In 1979, Sony made history by releasing the first Walkman.
The Walkman took a decade for sales to reach 50 million.
It was originally to be called the "Soundabout", "Pressman" or "Stowaway".
Sony listened to European kids who called the new gadget a Walkman.
The Walkman looks big and bulky to us now but in its day, it was considered the ultimate in personal sound devices.
Have you seen the old movies and television shows with people carrying those huge sound systems on their shoulders? They were called "Boom boxes".
They were what everyone had become accustomed to carrying around for portable sound.
The smaller devices did not have the quality or the loudness young people needed.
The Walkman was the answer for anyone who wanted quality sound without building up huge muscles from carrying around devices that weighed several kilograms.
One problem with the Walkman was that it did not handle a lot of movement.
You could not take it jogging or even walk fast while playing your music.
Dancing while listening was not an option, unless you were into slow dancing.
The Walkman was also limited to the number of songs you could play.
The first ones only held cassette tapes.
You could get one album onto a cassette tape.
The problem with the tapes was that they were forever breaking or unrolling inside the machine.
Later versions of the Walkman held CD's but they only held one CD.
You could carry around a pack of your favourite CD's and change them repeatedly.
They even had a range of CD holders that were good fun.
The iPod is so much better than the Walkman but we have to thank Sony for putting the industry onto the right track.