Cornell has a 2000 line educational operating system called EGOS (egos-2000 on GitHub) designed by professor Robert van Renesse. It has memory paging, virtual address translation, interrupt handling, process scheduling, system calls, and can run on QEMU or RISC-V.
Sometimes ultra-minimal is really too simple, and it lacks the userland and kernel bits that can be tweaked and built upon for course assignments that resemble things in the rest of the POSIX world.
MINIX 2.0 is mostly published in the text of Operating Systems: Design and Implementation (1997) by Tanenbaum. It's a superior OS for teaching UNIX philosophy and OS concepts rather than starting with a contrived OS that has no relevance to anything. It runs on vintage x86 machines (QEMU/etc.) no problem. About the first hack I added to it was upping the keyboard repeat rate to maximum and delay to minimum.
Some schools have drifted away by using more complicated OSes like FreeBSD as their generic UNIX and OS teaching platform, but this throws out the simplicity of MINIX <3.0. The MINIX kernel and basic userland fit in very little code, it can almost all fit in your head, there's a book that goes into detail about most of the important concepts, and it can be rebuilt on modern machines in seconds.
Previously, 2023, 19 comments: https://news.ycombinator.com/item?id=35982037
There are updates in the last several months, so it looks like the project is still active.
Cornell has a 2000 line educational operating system called EGOS (egos-2000 on GitHub) designed by professor Robert van Renesse. It has memory paging, virtual address translation, interrupt handling, process scheduling, system calls, and can run on QEMU or RISC-V.
Sometimes ultra-minimal is really too simple, and it lacks the userland and kernel bits that can be tweaked and built upon for course assignments that resemble things in the rest of the POSIX world.
MINIX 2.0 is mostly published in the text of Operating Systems: Design and Implementation (1997) by Tanenbaum. It's a superior OS for teaching UNIX philosophy and OS concepts rather than starting with a contrived OS that has no relevance to anything. It runs on vintage x86 machines (QEMU/etc.) no problem. About the first hack I added to it was upping the keyboard repeat rate to maximum and delay to minimum.
Some schools have drifted away by using more complicated OSes like FreeBSD as their generic UNIX and OS teaching platform, but this throws out the simplicity of MINIX <3.0. The MINIX kernel and basic userland fit in very little code, it can almost all fit in your head, there's a book that goes into detail about most of the important concepts, and it can be rebuilt on modern machines in seconds.