Japan's electronics giant Sony employee

Japan's electronics giant Sony employee dispays the first model of Sony's stereo cassete player "Walkman TPS-L2" at the company's museum in Tokyo on July 1, 2009. Thirty years ago Sony launched the Walkman, a gadget which revolutionised the way people around the world listened to music but has since been overtaken by an icon of the digital age. Sony sold 30,000 Walkmans in the first two months after its launch, and 50 million within a decade. AFP PHOTO / Yoshikazu TSUNO (Photo credit should read YOSHIKAZU TSUNO/AFP via Getty Images)