[OneWingedShark]

> I imagine COBOL is similarly stable but I have no experience there.

I haven't programmed in COBOL, but it is quite stable. One of the really nice things in COBOL is the "Environment Division", which has a Configuration Section, which provides information about the system on which the program is written and executed. It consists of two paragraphs − – Source computer: System used to compile the program. – Object computer: System used to execute the program.

Another remarkably stable language is Ada, I have used it to compile non-trivial programs from 30+ years ago, on a different architecture than it was originally written for (granted, without system dependency) using a modern compiler without anything more than (1) renaming identifiers which had been made keywords, (2) splitting files due to GNAT's implementation limitation regarding compilation-units.