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 -- the iPod.

The July 1, 1979 rollout of the portable cassette player helped transform the Japanese company into a global electronics powerhouse.

Sony sold 30,000 Walkmans in the first two months after its launch, and 50 million within a decade.

Three decades on, however, Sony is struggling against rivals such as Apple, which has enjoyed immense success with its iPod music player.

Times have changed since Sony engineer Nobutoshi Kihara sketched out designs for the Walkman by hand.

"Back in my days, we had to draw product designs on paper," Kihara told AFP in an interview in 2006 after his retirement.

"I would close my eyes and imagine our products. I would imagine joggers with Walkmans to see how the hinges should move or how the products fit into the lives of the users."

Sony co-founder Masaru Ibuka came up with the idea for the gadget on one of his overseas trips, during which he used to listen to music on existing tape recorders that were too heavy to be considered truly portable.