Daniel Kahlenberg 573

sudo -i nix-store --gc

but then i. e. nix shell --no-substitute --option binary-caches '' .#nixosConfigurations.DANIELKNB1.pkgs.hello again gives:

error:
… while setting up the build environment
  error: getting attributes of path '/nix/store/w0cpwqkiim2b3cd8k0j5j1cz0s8kz87q-qemu-aarch64-binfmt-P-x86_64-unknown-linux-musl':  
No such file or directory

Setup full disk encryption on a Hetzner cloud CX42 machine. No fancy SSH unlock: you have to go to their web based terminal to enter the disk password on boot.

Notes:

Their web based terminal is /weird/. You can paste things, but it looks like it's set up for a german keyboard, and many characters change ("http://" into "http;//"), sometimes it converts everything to lowercase after a while, sometimes it enters some capslocks mode. I ended up typing as much as possible by hand, and only use alphanumeric passphrases so there are no surprises when copy-pasting those.
The (qemu) virtual machine doesn't use EFI, but Legacy Boot. Most setup instructions I found are for EFI systems.

there we go

In the Hetzner UI click the server in the list, go to tab [ISO Images], search for "nix", and mount "NixOS 24.05 (x86_64/minimal)"
Reboot, and open the terminal. (the's a button on the top with [>_], which is a shortcut for the terminal)

Getting started with the Nix ecosystem

What is this article about?

When I first started to learn how to use NixOS, the Nix package manager, and how to work with the Nix language, I was overwhelmed. While it did not take me too long to (sort of) get into it, it was not the most pleasant experience. I would say that there is not really a single source of truth, like Arch Linux users have with the ArchWiki, where you can basically look up everything. Instead, the information is spread across many different sources, which can make it difficult for beginners to find out how to do what they want to do.

The "modern nix CLI", also known as "nix3 cli", is another thing that can cause confusion when you are just starting your nix journey. There are some commands that look almost exactly the same, such as nix shell compared to nix-shell or nix-build compa

https://learn.microsoft.com/en-us/windows/wsl/disk-space#how-to-locate-the-vhdx-file-and-disk-path-for-your-linux-distribution

https://stephenreescarter.net/how-to-shrink-a-wsl2-virtual-disk/

wsl --shutdown
wsl --manage NixOS-Groundtruth -s false
(Get-ChildItem -Path HKCU:\Software\Microsoft\Windows\CurrentVersion\Lxss | Where-Object { $_.GetValue("DistributionName") -eq 'NixOS-Groundtruth' }).GetValue("BasePath") + "\ext4.vhdx" | Set-Clipboard
diskpart
> select vdisk file="\\?\C:\Users\dkahlenberg\NixOS\ext4.vhdx"

Implementing complex numbers and FFT with just datatypes (no floats)

In this article, I'll explain why implementing numbers with just algebraic datatypes is desirable. I'll then talk about common implementations of FFT (Fast Fourier Transform) and why they hide inherent inefficiencies. I'll then show how to implement integers and complex numbers with just algebraic datatypes, in a way that is extremely simple and elegant. I'll conclude by deriving a pure functional implementation of complex FFT with just datatypes, no floats.

Yes, there are several ways to do this, but none of them are as direct and simple as git v2.1.2; htop v1.2.3 and come with a lot of caveats.

aside
Specifying versions for programming language packages are possible too, but that topic seems to be even messier. The most promising standardization effort to date is [dream2nix][1].

0. Methods

That is, available at the time of this writing:

	let
	nixbuildDomain = "eu.nixbuild.net";
	nixbuildKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPIQCZc54poJ8vqawd8TraNryQeJnvH1eLpIDgbiqymM";
	nixbuildPlatforms = [ "x86_64-linux" "aarch64-linux" ];
	nixbuildFeatures = [ "big-parallel" "benchmark" "kvm" "nixos-test" ];
	nixbuildSSH = ''
	Host eu.nixbuild.net
	PubkeyAcceptedKeyTypes ssh-ed25519
	ServerAliveInterval 60
	IPQoS throughput

	import sys
	import functools

	callstack = []

	@functools.cache
	def lookup(func):
	try:
	parts = func.split(":")
	with open(parts[0]) as f:

	{
	description = "A nixos cloudinit base image without nixos-infect";

	inputs = {
	nixpkgs.url = "github:nixos/nixpkgs";
	};

	outputs = { self, nixpkgs }:
	let
	system = "x86_64-linux";

	import com.intellij.coverage.CoverageExecutor
	import com.intellij.execution.ExecutorRegistry
	import com.intellij.execution.RunManager
	import com.intellij.execution.RunnerAndConfigurationSettings
	import com.intellij.execution.application.ApplicationConfiguration
	import com.intellij.execution.application.ApplicationConfigurationType
	import com.intellij.execution.executors.DefaultDebugExecutor
	import com.intellij.execution.executors.DefaultRunExecutor
	import com.intellij.execution.junit.JUnitConfiguration
	import com.intellij.execution.junit.JUnitConfigurationType