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Comment by fbn79 | Hacker News Reader

I never used Erlang, and I'm a functional programming fan. But languages based on heavy VM that abstract OS away always make me doubt that's the right direction.

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That's not a crazy instinct, and maybe if OSs were better you would even be right, but there's not really another way to get a skrillion communicating processes that can all crash/fail independently. Without a dedicated VM, all the other approaches are either less safe or too inefficient.

I consider BEAM an indication of a direction that OSs could and maybe should move. It's even possible to run BEAM on bare metal, (almost?) entirely in place of the normal OS.

> It's even possible to run BEAM on bare metal, (almost?) entirely in place of the normal OS.

How? With a unikernel?

i would think so, no other option afaik.

I've built a hobby OS around BEAM... BEAM doesn't require a whole lot from the OS, I built a minimal kernel that runs a single process, which you could consider a unikernel or at least very close. I had originally wanted BEAM in ring 0, but I had a lot of trouble getting started. This way, I can just use a pre-compiled BEAM for FreeBSD and don't have to fight with weird compilation options. Anyway, with x86-32 at least, I can give my Ring 3 process access to all the ioports and let it request a mmap of any address, so the only drivers I need in the kernel are IRQ controllers, timers, and pre-beam console. Once beam is up, console i/o and networking is managed from erlang code (with a couple nifs)

Using GRiSP Metal, not exactly without an OS, but using a real time OS designed for embedded devices.

https://www.grisp.org/software

It's been a while, but I believe so. I think I'm remembering the "Erlang on Xen" project, which seems to be defunct now.

What makes you think the BEAM VM is "heavy"?

It's almost like an OS in itself and initially designed to be like a more capable and robust OS on top of rather constrained computers. In my experience it's trivial to shell or port out to the environment when I want to, and I also see people that I don't think of as highly skilled low-level programmers do things with NIF:s so that can't be exceptionally demanding either.

Yes it's definitely not heavy like a Java program that will cannibalize your RAM.

It's actually quite lean.

It will use all your cores without you asking (which is fantastic right?) but it's configurable AFAIK.

It will also use preemptive multitasking, so busy processes won't pin CPU cores at the expense of other tasks.

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