I apologize if this is an obvious question, but I'm going to ask it anyways... I'm trying to understand, what exactly happens in a fastscan operation? I've read that it basically does that same thing as a scan, but instead operates on the incorrect files generated from a full scan. But it seems to be doing more than just that. For instance, take a set that has scanned cleanly and is perfect. For this set the list of incorrect files is presumably empty. Now, if I mess with any of the files in the set (rename it, duplicate it, etc) and run a fastscan, the fastscan detects it and corrects it!

Now of course I'm not complaining- it's great that it can fix those problems. I'm just trying to understand, when exactly to I ever need to run a full scan? Is it only when scanning for the first time with a datfile, and thereafter I should always use a fastscan? Or is there something else that I'm missing. I'm tempted to just always run fastscans because they are so fast, but I want to make sure that the fastscan isn't missing some critical error that would be caught with a full scan. Do those conditions exist?

Any advice would be much appreciated.

(On a side note, this is an excellent program- I'm always surprised at how fast it runs. You must be using some very fast hashing functions and a lot of disk caching or something like that? If you want to shed some light on how you perform these operations on so many files so quickly, I'd love to know...)