Formerly I used a removable Hard-Drive for all my backup's but now I've got a CD-RW drive I want to use CD-RW's for my back-ups.

One thing that bothers me is that I know that given time and enough erasures that the media may become unreliable. But I don't have any way to test the current state of the media so I’m assuming that the first I’ll know about this is when I can’t read a (possibly irreplaceable) file .

Does anyone know of any good software to test CD-R and CD-RW media?