Btw, if anyone is interested in learning how to write an OS, and interested in Rust, check out https://intermezzos.github.io/. It's a "learning OS" in Rust, with a companion book. Incomplete, but a good start.
Steve, thanks for all your work on this and with Rust. Your attitude toward teaching and your writing ability go a long way in encouraging people to learn and in having the lesson be worthwhile.