The Cavern project aims to build an operating system, mostly for entertainment. The name "Cavern" is inspired by hobby tunneling, in which people dig tunnels for no reason but the pure enjoyment of digging. Like digging a tunnel, building an OS is hard work with lots of stressful decisions and trade-offs, but with the right mindset it can be enjoyable for the committed. This project builds on my previous efforts in the k project.
Cavern follows a microkernel architecture, using message passing and kernel-managed direct memory transfers to communicate between processes. Check out the specification for the system and for the kernel for more details.
Here's what it currently looks like to boot (slowed down significantly for readability, click for original):