Yo Si or Cy of Si` or Sue: [old Mel Blanc line from Radio]
If you are talking about the Sony Data discs for 8 track recording, which I use in my MD8, I've had very little problem with them.
Here is how YOU CAN HAVE A PROBLEM:[
If you are using a 4/8 track MD recorder and you cut a track or two tracks, like drums and chords, if you don't put those tracks into the CUE mode when you overdub the 3rd or 4th tracks, etc.,
YOU WILL LOSE DATA. CHECK THE MANUAL.
Also, since we live in a world filled with dust, sometimes I've gotten a "bad disc" message. The first time it happened was to a very new disc.
So, I gently used the vacuum cleaner on the disc and close to the disc housing. Things have been great ever since and I'm still using that disc.
Hope this helps you out.
Green Hornet