Reverse Duplicate File Finder

[mam3]

Hi,

I found FFS after doing a google search for a feature I'd like to see. But maybe FFS does this already:
I need a program that will take a list of files on DRIVE A, and search for them on DRIVE B and tell me which files are not on drive B.

I got as far with FFS as the point where it compares entire directory structures first then looks for duplicate files in a matching directory. I simply want it to ignore directories altogether and look for the same files regardless of which directories they are in on the source and target drives.

Is this possible with FFS? How about a different software?

Side note, I kind of tried this by printing out the list of files on both drives using the command prompt and I could have done this in excel, except its millions of rows and crashes my machine.

[therube]

FFS will take the the directory structures into consideration.
It does not work in a "flat" mode.

Maybe something here, links from there, will give you something to chew on, Ignore duplicates (i.e., unique)?