The Eight Track tape recording system was popular from 1965 to the late 1970s. While today it has become an icon of obsolescence, it was a great commercial success and paved the way for all sorts of innovations in portable listening. The eight track tape consisted of an endless loop of standard 1/4-inch magnetic tape, housed in a plastic cartridge. On the tape were eight parallel soundtracks, corresponding to four stereo programs. For many people old enough to have owned an eight track system, it is a technology associated with the automobile and in-car listening. Ironically, however, it was first developed not by the auto industry, but by a leading aircraft manufacturer of the day: the Learjet Corporation.