If you're starting with MirageOS, then obviously makes sense to just run MirageOS a bare-metal hypervisor. But if you're starting with the assumption that you will be running in a JS VM, then you have two options: build a unikernel in JS, or compile one to JS. The later option (MirageOS compiled to JS) also happens to leave open the possibility of easily being ran on a bare metal hypervisor with the unikernel implementation itself also running on bare metal (without a language level virtual machine) - because OCaml executes without a language level virtual machine (it's more like C++ in that sense).
> The obvious benefit of a JS VM unikernel is that you get to write your application in JavaScript...
What are some reasons why that would be a good thing in the case of unikernels? (I'm genuinely asking) The type system and invariants that it enforces are one of the things that makes OCaml based unikernels such a compelling idea to me. JavaScript, although I obviously find it useful for many things, doesn't seem to have as much appeal in this case.
Relevant to security: See MirageOS's Bitcoin Pinata project: http://amirchaudhry.com/bitcoin-pinata/
Edit: Again, it's still cool to see this project, and it's a great way to get more people experimenting with the idea of unikernels.
