My drives at home have problems with 2GB so it doesn't look like I'll be needing NTFS anytime soon. So far, I haven't had any files larger than 2GB, let alone 4GB. Or have I? I'm now thinking of using another application like DiffMerge (from SourceGear, I believe a reasonably trusted source) to pick up future updates. So, it does appear that I have backed up the master directory I wanted. I'll use DiffMerge to compare the two directories to see if they correspond (at least the main ones). Also, I notice that when I copy one file to another destination, additional bytes are added to the file. The problem is that I chuck so many things into the drive that there must be loads of files I don't really need but cannot be bothered to check and delete. As long as the media and document files are OK, I don't mind that some stray files and links that I don't use are broken along the way. When I compared the two directories, they're almost the same (356.25 GB in the original and 365.31 in the destination). I tried CCC but it gave me an error message (which I forgot to copy down before closing - it didn't seem important, about some exe file which I am not interested in). I found out that Time Machine does the same backup on both external drives (I only want the media and document folders in the second drive but complete backup on the first). Thank you for the most useful reply so far.

Synkron backup software