Show HN: Crazierl – An Erlang Operating System(crazierl.org)
50 pointsby toast09 hours ago6 comments
  • tombert8 hours ago
    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.

  • mixedbit8 hours ago
    Is the OS implemented from scratch, or is it a stripped down version of some existing OS?
    • toast08 hours ago
      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...

      • asenchi5 hours ago
        DragonFlyBSD would be really interesting here as well since its kernel has Light Weight Kernel Threads that use message passing. Similar in shape to Erlang/BEAM. Though I guess you've built the kernel in Erlang... so wrong abstraction.
        • toast04 hours ago
          My kernel is in C. BEAM is in userspace. Most of the drivers are in userspace too. Turns out, if you let userspace mmap whatever address it wants to, and have access to all the i/o ports, plus have a way to hook interrupts, you can write drivers in userspace.

          You could run beam as init with an existing kernel, but I wanted to explore something with less kernel.

  • lightandlight6 hours ago
    > browser-based demo

    Wait, so is the browser running a JavaScript build of Qemu? /

  • zephyrwhimsy4 hours ago
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  • zephyrwhimsy4 hours ago
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