Why The CD Tower Crumbled.

As towers go, it wasn't very impressive. The Eiffel Tower's taller; the Tower of Babel's more fabled; and the Leaning Tower of Pisa ...well, let's just say it sustains greater angular momentum.

But what about the CD tower? Only a few years ago, a rack of six or seven CD-ROM drives, each spinning a single platter, was the epitome of CD storage. With no robotics to impose delays and every disk sitting right under a read-head, everything in a tower was on-call all the time. It offered practically instantaneous retrieval of any file from enormous databases.

The killer app for CD towers was the otherwise humble telephone directory. Database engines accessing a six-disk tower had more than 3GB of data at their disposal. Users could type in a name and the software could display that person's (listed) phone number. With almost no extra effort, it could perform cross-directory searches, too, such as finding all the phone numbers installed at a given address or generate a selected list of numbers based-on specific criteria.

Of course, towers weren't cheap: their cost being a multiple of the price per drive at a time (the early 1990s) when CD-ROM drives cost a few hundred dollars apiece. But there were some tradeoffs that made towers cost-advantageous. Unlike jukeboxes, towers had no other moving parts, so support expenses were negligible. Other than time spent replacing disks (which, for a phone-directory, might happen only once a year), there was hardly ever a need to take a drive off-line. Almost every tower enabled administrators to do what's now called "hot-swapping" to replace any drive in the tower without shutting down or interrupting the activity of the others.

If there was ever such a thing as a "passive" storage peripheral, the CD tower was it. You set it up and you left it alone.

A CD jukebox, by comparison, with its racks, gears, pickers, and doors is a Rube Goldberg invention that can't be left alone for long. (I'm not talking about reliability and MTBF statistics-- I mean simply that managing a jukebox is an ongoing process requiring human attention; someone always has to add or remove disks, or check to see why some disks are more frequently-requested than others, etc.)

Jukeboxes proved to be a better investment than towers, though, because they could hold ten or 20 or even 100 times more disks than towers could. Where towers did beat jukeboxes was in retrieval times. Even a 50-disk library will force users to wait in a file-retrieval queue that can sometimes seem interminable. For administrators and managers, the high capacity of jukeboxes outweighed the faster retrieval time of towers. The loss of productive time while users were being inconvenienced was less important than obtaining storage at a lower cost per megabyte. Jukeboxes were simply a better investment.

But what users really want (as if you didn't know) are both: rapid access and high capacity. And that came about with the addition of a hard disk drive to the jukebox's front end. Once that happened, the tower was doomed. Even the earliest configurations at a time when HDDs cost more than a dime-a-megabyte were more cost-effective than CD towers could ever be. As the price of hard disk storage trended downward, RAIDs became even more attractive than single HDDs. Today's RAIDs can easily hold 10-20 percent of a jukebox's capacity for only about a nickel-a-megabyte.

Interestingly, the "SolidState Disk" (SSD) hasn't risen to the occasion, except in some key applications. SSDs are much faster than HDDs; so, theoretically, they should be more attractive. But SSDs cost far more: about $5/MB. For the steady or predictable retrieval of large or rarely modified files such as document images, HDDs are certainly fast enough. SSDs, however, are better suited to tasks that require manipulating and/or updating many small files almost simultaneously, which is what happens in applications such as electronic funds-transfer and the processing of other commercial transactions. The cost of SSDs is falling, to be sure; it's likely that jukeboxes optimized for video and multimedia applications may have SSD caches, soon, rather than HDD caches. But SSDs will always be more expensive than HDDs. By the time SSDs approach $2/MB, HDDs will cost only a few pennies per megabyte.

The arrival of DVD-ROM has also doomed the tower. The same telephone directory that previously needed three or four CDs to hold it can now fit easily on a single 4.7GB DVD-ROM disk; and read-only DVD-ROM drives, which cost only about $100 more than CD-ROM drives, can also read CD-ROMs and CD-Rs and CD-RWs.

Installing DVD-ROM readers in a jukebox adds relatively little to the cost. Installing DVD-RAM drives (or DVD+RW, when they arrive), adds record-ability and rewritability for a few hundred dollars more per drive. But recordable DVD drives also read all the replicated DVD formats and all the replicated and recordable CD formats, as well. One size really does fit all.

So the tower, attractive as it once was, is now only an empty shell: a stepping-stone on the path toward... oh, to heck with the metaphors! You will never see--or need--a "DVD tower."

Is There A Killer-App For DVD-Writers?

For what key purpose will DVD-recordable technology be essential? Will there be a single, easy-to-grasp and indispensable application (a so-called "killer-app") that, in effect, forces users to go out and buy DYD-writers and recordable DVD media? That was the subject of a lively discussion at the DVD-Pro conference in August.

Everyone acknowledged that, once practically every computer had a CD-ROM reader as standard equipment, the killer-app for CD-recordables was file-exchange. Hugh Bennett, president of Forget Me Not Information Systems and a columnist for magazines published by conference host Online Inc., noted that "All the read-only DVD-ROM drives today, and all the DVD-writers too, can read all the CD formats; so CDs aren't going away any time soon. And don't expect any of the competitors to be a 'messiah' format that will somehow lead users away from CD and into DYD. The irony of the DVD-recordables is that there was no obvious market for them before they were developed. Matsushita and Hitachi and Toshiba have positioned their DYD-RAM system as a challenge to MO, but MO never ruled the world the way CD does; MO is not a best-selling format like [Iomega Corp.'s] Zip, that needs to be beaten. Hewlett-Packard and Sony and Philips say that their DVD+RW is a 'Jaz-replacement," he continued, referring to Iomega Corp.'s 1-2GB ma gnetic Jaz disk system. "But they've shot themselves in the foot by pre-announcing it and then taking two years to release the first product. Pioneer says its write-once DVD-R is intended for DYD-ROM prototyping and content development," he went on, "because their DVD-R disks can supposedly be read by today's DVD-ROM drives. But only DVD-R disks that are formatted to mimic DVD-ROMs can be read in DVD-ROM drives--not DVD-R disks that are `packet-written.' So the three competitors may divide up the market into niches for a while," said Bennett, "but if they want the kind of market penetration that CD-writers have, they'll have to cooperate eventually. And I'd hate to see that take five years."

Audience member Sharon Viger,. HP's product marketing manager for DVD+RW, told the conference that "Format compatibility is the key to solving consumer problems. It's what will make users want to do things, like move their home video tapes onto disks. We call that application the `long-term storage and sharing memories.'"

However, session moderator Steven Nathan disagreed. "That kind of consumer app is pretty far off," he said. "If someone wants to keep old video images of their kid's first-birthday party, they'd do better to re-record them onto a fresh VHS tape."

Is The "Format War" Already Over?

Felix Nemirovsky, chief technical officer at Plextor Corp. (a CD-ROM and DVD-ROM drive manufacturer) isn't worried about format competition fragmenting the market. "Let them fight it out!" he declared. "I was born in a Communist country, so I don't think people will be happy with just one format. But it's true that neither DVD-ROM nor DVD-RAM chives are selling as well as we [in the industry] had hoped or expected. So I think we should develop 'combo' drives that read DYD-ROM hut also record CD-R and CD-RW The killer-app for DVD-recordables has yet to be developed," Nemirovsky insisted. "More and more applications are emerging. And when the killer-app comes along, and it's big enough, then one DVD format will be more successful than the others, because it will suit that application best."

However, Lou Skriba thinks the killer-app is already at hand. "It's recording off the Internet--all those pages, all that streaming audio and video," said Skriba, who's a storage industry veteran and now president of Gig Media Productions.

"And I'm going to stick my neck out and say that the 'format war' is over," he added. 'There's no confusion in the marketplace because the public doesn't even know about rewritable DVD anyway. The winner is DVD-RAM because it's had two years' head start. Matsushita has about 800 patents, including some critical ones, like land-groove recording, which enable DVD-RAM to achieve very high bit-density. Some 300 companies are claiming at least some level of support for DVD-RAM already; and the three DVD-RAM manufacturers have shipped half a million drives--100,000 of them into the U.S. alone."

Skriba stuck his neck out even further when he added, "I think that DVD+RW may be merely a 'place-holder' for [developers] Sony and Philips. They'll offer it for a while, of course, but they have major R&D operations in Japan and the Netherlands [respectively]. In a couple of years, they could release something that will leap right over DVD."