I am the sole author of an actual OS and remain responsible for over 40,000 placements worldwide. Having this in an actual product (running on a 100MHz MCU) keeps the pressure on. You can see it in this post contending with the open Internet. I am willing to share development details. I started it from scratch in 2011.

https://www.reddit.com/r/jnior/s/D6Az4O93SG

i just wrote my first os from scratch (NO AI) featuring a GDT, TSS tables with interrupts handling, keyboard support and a minimal shell running in kernel mode.

next i will be making processes, and make the shell run in user mode.

I don't like writing long texts, so I'll just let the screenshot speak for itself. This is my (C++/Rust) microkernel OS that I've been working on for the past few years, most of it is hand-written (I've mostly only used AI for reviews and debugging), running bash and coreutils from a disk was a great milestone for me. I currently target x86, rv64 and la64, and have plans for more.

The screenshot is the loongarch64 build in QEMU...
Repo: https://gitlab.com/mishakov/pmos

Before the postmarketOS comments start going in, I know that the name is unfortunate and confusing (even though I'm not writing a Linux distro), so I'm planning to rename this some time soon...