No. Shred will "work" - as in, compile, run, and have the expected logical effects of ultimately removing the file from the directory index - on any filesystem backed by any block device. The problem is that overwriting any part of a file is not guaranteed to actually erase the overwritten data. Actually, it never has been; shred is kind of a hack that assumes an overwriting file system driver and a block device dumb enough to not remap sectors writing to media that's intrinsically erasable. e.g. try running shred on a mounted CD-R and see how far that gets you.