Xous is a message-passing microkernel implemented in pure Rust, targeting secure embedded applications. This talk covers three novel aspects of the OS: hardware MMU support (and why we had to make our own chip to get this feature), how and why we implemented the Rust standard library in Rust (instead of calling the C standard library, like most other Rust platforms), and how we combine the power of Rust semantics with virtual memory to create safe yet efficient asynchronous messaging primitives. We conclude with a short demo of the OS running on a new chip, the "Baochip-1x", which is an affordable, mostly-open RTL SoC built in 22nm TSMC, configured expressly for running Xous.