2.4.3 Is CD-R compatible with DVD-ROM?
Description
This article is from the DVD Formats FAQ, by jtfrog@usa.net (Jim Taylor) with numerous contributions by others.
2.4.3 Is CD-R compatible with DVD-ROM?
Sometimes. The problem is that CD-Rs (Orange Book Part II) are "invisible"
to DVD laser wavelength because the dye used in CD-Rs doesn't reflect the
beam. Some first-generation DVD-ROM drives and many DVD players can't read
CD-Rs. The formulation of dye used by different CD-R manufacturers also
affects readability. The common solution is to use two lasers at different
wavelengths: one for reading DVDs and the other for reading CDs and CD-Rs.
Variations on the theme include Sony's "dual discrete optical pickup" with
switchable pickup assemblies with separate optics, Sony's dual-wavelength
laser (to be initially deployed on Playstation 2), Samsung's "annular
masked objective lens" with a shared optical path, Toshiba's similar shared
optical path using an objective lens masked with a coating that's
transparent only to 650-nm light, Hitachi's switchable objective lens
assembly, and Matsushita's holographic dual-focus lens. The MultiRead logo
guarantees compatibility with CD-R and CD-RW media, but unfortunately, few
manufacturers are using it.
An effort to develop CD-R "Type II" media compatible with both CD and DVD
wavelengths was abandoned.
DVD-ROM drives can't record on any media. There are a few combination
DVD-ROM/CD-RW drives. Current writable DVD drives (see 4.3) can't record on
CD-R or CD-RW, although future versions may be able to.
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