> Fiwix is an operating system kernel written from scratch, based on the UNIX architecture and fully focused on being POSIX compatible. It is designed and developed mainly as a hobby OS and, since it serves also for educational purposes, the kernel code is kept as simple as possible for the benefit of students and OS enthusiasts. It is small in size (less than 50K lines of code), runs on the i386 hardware platform and is compatible with a good base of existing GNU applications.
https://www.fiwix.org/
> Fiwix is an operating system kernel written from scratch, based on the UNIX architecture and fully focused on being POSIX compatible. It is designed and developed mainly as a hobby OS and, since it serves also for educational purposes, the kernel code is kept as simple as possible for the benefit of students and OS enthusiasts. It is small in size (less than 50K lines of code), runs on the i386 hardware platform and is compatible with a good base of existing GNU applications.