[muricula]

The thing is there really isn't a production ready alternative. Rust in ring 0 isn't production ready -- a lot of language features needed to run in ring 0 are nightly only. There are no widely used microkernels. Ironically, of the widely used operating systems in the world, Windows does the best job of running drivers in userland.

[aphexairlines]

Microsoft had enough resources in the 90s and 2000s to get a safe language like ocaml running at least their network services.

[muricula]

OCaml in ring 0? Anything can be done if you try hard enough I guess.

MS had a research project to rewrite the NT kernel in a C# derived language at one point. It worked, but they decided not to go ahead with it.

[codedokode]

SMB server doesn't need to run at ring 0. It doesn't need direct access to hardware or physical memory. The most safe option would be to run a copy of SMB server under user's account (but it still would allow to encrypt all of the files).