I tried doing things by hand,
running maketape and then "cat"ing the file it created along with all
the other files "dd"ed by the script into a single file.
You need to put file marks between everything logically 'dd'-ed
In the .tap format, file marks are four bytes of 0.
End of tape should have two sets of file marks (eight bytes of 0)
FWIW, I sent warren a .tap image of Ultrix 2.0. Never heard anything from
him about it.