🚀 go-pugleaf

I just got a clobbered disk -- the full-disk copy won't, and copying
file-by-file won't copy some of the files.  (Fortunately, this happened
about 3 hours after I backed up the active files, so I'm not in
serious trouble).  But:

1) How can I find out if this is a hardware (corrupted media) or
   software (TOS scribbled garbage)?

2) If some TOS-internal checksum was clobbered, (assuming there is
   one), are there any tools -- and accompanying documentation --
   that can help me recover the two missing files?

3) If it's a hardware failure, is there a raw copy utility that
   can grab what is available (turning it into a software problem
   that can be fixed by hand-editing a track)?

While I'd prefer public-domain software with sources and documentation,
pointers to well-written commercial packages would also be appreciated.

Thanks.

Martin Minow
decvax!minow