Sony Walkman's 30th anniversary

A Sony employee displays the first model of Sony's stereo cassette player "Walkman TPS-L2" (left) and the second model "WM-2" at the company's museum in Tokyo.

Sony has sold 385 million Walkman machines worldwide in 30 years as it evolved from playing cassettes to compact disks then minidisks -- a smaller version of the CD -- and finally digital files.

A Sony employee displays the first model of Sony's stereo cassette player 'Walkman TPS-L2' (left) and the second model 'WM-2' at the company's museum in Tokyo. Sony has sold 385 million Walkman machines worldwide in 30 years as it evolved from playing cassettes to compact disks then minidisks -- a smaller version of the CD -- and finally digital files.