TDK Electronics has announced the creation of a technology alliance with Calimetrics, through which two companies plan to apply Calimetric's MultiLevel Recording (ML) technology to create a new recordable and rewritable optical disc format. The first drives to incorporate ML technology will be built on the CD-R/RW platform, and will have the ability to record more than 2GB at 36X speed on blank ML discs. The drives will also be able to record on current CD-R and CD-RW discs at 12X speed. "The drives will have the same functionality as current CD-R and CD-RW drives, as well as the ability to record on MultiLevel media," says Tom R. Burke, chairman of Calimetrics. "There will be two different kinds of disc media available, one based on CD-R, and another based on CD-RW standards."
Shades of Gray
TDK's implementation of Calimetrics' ML may draw comparisons to Double-Density CD-R, the Philips/Sony format announced last summer. The proposed drive designs are similar in that they write 650/700MB CD-R/RW, read all CD formats, and also write and re-write higher-capacity discs on different media that is only expected to play in the drives that write it and will not have a corresponding replicated media format. The formats are also backed by major players in CD-R/RW (in ML/CD-R's case, TDK, Plextor, and Mitsubishi). ML media is higher capacity than double-density CD-R (2GB versus 1.3GB).
But the real difference is in how the media is constituted and written. Double-density CD-R/RW discs will be written the same as standard-density CD-R/RW discs, with combinations of different-length marks and no-marks (equivalent to pits and lands on replicated CDs) of uniform darkness and higher reflectivity. However, with double-density CD, the marks are smaller and the grooves are more closely packed together. By contrast, in the TDK/Calimetrics ML format, 2GB discs will be written with marks of roughly uniform length and with different levels of reflectivity. The range of reflectivity (think of it as shades of gray) allows more values to be assigned in each mark, or "data cell." In conventional CD-R/RW and double-density CD-R discs, the possible values for each mark and no-mark are 0 and 1; in ML discs, values can range from 0 to 8. Thus ML-recorded discs can store more information in each data cell, which gives the discs higher capacity over their entire surface area.
The ability of ML drives to write at higher speeds (projected at 36X for the version just announced) comes from the larger amount of information their optical heads are able to write in the same amount of space as do conventional or double-density CD-R.
Joining the Bridge Club?
The foreseeable future of recordable disc technologies, of course, is writable DVD. High prices for both drives and media, as well as an array of incompatible formats have made DVD recording a thing for only the well-to-do. At best, writable DVD has yet to conquer the broad professional and consumer demographics as CD-R/RW. "There is a need for a bridge between recordable CD and recordable DVD technology," says Burke. "The need is for higher speeds and storage capacities, particularly for disk back-ups, video editing, and recording." For the average consumer, 650MB is more than enough space for backing up typical datasets; archiving photos, MP3s, graphics, and the like; and casual file swapping. For digital video editors, high-resolution audio editors, and local backups, the additional space—as well as speed—should come in handy.
Although TDK and Calimetrics do not expect DVD recording to fall out of fashion anytime soon, they expect to find a market between the high and low end. "This new technology is not a threat to DVD because of DVD's storage capacity, but it does offer a middle option between CD-R and DVD-R," says Bruce Youmans of TDK Electronics. "The ML format is a bridge to the era of inexpensive recordable DVD," says Kuni Matsui, president of TDK Electronics. "For the next several years, however, we see a tremendous demand in the market for a format that extends and enhances CD's storage, speed, and value. MultiLevel Recording technology can eventually migrate to the DVD platform, where it will offer similar gains in recording capacity and write speed."
One question is, for a market that has become quite comfortable with the CD-R/RW format and all of its benefits and drawbacks—especially the low cost—will longtime CD-R/RW be willing to adopt a new format? "Because of its cost advantages, we see this media as having a great potential for market adoption," says Burke. Speed is another selling point for the technology, and the 36X speed for ML recording is three times faster than current CD-R recording speeds, although the ML media is roughly three times larger than a CD-R disc.
The companies also plan to apply the technology to DVD media as well. "The MultiLayer media can extend with the CD family of technologies, as well as DVD. The first to market will be within the CD family because it is currently the most widely used and compatible optical disc technology currently in use," says Burke. In addition to TDK, supporters of Calimetrics' MultiLevel format include Mitsubishi Chemical Corporation and Plextor—a company that has also pledged its support for DVD+RW. "Our intent is to get the technology into an alliance, so that the technology can become widespread," says Youmans. According to both companies, product announcement will be made sometime around Q4 2001.
(TDK Electronics Corporation www.tdk.com. Calimetrics, Inc. www.calimetrics.com)