Is anyone aware of why the FORTRAN exe file contains a line at the top that says == This program cannot run in DOS MODE?
It is 25 years since people used DOS?
Answered my own question a few minutes later -- the DOS stub is at the start of all EXE programs and gives an error message if executed
It is a consequence of backward compatibility. DOS and extended applications had to cohabit for a while so this stub was mandatory to avoid launching a mismatched application.
There are many other things like that under Windows and even I think Linux.