Oh god. Reminds me of simulated processor pipeline stages (VHDL, etc.), which tend of have a huge amount of state.

I'm no Fortran expert. Were there no composite types (i.e., structures or tuples) at the time or other reasons to do that (i.e., code testing tools)?

Edit: Last q: Yes, as a vendor extension

https://gcc.gnu.org/onlinedocs/gfortran/STRUCTURE-and-RECORD...