You would put these small square discs in a palm-sized thing They were big in the early 00's and they had songs by Britney Spears Insync the Backstreet Boys etc What are these called?

You would put these small square discs in a palm-sized thing They were big in the early 00's and they had songs by Britney Spears Insync the Backstreet Boys etc What are these called?
I think you're referring to minidiscs.... http://en.wikipedia.org/wiki/MiniDisc