I wondered about an adjacent topic recently ("what IS the kernel actually") and found out that a great way to understand it, would be to start with the boot process. Once I felt less lost, I tried to capture my learnings [1]
The text is not edited yet, but as I had the benefit of learning about it with fresh eyes, it should be very approachable (and hopefully accurate enough)
> It’s firmware time. Your machine has a motherboard, there is a chip on it which has had BIOS (Basic Input/Output System) flashed on it.
I wonder if it's worth it to call out the "processor microcode" firmware? Any cool startup things happen at that low level as well?
Way out of my depth! However, the stuff I saw the folks from Oxide [1] talk about comes to mind. Hardware stuff with Rust. If you want to look at a specific project, Hubris [2] is a kernel for "deeply-embedded" systems.
[1] https://oxide.computer/blog/building-big-systems-with-remote...