Charting a path for optical storage
Charting a path for optical storage
Blu-ray technology has given the optical storage market a new lease of life. David Braue reports.
Ratification of version 1.0 of the BD-ROM physical data specification in early August marked a watershed moment for the Blu-ray Disc Founders (BDF), the group of companies overseeing development of the next-generation Blu-ray optical disc format. It was also another nail in the coffin of conventional magneto-optical (MO) discs, whose once-spacious capacity has become less and less remarkable as other optical formats emerge.
MO discs were never intended as mass-market storage; rather, their cartridge-based design, complete with shutters to keep out dust and prying fingers, was built for longevity. That has made it popular amongst government organisations and companies in heavily regulated industries such as demographic or land title registries, where data must be preserved for decades in an accessible format. Write once read many (WORM) capabilities were also an important element in the move from paper to digital document management, since WORM capabilities could ensure that data on archived discs had not been tampered with.
With an average cost of around $80 per 9.1GB cartridge, however, MO has begun to look far less attractive to companies struggling to manage steadily increasing volumes of data-particularly with commodity DVD writers costing just a few hundred dollars and 4.7GB discs available for less than $1 each. Niche DVD-RAM discs have held a comparable 9.1GB since their inception, and the recent introduction of dual-layer DVD discs storing nearly 9GB each has raised the bar to the point where capacity is no longer a differentiator for MO.
Ian Selway, information lifecycle management marketing manager with HP Australia, concedes MO is 'end of life' technology but believes its successor-UDO (Ultra Density Optical) discs-will soon pick up where MO finished off. Designed by a consortium that originally included HP, Sony and Plasmon, UDO discs use blue laser technology-also at the core of Blu-ray discs-but include a cartridge-based design targeted specifically at the corporate market. First-generation UDO discs store 30GB per cartridge, but this will increase to 60GB in 2006 and 120GB by 2008.
While it's clear that blue laser technologies will chart the future of optical storage for years to come, which format wins out remains a question of some speculation. Broad industry support will clearly make Blu-ray the standard for consumer-level entertainment. However, corporate and government customers will need to choose between incompatible UDO, Blu-ray and PDD (Professional Data Disc), yet another incompatible format developed by Sony after it defected from the UDO development effort.
PDD is rated at 23.3GB of storage, with transfer speeds of around 11MB/sec-half the speed of Blu-ray's rated 24MB/sec and slightly faster than UDO's 8MB/sec. Sony is positioning PDD in several distinct industries, with broadcast, IT and eventually desktop drives designed with different performance characteristics. PDD will not, however, target the mass market: Sony will follow the audio-visual industry by positioning Blu-ray in that space.
Too many choices
Format wars are nothing new for Sony, whose Betamax videotape format dominated broadcast reporting for two decades but was whitewashed by VHS-based competitors. And while PDD will certainly find support among many OEMs in niche markets such as healthcare, it will face a formidable enemy in both UDO and Blu-ray standard disks. As all three technologies mature, corporate users will need to decide whether it still makes sense to buy specialised optical jukeboxes, shift towards lower-priced and mass-market Blu-ray technologies, or pursue a completely different strategy.
Each approach has its merits. CDs and DVDs, for example, were once thought to be indestructible but have since been shown to be potentially prone to data loss due to oxidisation in poor-quality media. Additionally, their cartridge-based design should make them somewhat more durable than carrier-less discs, which can become magnets for fingerprints, dust and scratches. Sony PDD drives, for example, offer a completely airtight design.
Whether Blu-ray's mass-market design means that it offers better permanence than DVDs remains to be seen-discs are still scarcer than hen's teeth and are so new that nobody can speak authoritatively about their lifespan-but UDO and PDD have, on paper at least, been engineered to higher standards.
Selway, for one, has his doubts about Blu-ray's suitability in corporate environments: "As long as consumers are looking to drive down the price of media, at the end of the day the quality of that media suffers," he says. "When you're making media to a price, it has to suffer."
Volume will also be a factor in determining the success of UDO and PDD, however: most corporates have, after all, ignored optical media altogether and focused on high-density tape for backups and archiving. If the penetration of MO drives is any indication-Selway concedes that HP sells just 'ten to twenty' MO jukeboxes per quarter in Australia-any technology seeking to occupy its market will struggle to reach critical mass.
That could eventually push corporates towards Blu-ray, which will satisfy the need for WORM functionality in many records and document management applications but will benefit from heavy industry investment in R&D. If current jukebox designs are anything to go by, Blu-ray will enable truly massive storage density: Plasmon's DVD-RAM based D-Series libraries, for example, support from 80 to 2175 slots to deliver up to 20TB of storage. Similarly sized libraries using Blu-ray drives would provide up to 110TB of storage per jukebox.
Future planning
Simply increasing data capacities using new technologies won't free businesses from the problems of storage management, however. Although conceding that existing MO users will likely stick with the technology they know, companies considering optical storage for the first time should also consider using better established tape or disk technologies, according to Graham Penn, Asia-Pacific director of storage research with IDC.
The problem lies not in the advantages of one technology over another, Penn explains, but in the sheer volume of disks that needs to be managed-and the requirement for specialised software and equipment.
"The market is moving away from getting into optical," he says. "It's become impractical to do disks. Commodity storage becomes a burden once you get beyond a certain number of disks that you're trying to tag and identify. Finding the one you want is invariably the problem, which is why people operating in the big end of town are looking for systems that don't have losable media."
Long-term data accessibility is also an issue. Future generations of UDO will be engineered for backwards compatibility with MO and earlier UDO iterations, while drive compatibility with DVD and CD formats is held to be critical for Blu-ray adoption. Regardless of format, however, Penn points out that every disk design is eventually going to be rendered obsolete; companies need to anticipate this and build a technology refresh strategy into their operations cycle.
Simply planning to copy all past data onto modern storage media every five years or so is one strategy, although the manual costs involved are considerable. Rather, long-term archiving means implementing an ongoing method of data preservation in a commonly usable format-and that might just as well be paper, Penn argues. Although it's not viable as a primary method of data storage, he says, paper makes an excellent archival medium: it's been proven to last more than 500 years and can be extended even more using climate control, acid-free stock and other modern techniques.
Ultimately, the choice of optical format will be determined by the application. While high-volume optical technologies will be adequate for many companies, specialised applications may still require the careful engineering and permanence of specialised cartridge-based optical media. The key is to plan an exit strategy as well as an entrance strategy, so your data never gets stuck where you can't get to it.
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