Sony's first Walkman that played CDs was launched in 1984 and was internally called the Discman. It was also known as the D-50 and D-5 in some markets. It was eventually renamed CD-Walkman in 1999.
The D-50 was the first portable CD player in the world and played a major role in popularizing compact discs. It cost about $350, which was only half the cost of manufacturing it, according to History of Things. Six C-size alkaline batteries provided the D-50 with up to five hours of battery life. In 1992, Sony invented the world's first Walkman that played MiniDiscs. The device featured playback, anti-skip technology, and the ability to record for up to 74 minutes.