Hmmm, that link doesn't point to the right page for me. Perhaps because we're using different number of posts per page?

Here's a link to the post in the thread and a link to the single post.

I don't have any inside knowledge of ScanDisc - only what I have learned from observations. Erik Deppe would be the one to ask about inside knowledge.

It's my observation that all drives can report red (bad) sectors in ScanDisc for sectors that fail to read. A few drives report all other sectors yellow (damaged) when connected externally. Most drives can report sectors as green (good) but not all drives will report yellow (damaged) sectors.

So in other words, some drives will only report green (good) and red (bad) sectors but not yellow (damaged) sectors. In my opinion such drives are not suited for ScanDisc Read Testing.

The behaviour might be different depending on whether a DVD, a data CD or an Audio CD is scanned. (This is my speculation based on the difference in error correction between these media types).

It's not completely clear to me whether the damaged sectors are a result of the software having to re-read, the result of the drive reporting that it had to re-read, or something else such as e.g. C2 info. You'd have to have internal knowledge of the program to know that for sure.