[londons_explore]

All the more reason to rewrite it... You don't want some mistake in 30 year old COBOL code to be making your 2023 experiment to have wrong results.

[gmueckl]

That's the complete opposite of what is actually the case: some of that really old code in these programs is battle-tested and verified. Any rewrite of such parts would just destroy that work for no good reason.

[_a_a_a_]

Why don't YOU take some old code and rewrite it. I tried it for some 30+ year old HPC code and it was a grim experience and I failed hard. So why not keep your lazy, fatuous suggestions to yourself.

[mlyle]

The whole point is in these older numerical codes is that they're proven and there's a long history of results to compare against.

[dpe82]

*FORTRAN.