* Introduction
NixOS is a reproducible, scalable operating system that is used in server
infrastructure. This month, I decided to torture myself and run it on a
personal computing machine.

Just kidding, it's really good, and currently the only operating system
that can do what NixOS does is GNU Guix. What's particularly interesting
is that when GNU and Linux people say, "Look! Finally something that only Linux
can do well!", there's usually some tool out there that can get most of the
behavior out of MacOS and Windows, or maybe there's even a "better" version
of it on those two operating systems. However, NixOS and Guix are truly
unique and their usage truly cannot be replicated on either of the two systems.
I will talk about NixOS in particular because that is the operating system I
currently use.

** So What's the Pitch?
When you write a configuration for NixOS, it works forever until the packages
stop being hosted, meaning as long as the NixOS team exists, your particular
version of NixOS, running your particular configuration, will /always/ work
in the same way. It will even work the same way across multiple computers, given
you don't put in too much hardware-specific configuration into your /configuration.nix/
file. Interestingly enough, it is possible to /make sure/ that network copying
errors don't happen, and make the system almost completely deterministic. Essentially,
you can /define your operating system as a function that takes in inputs and outputs/,
and then /specify those inputs in a specific way/, which then allows you to
/ensure the reproducibility of your environment/.

On top of that, it is possible to /roll back/ your configuration. That is,

You can see why this might be used in industry for mass deploying servers, and you might
even understand why one might use this type of system for docker containers, but /why on earth/
would someone run it as a personal machine? Well, there are a couple of good reasons to do so:
1. You like how your computer operates.