I work in digital mental health at the Division of Digital Psychiatry; perhaps some of our projects can serve as inspiration (https://digitalpsych.org/).
This has very little relevance to the topic at hand as these refer to electroencephalogram measurements taken through a skin (scalp) patch and conductive gel.
We had tremendous difficulty convincing Dr. Comer that using an experimental/nightly toolchain to compile an experimental compiler variant to use experimental libraries in an experimental language was worth it.
It took us quite some time to get everything up in a way that would work on most Purdue systems and our own personal ones and from there even translating the limited codebase we were using unsafe code blocks for nearly everything (and ASM blocks) and some internal code for multicore/ACPI-related things/Galileo boards we haven't made publicly available yet, AFAIK.
At the end of the day, Xinu was small enough and very concisely written and maintained for several decades that switching to a language like Rust wasn't warranted. Similar to sqlite, I suppose. You can email me at [email protected] if you'd like to know more details/talk to Dr. Comer about Xinu things.
Once upon a time, a colleague and myself attempted to rewrite Xinu in Rust to show Dr. Comer how cool it was. Rust did not work. It was not cool. Dr. Comer simply smiled a gentle "I told you so," as he had good reasons for sticking to C.
Not Linksys routers! They're typically Beaglebone/Galileo cards or something newer now. They actually run a special netboot-like version of Xinu that deploys your compiled xbin. (So it's like Xinu running Xinu...) There also was no such hypervisor, mostly TAs that responded to email complaints and took systems offline when hogged on accident.
What would you like to know? I did help set up a few things there. There's a special netboot-like version of Xinu deployed on the backend systems which are just Beagle/Galileo/whatever's been upgraded, and they deploy whatever Xinu image you've supplied. Students typically compile locally and submit the xbin (compiled kernel image) to a backend.