Nero CD Speed questions

I started using that tool but I have hard time interpreting the results. Is there a help for CDSpeed?

If not,

  1. What does damaged mean in ScanDisc (I had couple on my recent scan)

2 What is difference between ScanDisc and CD quality check

a damaged sector is when the reader has to read that passage multiple times before it can know the correct values of it (error correction this is)
a unreadable sector is when 2 much is damaged to be able to get all data back

and think the cd check thingie is for audio cds