Discman was the product name given to Sony's first portable CD player, the D-5/D-50, which was the first on the market in 1984, and adopted for Sony's entire portable CD player line. In Japan, all Discman products are referred to as "CD Walkman" and the name was adopted worldwide in 2000 along with a redesigned "Walkman" logo.
Prior to release 
Prior to the development of the CD, cassette tapes were the dominant form of audio storage in regards to the then-fledgling portable audio industry. In 1979, Sony had introduced the Walkman in Japan. As Sony began to realize the potential of the CD, executives pushed for a means to give the CD player market momentum, moving it from audio enthusiasts to the mainstream.
Building on the design of the CDP-101, a CD player, Sony worked towards both improving the design of the player, reducing the power and number of parts needed while decreasing the overall size of the player, as well as reducing the cost of the player to a 50 000 - 60 000 yen range in what was called the "CD CD Project", which stood for Compact Disc Cost Down Project. With the ability to produce a CD player one-tenth the size of its first unit by August 1983, there became potential for a portable player.
The original goal was to create a player that was the equivalent size of four CD cases stacked on top of each other. A piece of wood 13.4 cm across and about 4 cm thick was shown to the staff to illustrate the physical dimensions for which they were aiming..
The D-50 (D-5 in some markets, including North America) was released in November 1984, two years after mass production of CDs began. The unit offered the same functionality as the full-size CDP-101 player, but came without a remote and the repeat functionality of the full-size unit. The D-50 retailed for only 49,800 yen ($350 in 1984), approximately half the cost price of the CDP-101. The unit successfully sparked public interest in CDs, boosting their popularity, and within a year and a half the D-50 became profitable.
Because of its portable nature and similarity to the Walkman, the nickname 'Discman' was given to the D-50. This name has been used to refer to any Sony portable CD player. However, Sony has since changed the name to CD Walkman, starting in the early 1990s.
The release of the D-50 sparked public interest in CDs as an audio format and in the audio industry in general. A portable CD market was created and the price of competing CD players from other manufacturers dropped. The CD industry experienced sudden growth with the number of CD titles available dramatically increasing.
- "Sony Celebrates Walkman 20th Anniversary". Sony Press Release. Retrieved 2009-05-04.
- Walkman Central - Reference site containing details and pictures of various Discman and Walkman models.