Sony Minidisc
1992-2001
This digital audio format worked just like a CD, only it was smaller and more convenient. Although Sony anticipated great success with the MiniDisc, record companies didn’t adopt it as expected, which led to a lack of available music. The MiniDisc also competed with the cheaper, recordable CD. It all ended in the late 1990s when the superior MP3 players killed the struggling MiniDisc.
Additional info:
TheGuardian - MiniDisc, the forgotten format
t3.com - MiniDisc: The format that failed