Damaged Tapes

[Ian G Batten]

I have a friend (really!) who has done a very careless thing.  He
inserted a QIC-11 tape which had some vital data on it which was write
enabled into a tape drive and wrote a few kilobytes over the beginning
of it.  Given that I have kernel and driver sources for V.3 machines and
various other equipment scattered about, can anyone suggest anything
which might drag some of the data off?  I've tried the obvious method of
reading the tape to the end of media and then trying again using a
non-rewinding open, but I simply get read failures.  I assume the
problem is that I have a partial block following the double tape mark.

ian