

Over the past 20 years, tiny plastic discs have completely altered the way we store, distribute, and access music, movies, and information. These discs rely on technology that was first introduced in the early 70s–digital light. Vinyl records used mechanical grooves to store analog sounds, based on technology originally developed by Thomas Edison in 1877 (actually, that’s when he invented his first cylindrical recorder. It was 1912 when he invented the use of plastic discs for sound recordings). Audiotapes use magnetic fields to record analog information. Computer floppy and hard disks also use magnetic media, but they store data as a sequence of on and off fields, creating binary digital data.

But optical discs use light–not just ordinary light, but laser light. Lasers were invented in the early 1960s and made it possible to project a beam of coherent light of a single color that could be precisely focused without scattering. Later, tiny, solid state, semiconductor lasers were created, making it possible to manufacture small, inexpensive optical storage devices. Coupled with the computer technology, these developments set the table for a revolution in data storage.