Optical Disc

An optical disc is a data storage media, usually produced from combined layers of polycarbonate substrate(a type of plastic); organic polymer dye; a reflective layer often made from a gold, silver, or aluminum alloy; and an ultraviolet-cured lacquer.

Formats of optical discs include CD(R, -RW), (HD)DVD(-R, +RW, -RW), and BluRay. Each format has different maximum size capabilities and are made from slightly varying materials. More importantly, not all formats will read in every drive. A CD-ROM drive can only read CDs, but not DVDs; a DVD-ROM drive can read all kinds of CDs and DVDs.