Fortran was ad still is a Lingua Franca un the sciences and engineerig community, INTEL in the 1970's distributed PL/M, a downsized PL/I ( it's available today ) as two pass PL/M compiler, for its micros, written in FORTRAN 77 : I mention PL/M, because the first microcomputer operating system CP/M was written in PL/M
you coud use it in most minis and mainfames of the time
carlos feldman