It may be an internal or external device. See DVD drives, DVD-R, DVD-RW, DVD+R and DVD+RW. (2) A stand-alone DVD player for TV viewing that also records DVDs on blank DVD-R discs or DVD+R discs.

Professional spectrometers cost many thousands of dollars, but you can build your own using a simple USB web cam, an old DVD-R, and a VHS cassette case. In this tutorial of Public Labs’ DIY ...