I've thought about doing something like this but I am only very recently getting into low-level OS stuff.
I can't remember who said this, but they called "Erlang an operating system for your code", and I think that's fairly accurate. When I build an Erlang app, I don't build it the same way as I would with Rust; I have a lot of independent gen_servers that do operate independent from each other.
The Erlang VM is (roughly) preemptive multitasking, and even each process has its own GC, so it does feel like it could be a natural fit for its own operating system without having to live on top of Linux.
You know, I read those slides when they were new, and I apparently just completely forgot about it.
Not that it's not interesting, just that my brain is dumb sometimes.
Unfortunately, the hydros project website is gone. I'm not sure if it moved somewhere.
> browser-based demo
Wait, so is the browser running a JavaScript build of Qemu? /
I don't think v86 [1] is based on qemu, but it's a javascript (well javascript + rust->wasm) virtual PC. Not my project, it's super lovely for hobby os demos though. (And they've taken a couple of my PRs!)
[1] https://copy.sh/v86/ https://github.com/copy/v86
Is the OS implemented from scratch, or is it a stripped down version of some existing OS?
The kernel is pretty much from scratch. It provides a FreeBSD compatible syscall interface for the syscalls that BEAM calls, as well as the FreeBSD runtime loader. I do make healthy use of FreeBSD libraries to provide the OS, you can get an idea of what I pull from the file names in the Makefile [1]. Building an OS is a lot, so I tried to stick to the parts I find fun and interesting. Things like a NIC driver in Erlang [2] (with NIFs to copy to/from device memory). But process / thread creation is original, memory management is original (not necessarily good), time keeping is original, etc. I used existing code and interfaces so I didn't have to write a bootloader, memcpy, and lots of other stuff.
[1] https://github.com/russor/crazierl/blob/main/Makefile#L23
[2] https://github.com/russor/crazierl/blob/main/src/rtl_8168.er...