Digital Versatile Disc: The Next Generation of CD-ROM

© Roger Hutchison, Ph.D.
Golden, Colorado
January 25, 1997



DVD is about to hit the marketplace with a roar not seen since Fall `84, when "compact disc read only memory" or CD-ROM made its debut. DVD promises the next generation of CD technology with higher capacity and more "versatility" than previously available with CD-ROM, or with CD Audio, or with CDI.

What is DVD?

Digital Versatile Disc designed for two markets. The first and perhaps most immediate is the motion picture industry replacement technology for VHS. With a DVD drive and a playback system for television, users can see MPEG-2 quality video and hear AC-3 sound on a TV set. With DVD recording, and so-called erasable DVD or erasable CD-ROM, the home entertainment marketplace may have a true replacement for VHS recording and playback. This is the imminent market for DVD the home entertainment replacement technology for VHS. However, with a current projected price tag of $45.00 for a blank write-one-time DVD CD-R, it is unlikely that the recording part of DVD home entertainment replacement technology will offer an immediate threat to the pervasive VHS marketplace. Remember Beta? It was technically superior to VHS but lost the consumer war. Will we see DVD, a far superior technology, enter a similar war? Time, and not much of it, will tell.

The other use of DVD is for replacement of the current CD-ROM technology. This in initial stages will be more a compliment than a replacement. Does DVD signal the end to CD-ROM as we know it? When I look into my Delphi crystal ball, I don't see CD-ROM going the way of, say, vinyl records. What I see is a 10- to 15-year life cycle for CD-ROM in developed countries and an even longer life cycle in developing countries especially those with poorly-developed telephony.

In its first iteration, DVD-ROM shipped in March 1997 will be for high end-users who need more of what they already have. More space for games; more space for movies; more space for data simply more of what we already have.

An obvious question worth asking given the general confusion of the industry and the very big squabbles which have occurred in the previous year of hype did I say that? is just how big? The answer, at least for DVD-ROM, is 3.90 gigabytes for the recordable DVD-CD-R, and 4.7 gigabytes for commercially-pressed discs. You might then ask: Why only 3.90 GB for CD-Rs, and 4.7 GBs for commercial DVD-ROM discs? The answer is overhead. If you take a moment and do some quick calculations, you'll discover the overhead for DVD CD-R is as much as the capacity for a current CD-ROM about 700 MB. Now that's what I call overhead.

This first generation of DVD-ROM will be single sided and single layer. The DVD-ROM drives will be able to read two layered discs, which will hold upwards of 8.7GB of data but they will not be widely available if at all for the first year of DVD roll out. If the marketplace continues to evolve, as I feel confident it will (another Delphi forecast), we will soon see (1998-1999) double sided double layered DVD discs with a whopping 16.5 GB of capacity. Of course, the amazing thing is that this will all be on a silver disc which is 12 cm wide the same size as that now old-but-trusty CD-ROM.

One very important and interesting aspect of DVD-ROM is that the file and volume structure for data for DVD-ROM is the same as that for CD-ROM. It is based on the same sub-standard currently in use for ISO-9660 and is called ISO 13346. File access programs, indexing schemes and routines, as well as compression processes (see CRI-X3 on our CD-ROM Inc. Web site) currently in use on CD-ROM will be upward compatible with DVD-ROM. Simply put if you can compress data on CD-ROM, you will be able to compress and access data on DVD-ROM.

Should you throw away your CD-ROM drives and discs? Not a good idea. DVD drives will be downward compatible with reading the current generation of CD-ROMs. If you have a CD-ROM disc today and put it in a DVD player tomorrow, then the DVD player will read the CD-ROM. However, the reverse is not true. A CD-ROM drive today will not have the guts, so to speak, to read a DVD disc. DVD drives will also read CD Audio discs. However early buyers beware the first generation of DVD drives will not read CD-ROM CD-Rs, but will read DVD-CD-Rs expected to hit the road this June.

All this makes me excited. I haven't been this excited since taking the name CD ROM Inc. as a company name over eight years ago. Pretentious at the time, it was a good guess that CD-ROM would be a very important industry. Now, with the advent of DVD-ROM, I have that same funny feeling again in my belly DVD-ROM is as important if not more important to the future of the optical industry as CD-ROM was in 1984. It is a very welcome and encouraging development.

Where will we be as an industry in 10 more years? We still have more places to go and more capacity to exploit than ever before. In fact, we have more than 10,000 times greater capacity to exploit on a CD disc, even after DVD, than we do today. That makes CD-ROM by whatever name you want to call it a viable technology for many decades to come.

Roger Hutchison is President of CD ROM, Inc., the oldest privately held CD-ROM company in the World. He can be reached at rshutch@cdrominc.com or through his Web site at www.cdrominc.com