A Minidisc is a small, recordable disc, usually used for recording music.
The Benefits of Minidisc
The music is stored digitally1 so there's no hiss or crackle.
It has quick access times, just like a CD. If you want to get to track nine, you can, dead easily, dead quickly.
You can add titles to each track. So you know what song you're listening to.
You can shuffle tracks about. So if you thought that actually, the third song should come first, you can do that instantly.
You can delete tracks completely. So if you didn't like the third track, just a couple of buttons and it's gone.
It doesn't skip when bumped. While it's not infallible, most players store about five seconds of music in their memory, so they've five seconds after a big jolt to catch up again.
They're very little. So your minidisc player can be very little too.
The Drawbacks of Minidisc:
Not as many people have them instead of CD players and probably never will.
They're not much use for computers as only a few people make minidisc drives, and they only hold about 200Mb anyway.
They compress the music as they record it. You're unlikely to notice this initially. It's throwing away about 80% of the music information, so if you copy a minidisc and copy it again and again, you'll start noticing the effect.
Not many pre-recorded minidiscs are made. Most people buy CDs, and then copy them onto blank minidiscs so they can only get the tunes they want. This isn't as mad as it sounds, because your pristine and expensive CD is therefore always safe, and you can lose your minidisc whenever you like.
Alternatives to Minidisc
Cassettes are one alternative as the players are cheaper, but cassette tapes don't sound as good as minidiscs, and there's no quick way to skip tracks or edit them. A digital cassette system called DCC failed to take off.
Recordable CDs are another alternative and again, the players are cheaper, but music CDs aren't editable in the same way as minidiscs - once they're recorded, they stay recorded. Minidiscs are re-recordable over 1,000 times.
MP3 players are about the same price as Minidisc players, are smaller and won't skip at all. Music piracy can be a problem. Downloading MP3 audio from the Internet is easy and convenient.