after a nuclear war, the remaining people will probably not be able to spin up a modern operating system on their improvised chips. How do you build a simple, reliable, legacy-free OS from scratch? What ideas 💡 and techniques should be passed down to those people?

If we think hard enough about this, I think we’ll agree that closed-source systems are basically designed to be almost impossible for people outside the sponsoring organization to reproduce (for an example, consider [ReactOS](https://reactos.org/), which launched as [a project to produce a system compatible with Windows 95](https://reactos.org/wiki/FreeWin95) and [then changed to focus on Windows NT](https://reactos.org/wiki/ReactOS/History), and after more than 25 years, is still not capable of being a daily use system.

But we may also determine that most open-source systems are likewise not designed in such a way that reconstruction is viable. The Linux kernel is *huge* these days.

Additionally, in my opinion, they’d probably want to use programming languages designed for readability, ease of learning, and error-reduction first (that is, more like #COBOL than #C, more like #Java than #CPlusPlus, more like !Smalltalk and #Lisp / #Scheme than #Perl / #Raku and #JavaScript) and then performance and low-level access.

I think it is a mistake to assume that one could start with a modern version of #gcc or #llvm or #msvc … because it is not a given that the software itself and someone who knew how to use it (and update, modify, and adapt it) would still exist.