FORTRAN 77 added if/else branches, clearer loops, and text handling — making large scientific programs easier to read and maintain. It became the baseline for weather models, engineering simulation, and supercomputing for decades. Much legacy scientific code still targets this version.

FORTRAN 77 is what most people mean by 'classic FortranFormula Translation — one of the first high-level languages, dominant in science and engineering.' — the version that ran on supercomputers for a generation.

It brought readable program structure to scientific computing without breaking the formula-first style researchers already relied on.