Compact Discs

Compact discs (CDs) are optical discs that store digital data. The data is digitally encoded on the disc as a series of microscopic indentations—called "pits"—on an otherwise polished surface. The disc is read by a laser beam, which is either absorbed in the pits or reflected off the non-indented areas, called "lands." After the music CD was introduced in 1982, it quickly surpassed records and cassette tapes as the music storage medium of choice. What album was the first to be released on CD? More...