Archaic to modern 1: basic tools & issues

Including the new Fortran 2003, there are three revisions of the Fortran standard beyond the venerable, quarter-century-old Fortran 77. While the newer revisions, Fortran 90, 95 and 2003, have standardized more features, they are (very nearly) upwards compatible with Fortran 77. In fact, many of the new features are standardisation of extensions implemented by Fortran 77 compilers, albeit each with its own spelling. Still, the introduction of modern Free Format in place of the card-image-based Fixed Format, and the overall amount of new features (many first appearing in the Fortran 90 standard), means that some applications programmers consider modern (90, 95, 2003) Fortran to be a different language than archaic (66, 77) Fortran.