[tjalfi]

These days, we have many better options, but back in the day, Fortran was also used for compilers (e.g., IBM's Fortran H), operating systems (such as PRIMOS[0] and LTSS[1]), symbolic computation (e.g., early Prolog implementations), and real-time control systems[2].

[0] https://en.wikipedia.org/wiki/PRIMOS

[1] https://en.wikipedia.org/wiki/Livermore_Time_Sharing_System

[2] https://webhome.weizmann.ac.il/home/fhlevins/RTF/RTF-TOC.htm...