Why? is also how you resolve the XY problem[1], and asking it five times[2] is the basis of a root cause analysis, and as any parent will tell you[3] is part of raising children, and is also what you should seek to put into a commit message[4].
Why? is almost always a good question to ask.
1. http://meta.stackexchange.com/questions/66377/what-is-the-xy...
2. https://en.m.wikipedia.org/wiki/5_Whys
3. https://m.youtube.com/watch?v=sahSAMj8OIY
4. https://github.com/erlang/otp/wiki/writing-good-commit-messa...
In How to Accept Over-Engineering for What It Really Iserlang
otp
Erlang2009–2026
erlang / otp
otp
Erlang/OTP
73Distinct people
93Mentions
1Explicit recommenders
12.4KGitHub stars
What to know before exploring
What it is
Erlang/OTP
GitHub
Where it is used
No documented product use was verified in the last source check.
What people are saying
It has built-in maps now! (like dicts or hashes in other languages). http://www.swi-prolog.org/pldoc/man?section=maps That is exciting. I'd want to play with it again. I like…
rdtsc used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
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This week on Hacker News
Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 9:02:44 AM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year93 dated mentions
Observed mentions: 2009-11-25 17:20:26 UTC to 2026-05-11 21:10:48 UTC.
* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2009 | 2009-01-01 00:00:00 UTC | 2010-01-01 00:00:00 UTC | 1 | 1 | 0 |
| 2010 | 2010-01-01 00:00:00 UTC | 2011-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2011 | 2011-01-01 00:00:00 UTC | 2012-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2012 | 2012-01-01 00:00:00 UTC | 2013-01-01 00:00:00 UTC | 2 | 2 | 0 |
| 2013 | 2013-01-01 00:00:00 UTC | 2014-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 9 | 0 | 9 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 13 | 2 | 11 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 11 | 3 | 8 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 5 | 2 | 3 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 9 | 0 | 9 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 16 | 5 | 11 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 3 | 1 | 2 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 2 | 1 | 1 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 5 | 0 | 5 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 8 | 1 | 7 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2026 (partial) | 2026-01-01 00:00:00 UTC | 2027-01-01 00:00:00 UTC | 1 | 0 | 1 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
Erlang/OTP
Erlang is a programming language and runtime system for building massively scalable soft real-time systems with requirements on high availability.
OTP is a set of Erlang libraries, which consists of the Erlang runtime system, a number of ready-to-use components mainly written in Erlang, and a set of design principles for Erlang programs. Learn more about Erlang and OTP.
Learn how to program in Erlang.
Examples
There are several examples on the website to help you get started. The below example defines a function world/0 that prints "Hello, world" in the Erlang shell:
-module(hello).
-export([world/0]).
world() -> io:format("Hello, world\n").
Save the file as hello.erl and run erl to enter the Erlang shell to compile the module.
Erlang/OTP 24 [erts-12.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]
Eshell V12.2 (abort with ^G)
1> c(hello).
{ok,hello}
2> hello:world().
Hello, world
ok
Learn more about the Erlang syntax of modules, functions and expressions on Erlang.org.
Installation
Binary Distributions
Erlang/OTP is available as pre-built binary packages by most OS package managers.
apt-get install erlang
Compiling from source
To compile Erlang from source, run the following commands. The complete building and installation instructions can be found here.
git clone https://github.com/erlang/otp.git
cd otp
Checkout the branch or tag of your choice
git checkout maint-27 # current latest stable version
Configure, build and install
./configure
make
make install
Alternatively, you can use Kerl, a script that lets you easily build Erlang with a few commands.
Bug Reports
Please visit our GitHub Issues page for reporting bugs. The instructions for submitting bugs reports can be found here.
Security Disclosure
Please do not report security vulnerabilities through public channels, like
GitHub issues, discussions, or pull requests.
Please disclose the security issues following our SECURITY guidelines.
Contributing
We are grateful to the community for contributing bug fixes and improvements. Read below to learn how you can take part in improving Erlang/OTP. We appreciate your help!
Contribution Guide
Read our contribution guide to learn about our development process, how to propose fixes and improvements, and how to test your changes to Erlang/OTP before submitting a pull request.
Help Wanted
We have a list of Help Wanted bugs that we would appreciate external help from the community. This is a great place to get involved.
Awesome-Erlang
You can find more projects, tools and articles related to Erlang/OTP on the awesome-erlang list. Add your project there.
License
Erlang/OTP is released under the Apache License 2.0.
For any license inquiry, please send an email to opensource@ericsson.com
%CopyrightBegin%
SPDX-License-Identifier: Apache-2.0
Copyright Ericsson AB 2010-2025. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
%CopyrightEnd%
Read the full README on GitHubWhat Hacker News says
13 sourcesYap. Erlang 19 (latest version) switched to using a smaller spawner executable and spawns all OS processes from there by forking. So it forks something restricted and small not the whole VM.
Here are the details of how it works:
https://github.com/erlang/otp/blob/a5256e5221aff30f6d2cc7fab...
They also claim a 3-5x speedup for launching external commands because of it. So there is a nice performance boost as well.
So basically can add 4th strategy -- fork once a small program at the start, then fork from there from then on.
In Fork() without exec() is dangerous in large programsI think it's probably more of a consequence of the long long discussions that were had at https://github.com/erlang/otp/pull/960 -- with 15 participants from the OTP team, regular Erlangers, and I'm sure a few Elixir people too.
My idea here is not to remove merit from Elixir in helping the ecosystem, but in pointing out that the Erlang community itself is expanding on these ideas of involvement and a more open design.
In Erlang/OTP 19.0 has been releasedErlang is written in a ton of quite readable C and assembly. If you like delving into the internals of advanced software, it's well worth a read. Take the HiPe compiler for example:
https://github.com/erlang/otp/tree/OTP-19.0/erts/emulator/hi...
It deals with running native and interpreted program code together, just reading the comments gives you a feel for the kind of low level concepts that go into making such an interpreter. I like this one:
/*
* Native code calls an emulated-mode closure via a stub defined below.
*
* The closure is appended as the last actual parameter, and parameters
* beyond the first few passed in registers are pushed onto the stack in
* left-to-right order.
* Hence, the location of the closure parameter only depends on the number
*
Read the rest
of parameters in registers, not the total number of parameters.
*/
Not only that but ssh protocol in R19 will be implemented as a gen_statem, providing a real life usage example for it.
I also liked that Ericsson engaged with the community and considered input and updated code accordingly as they worked on it.
You can see the whole process and discussion in:
https://github.com/erlang/otp/pull/960
In Finite state machines with AkkaErlang R19 Release Candidate Available
106 points · Open discussionI was hoping that i'd agree but check the code for Mnesia for example: https://github.com/erlang/otp/blob/maint/lib/mnesia/src/mnes...
Numerous functions missing essential code documentation all spread in a single file, with commented out code committed in git.
In Ask HN: What are examples of GitHub repositories with high code quality?https://github.com/erlang/otp is one of the best examples I can think of. It's reliability focused engineering from a major engineering firm.
In Ask HN: What are examples of GitHub repositories with high code quality?I think this is the PR so far:
https://github.com/erlang/otp/pull/858
In Why Erlang MattersThis unfortunately breaks down with (bad acting) NIFs. Thankfully you can mark 'em as the dirty evil little things that they are (with negligible overhead): ERL_NIF_DIRTY_JOB_CPU_BOUND. [1]
I implore anyone interested in Erlang or its surrounding languages, to read its source code. [2] More specifically, the BEAM. I'll warn you that it's very 80's hackeresque, but in a good way. Incredibly pragmatic. The way they achieve their world-class scheduling? Tip: not via a perfect theoretical design cooked up in some comp-sci lab. [3] If you've been following game engine design within the last 9 years or so, you'll probably have a good idea of how they do it. [4][5]
[1]: https://medium.com/@jlouis666/erlang-dirty-scheduler-overhea...
[2]: https://github.com/erlang/otp/tree/maint/erts/emulator/beam
[3]: https://hamidreza-s.github.io/erlang/schedul
Read the rest
ing/real-time/pr...
[4]: http://blog.molecular-matters.com/2012/04/05/building-a-load...
[5]: There's a hell of a lot of depth to this problem domain. Charles Bloom's guiding principles for Oodle are spot, and well worth a look.
There is a successor to gen_fsm in Erlang being developed -- gen_statem.
Here is the work in progress docs:
http://erlang.org/~raimo/doc-7.2/lib/stdlib-2.7/doc/html/gen...
And the community discussion:
https://github.com/erlang/otp/pull/960
In Rage Against the Finite-State MachinesThanks, yours was finally the comment I was hoping for.
Could you point me at the right place to read (or read about) the beam sources? I'm looking at https://github.com/erlang/otp/wiki/Routemap-source-tree -- is there something better?
In Managing two million web servers