I guess it's a [mis]feature, since 5.00 worked, but can hardly imagine anybody could need it.

======= Prelude> h<-IO.openFile "/dev/zero" IO.ReadMode *** Exception: unsupported operation Action: openFile Reason: unknown file type File: /dev/rtf0 Prelude> Leaving GHCi. max@max$cat /dev/zero <C-C> =======

Thanks; will be fixed in 5.02.2. Cheers, Simon