Re: formally proven OS
It has been done, but an operating system is kinda useless without apps. I’d love to see something like that, but I suspect you’ll only ever see it as a niche product. ATM machines would be an excellent application.
I fear you might be right about niche usage; but I think that it would give a major leg-up to a consumer product. I mean imagine the marketing saying it's impossible to crash
and being right; and from a security standpoint it offers some amazing assurances (ref: the Ironsides DNS, No Single-Packet Denial of Service or Remote Code Execution Vulnerabilities).