- government or commercial -- concerned about retention of important records."

While that may be the case, it's also clear that the adoption of holographic storage may still take some time, given the current lack of awareness of the technology among target customers. Patricia Smith-Mansfield, director of the Utah State Archives, is one of many who has never heard of holographic storage before. To be considered, she says, holographic storage, like any other type of data-storage technology, would have to satisfy a few key criteria: "Assured access and preservation, including authenticity, trustworthiness and security."

Will holographic storage prove its merits in these areas? Only time and a few real-world installations will tell.

By the Numbers

The capacity of one first-generation holographic storage disk is equivalent to:

  • 462 CDs
  • 64 DVDs
  • 26 hours of video recorded at 25 megabits per second
  • Several million pages of text

How Holography Got Its Start

Hundreds of researchers in the private and public sectors have advanced the field of holographic storage, but its early beginnings were largely accidental.

Dennis Gabor, a Hungarian-born British physicist, came up with the theory of holography in 1948 while conducting research to improve the electron microscope. By combining two Greek words -- holos meaning "whole" and gramma meaning "message" -- he created the term "hologram" to describe his theory.

In 1971, Gabor earned the Nobel Prize in physics for his work and gained a loyal following of researchers who have since advanced breakthroughs in holography and holographic storage.

Mar 27 2008

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