My personal blog
hauleth.dev
blog
Fix some Markdown styling issues
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content/post/beam-process-memory-usage.md
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content/post/beam-process-memory-usage.md
···
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Elixir 1.14.5 (compiled with Erlang/OTP 25)
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```
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> Note no JIT as Nix on macOS currently[^currently] disable it and I didn't bother to enable
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> it in the derivation (it was disabled because there were some issues, but IIRC
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> these are resolved now).
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> Note no JIT as Nix on macOS currently[^currently] disable it and I didn't
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> bother to enable it in the derivation (it was disabled because there were some
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> issues, but IIRC these are resolved now).
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[^currently]: Nixpkgs rev `bc3ec5ea`
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content/post/eli5-ownership.md
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content/post/eli5-ownership.md
···
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doesn't matter, but there will be only one owner. You can do whatever you want
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with such note but with that power comes, not so great, responsibility: after
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you are done with this book you will need to get rid of it. Since you are a law
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abiding citizen you will recycle the note in the appropriate receptacle, but it is your
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responsibility to do it. Of course this is not the only way to deal with a note. You
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can also give it to someone and then it will be hers or his responsibility.
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abiding citizen you will recycle the note in the appropriate receptacle, but it
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is your responsibility to do it. Of course this is not the only way to deal with
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a note. You can also give it to someone and then it will be hers or his
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responsibility.
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To rephrase it in the Rust way, it would look like this:
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···
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But some notes are even shorter than that. They are so short and easy to clone
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that it is much easier to clone them every time, instead of explicitly
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calling the method. Like when you give your phone number to a hot girl at the
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bar, the `Copy` trait automatically clones your note so the other has their own copy.
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calling the method. Like when you give your phone number to a hot girl at the
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bar, the `Copy` trait automatically clones your note so the other has their own copy.
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Again, this is for small types that can be mechanically copied each time when needed.
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```rust
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content/post/port-love.md
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content/post/port-love.md
···
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+++
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title = "For F**k Interface"
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date = 2025-11-03
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[taxonomies]
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tags = [
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"beam"
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]
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+++
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Erlang provides multiple forms of FFI:
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- C Nodes - external applications, that (despite the name) can be implemented in
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any language, not just C. It communicates with BEAM VM via Distributed Erlang,
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and for all needs and purposes looks like "regular" Erlang node in cluster
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(just can be implemented in any language). It provides greatest isolation, as
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technically these two nodes do not even need to be on the same machine.
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- Ports - an external program, that is ran by BEAM VM and then communicates
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via unnamed Unix pipes[^pipes]. It relies on OS for process isolation, which
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mean that in the isolation level ladder it is placed in the middle.
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[^pipes]: I do not know what this mechanism is called on Windows, sorry.
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- NIF (Native Implemented Function) - with that you write dynamic libraries,
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that are loaded into the same address space as BEAM VM and then you can call
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functions from this module like "normal" BEAM functions. That gives the best
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performance out of three, but at the same time it isolates least. Writing well
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behaving NIF is not easy, as you need to take into consideration the function
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run time or use dirty scheduler, unhandled runtime errors will cause problems
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for whole VM, and stuff like that.
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Technically there is another FFI option, but that one is legacy:
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- Port Drivers - mostly a legacy stuff, these are modules, that are loaded
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within the same address space as BEAM VM, but communication between different
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languages is done like with Ports (just within single memory space). That mean
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that you have disadvantages of both Ports (indirect communication) and NIFs
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(system destabilisation in case of error), but without any real benefit.