Fiwix: Small Unix-Like Kernel

Interesting. While I do appreciate that it runs on i386, I have to question its being aimed at students - or at least students of anything other than the history of computing. i386 implies BIOS, AFAIK, and requires pre-x86_64 assembler, which is only partially transferable to modern CPUs.

Oh, for sure, one would learn an awful lot working with those technologies, but as soon as one wished to work on more modern systems, one would have to forgot all of the former and all the ugly of the latter.

This isn't really a criticism, more an expression of puzzlement. Normally, I'm a pretty good contrarian, but I don't get it.

True, there was this Finn who did this some time ago and it worked out pretty well, but I still don't get why anyone would start with i386 and BIOS.

What's the difference to e.g. xv6?

There are already so many Unix like operating systems of all sizes written in C (e.g. Minix, xv6, BSD, Darwin, Hurd, Lemon, MentOS, SanOS). If I were to go to such an effort, I would try another language, or even my own (like e.g. Bunnix written in Hare). It is meanwhile more than clear that it can be done in C. But C is not really a good programming language (weird syntax, incomplete type checking, many specification gaps, etc.), so it would actually be more interesting to explore the suitability of other languages for such a task.