What's Holding Back DVD-RAM?

Is it the threat of tape technology, or is it the lack of a true UDF (universal data format) standard?

Despite moderate success, DVD-RAM jukebox technology has really not taken off yet. "The frenzy is just starting," said Scott Leif, president of Globalstor Data Corp. (Chatsworth, CA). "I think that VARs will try to address nearline storage issues. DVD will become one of the preferred methods for nearline storage where WORM technology is not a priority. But the market is still very young."

There's no doubt that the DVD-RAM market will improve with time. And with the next generation of DVD-RAM due out by the end of this year, capacities will increase as the price stays the same.

Challenges To DVD-RAM
However, there are still several substantial challenges facing DVD-RAM. The first involves the threat posed by tape. Once upon a time, the advantage of optical's true random access created a distinct line between optical and tape. However, improvements in tape performance have narrowed the gap and increased the pricing pressures on the optical vendors.

For example, tape technologies such as Sony's AIT-2, LTO (linear tape open), and Quantum's SuperDLT are all going to compete with DVD-RAM in the nearline storage space. This is especially true in high-capacity applications (defined as greater than two terabytes). If a user can afford to wait 20 or 30 seconds for a file to be retrieved, then tape will offer the same capacity as DVD-RAM at half the price.

A "Shaky" UDF Standard
And there's another challenge. According to Globalstor's Leif, "The UDF (universal data format) standard is still shaky. UDF was primarily developed for the PC world. Bridging the gap between UDF for PCs (or Macs) to UDF for UNIX is going to be a big challenge. There are a number of vendors working on the problem, but it will take 12 months to 24 months before the problem is solved.

"Magneto-optic (MO) has been very successful in the UNIX space because it is plug and play as a stand-alone drive," he continued. "You can take those MO disks and migrate them into library applications. DVD does not have the same luxury."

Chris Stone, VP of marketing for Asaca-Shibasoku (Golden, CO), agrees that the current situation involving UDF is problematic. But, he doesn't believe that it's holding back jukebox sales. "The issue is that UDF is slow. Anytime you have software that can be read by anything from a Mac to a UNIX machine, you're going to have performance issues. There's simply a lot of overhead when writing to the disk."

For example, Stone said if you turn off the verify function when writing to a DVD-RAM library, the throughput is approximately 1.3 MB per second. "If you use the verify function, you're down to 600 KB per second," he said. "If you run UDF, you run at about 150 KB. But there's good news. If you're running a library, you don't need to run the UDF — unless you expect to remove the media for distribution. But people don't buy jukeboxes for distribution; they buy them for throughput."

Stone added that, if customers really need the removable feature, they can drag the information over on Windows explorer and make it into a UDF copy. Then they can bridge it out to a stand-alone drive outside the box.

A Matter Of Time
Therefore, is the lack of a true UDF holding back the market for DVD-RAM libraries? Stone says no. "I don't think the libraries are affected one bit. And the UDF drivers are getting faster and faster. The second version was three times faster than the original — so I think they'll get there. They just need more time."

Mike Downing, contributing editor