Increased availability and declining prices are tempting PC users to consider replacing their CD-R/RW drives with DVD recorders. Sales of DVD equipment have now surpassed the sales of VCRs and CD drives and recorders in PCs.

However, the ubiquity of the CD is both a hindrance and an advantage to the acceptance of DVD as the next universal technology. Because DVD-ROM drives can read CD-ROMs, there is a compatible forward migration path and some manufacturers plan to cease CD-ROM drive production after a few years in favor of DVD-ROM drives. But, buyers beware. Currently the plethora of incompatible DVD recording formats hinders ready acceptance by PC users whose standard has been the universally compatible CD format. Secondary problems that DVD acceptance faces, such as higher media costs, are offset by the increased storage capacity available with DVD technology. But the format wars must be successfully resolved for DVD to achieve the universal acceptance that CD enjoys.

Now a group including HP, Philips Electronics, Sony, Dell, Ricoh, Thomson, Yamaha, and Mitsubishi Chemical/Verbatim are developing the next generation of optical storage technologies with the DVD+RW format. These discs can be read and played on most existing and future DVD-video players and DVD-ROM drives, and more than 25 additional companies have formally pledged support for DVD+R and DVD+RW technology. The apparent acceptance of this technology as a de facto standard by manufacturers may well serve to resolve the early format wars.

DVD+RW rewritable discs are a large and cost-effective storage solution. With a capacity of up to 4.7GB, these discs can store hours of video or multimedia presentations, and thousands of photos and other files. The capacity of one DVD+RW rewritable disc equals seven CDs, 47 100MB ZIP disks or 3,263 floppy disks.

Several new drives will be available soon that support the newer DVD+RW format, among them second and third generation units from Philips, Sony, and HP.

Philips DVDRW228

The $449 Philips DVDRW228 (www.philipsusa.com) is fast, easy to set up (even for a novice), and offers Seamless Link technology's buffer underrun protection. Compatible with Windows 98, NT 4.0, 2000, Me, and XP, the bundled software is geared more toward multimedia tasks than data processing. It includes Sonic Solution's MyDVD 3.5 (a simple DVD-authoring program), as well as Ahead Software's easy Nero Burning ROM 5.5 (which is good for both DVD- and CD-writing tasks), Pinnacle Systems' Pinnacle Studio software (a sophisticated movie-editing program), and CyberLink PowerDVD decoder software (for watching DVD movies on your computer).

Philips DVDRW228

The Philips DVDRW228 reads all common CD formats and can also write to inexpensive CD-Rs and CD-RWs.

Last year, Sony became the first company to deliver a multiformat drive with support for DVD+RW, DVD+R, DVD-RW, and DVD-R. Now the new internal DRU-500AX and the external DRX-500ULX drives will be available this month for less than $350 and $430, respectively. (www.storagebysony.com/news/pressengine.asp?id=50) While this drive supports all four popular formats, it is only PC-compatible and has no Macintosh support. While the units ship with the ability to write DVD+R/DVD+RW discs at the industry-standard 2.4X, you can download a free upgrade from Sony's Web site that will enable the drive to write DVD+R media at 4X. An 8MB buffer memory and Power-Burn technology prevents buffer underruns.

The DRU-500A also comes with Veritas RecordNow software for mastering writable and rewritable DVDs and CDs; Veritas Simple Backup for backing up data; Sonic MyDVD, which turns your home movies into video DVDs; ArcSoft ShowBiz for video editing; MusicMatch Jukebox, which lets you play, record, and organize your music; and CyberLink PowerDVD 4.0 for DVD-movie playback.

Pioneer’s DVR-A04

Pioneer's DVR-A04 drive writes and reads DVD-RW, DVD-R, CD-R and CD-RW media, and also reads CD-ROM and DVD-ROM discs and supports both PC and Power Mac G4. (www.pioneerelectronics.com) Unfortunately, upcoming DVD+RW drives from other manufacturers beat the DVR-A04 on speed and compatibility.

Last month HP announced the DVD 300i internal DVD writer ($299) and the DVD 300e external DVD writer ($399), which includes both FireWire and USB 2.0 connections. The drives can write to high-capacity 4.7GB DVD+Rs at speeds up to 4X. (www.hp.com/hpinfo/newsroom/press/2003/030107a.html)

In 2001, the DVD Forum (www.dvdforum.org) approved the first DVD Multi specification - covering all currently developed formats approved by the Forum. Hitachi and Panasonic were first off the mark to announce DVD Multi-compliant drives, providing read/write support for all DVD Forum recordable DVD specifications - DVD-RAM, DVD-R and DVD-RW - as well as read/write support for CD-R and CD-RW media. Importantly, however, formats created outside the DVD Forum - notably the DVD+R and DVD+RW formats supported by Dell Computer, Hewlett-Packard and Philips and other members of the DVD+RW Alliance - are not covered by the DVD Multi specifications.

Like CDs, DVDs store data in microscopic grooves running in a spiral around the disc. All DVD drive types use laser beams to scan these grooves. Minuscule reflective bumps (called lands) and nonreflective holes (called pits) aligned along the grooves represent the zeros and ones of digital information.

But that's where the similarities end. DVDs use smaller tracks (0.74 microns wide, compared to 1.6 microns on CDs) as well as new modulation and error correction methods. These technologies allow them to store data seven times as large as that of a CD.

As a result, some first-generation DVD-ROM drives and many DVD players can't read CD-Rs. Most CD-Rs are "invisible" to DVD laser wavelength because the dye used to make the blank CD-R doesn't reflect the beam. The formulation of dye used by different CD-R manufacturers also affects readability. That is, some brands of CD-R discs have better reflectivity at DVD laser wavelength, but even those don't reliably work in all players. The common solution is for the DVD player or drive to use two lasers at different wavelengths, one for reading DVDs and the other for reading CDs and CD-Rs. A player bearing the MultiRead logo guarantees compatibility with CD-R and CD-RW media, but unfortunately, few manufacturers use it. So if you want a DVD player that can read CD-R discs, look for a "dual laser" or "dual optics" feature.