This would solve a major issue with SteamOS. The SteamOS itself is immutable/read only as you know. This means, one cannot install or make changes to the core system (it is possible, but that is temporarily until update will revert those changes back). That is why we have the Flatpak support. But many software are not available there (especially CLI tools, if you use them).
This is where the Nix package system comes into play. In short, it allows for installation of programs without touching the immutable part of SteamOS in a controlled and safely manner. These would persist even on SteamOS system updates. For a better explanation, have a look here: https://nixos.org/guides/how-nix-works.html
Valve confirmed: https://github.com/NixOS/nix/issues/7173#issuecomment-1603858003 that Nix package support will be integrated into SteamOS! That’s huge. In example I have tools which I cannot distribute easily for Steam Deck users, because Flatpak does not support CLI apps. Nix would solve this issue!
This is probably not something I will make use of at all in the near future but I still absolutely love that they are doing this! Valve is really carving out a path forward for linux as a whole and eventually normal folks - not just enthusiasts - will be able to drop Windows completely.
If Valve really allows nix then future mods & stuff can be provided through that. As long as a person manages to create a nix config for whatever everyone can let nix replicate that on any device anywhere and anytime.
That guy managed to install and run Blizzard games? Share the config.
That other guy is able to tweak an intricate feature? Just share the config.
How much knowledge do gamers need to apply that config? Close to nothing.
It’s a really neat thing.
Whoa! Definitely not something I expected, but will happily take it!
What does ‘making changes to its core system’ mean? I though people were able to use steam deck as a proper pc already, installing new apps on it and stuff like that?
SteamOS core system is locked as read-only. That is what immutable means. In example you cannot install applications using the core system management named “pacman” (short for package manager). There is a toggle in SteamOS to disable this read-only functionality, but with next system update all changes are reverted.
But how do you install applications on SteamOS? You certainly can do, right? Yes! That’s the store it offers, which uses a different concept called Flatpak. These are programs you can install without touching the core system. And therefore these are persistent, even on system updates. And they are similar to Android programs in a sandbox.
I assume you are not familiar with how Linux systems operate. Imagine this like Android, where you are only allowed to install from a store, which cannot make changes to the Android core, but only install applications on a secured way. But that is limited. Or imagine a game console where you can only install games and programs which the store has. And it lacks Command Line Interface programs in example or many other tools not found in the official store. That’s how SteamOS works at the moment.
And here comes the Nix packagement into play. This is a different system again. You can think of it like Flatpak, meaning any changes to it would be sandboxed and do not touch the core system. This allows for Command Line tools and some other stuff, as discussed before. Nix packages will be part of the next big update of SteamOS.
What is the current state on SteamOS as a desktop replacement? My understanding is that the currently downloadable version is only the SteamDeck version and not suitable as a Windows replacement for the desktop.
I don’t know what you mean by “steamdeck version”, but afaik the SteamOS you can download from steam is version 2 which is really old by now while the Steamdeck runs version 3 and is still not available for download outside of it. Mind you it isn’t just a major version change but they even changed the linux OS it’s based on, moving from Debian to Arch.
As for the replacement for desktop, the Steamdeck (and with it SteamOS 3) launched with full desktop mode available and while the core system is immutable as discussed, it’s still a fully functional desktop OS and as such it depends on your personal needs how much of a windows replacement it can be, just like any other linux OS. Also you might need a dock or other USB hub to attach a keyboard and mouse if you need them, but there is onscreen keyboard and touchpad on the steamdeck available.