There are other solutions along these lines that are not written in OCaml. And generally the idea is to provide these other things as libraries, so you get a so

There are other solutions along these lines that are not written in OCaml. And generally the idea is to provide these other things as libraries, so you get a sockets library, and hardware support you can link in. eg the NetBSD rump kernel (http://rumpkenerl.org http://rumpkenerl.org) lets you reuse any netbsd driver, such as the ip stack or a filesystem, as a library.