A 1/8" inch, analog audio tape format that has been widely used for music distribution and home recording. Although the same size housing is used, the tape thickness and length determine the recording time. Cassettes holding from 15 minutes to 60 minutes per side have been manufactured.

Introduced by Philips in 1965, the "compact audio cassette" offered an alternative to the vinyl record player. Not only was it battery operated and portable, it was recordable, and the format became the standard among teenagers for taping concerts. As soon as commercial recordings on cassette began to proliferate, it became the standard for personal music playback in vehicles.

Enter the Walkman
In 1979, Sony introduced the Walkman, a small, lightweight and belt-worn audio cassette player that let a person comfortably listen to music via headphones while strolling. The progenitor of the digital music player, the tape-based Walkman was extremely popular during the 1980s. It evolved into a portable CD player by the end of the decade. See Stereobelt.

Digital Recording
In the late 1970s and early 1980s, many of the first personal computers allowed audio cassette recorders to function as digital storage. Never widely used, their transfer rates were slow, and the floppy disk was always preferred. See cassette.