>           st0: Error with sense data: Current st09:00: sense key
> Medium Error
>           Additional sense indicates Write error
>           mt: /dev/tape: Input/Output error
>
>       If I try: mt erase /dev/st0, it return me:
>
>            st0: Error with sense data: Current st09:00: sense key
> Medium Error
>            Additional sense indicates Write error
>            mt: /dev/tape: Input/Output error

but /dev/tape and /dev/st0 are not generally the same thing

what does an ls -l of /dev/tape and /dev/st0 (should be nst0) give you? are
they symlinked?