I make the specification of non-linux because otherwise this would just become a thread full of obscure distros that do the same thing as a million other distros.
Some lesser known OSs:
- AROS - based on Amiga OS, has some derivatives like IcarOS and MorphOS
- Haiku - based on BeOS
- Redox - Unix-like, made in Rust (might technically count as linux?)
- Serenity - Unix-like, very late 90s look and feel
- Kolibri - Tiny OS, the image is ~44MB. It also has a smaller version that fits in a single floppy.
- PhantomOS - When 3 Russians decide to turn everything about a typical OS upside down.
Plan 9
It is an absolutely revolutionary OS by some of the original creators of Unix, that extends its core concepts in more coherent and elegant ways into the world of modern computing, instead of having everything from networking on up be tacked on by people who were perfectly capable but lacked the vision.
Examples:
Instead of NAT, if one machine on your network has the internet and the others don’t, you can say “use that other machine’s network stack now” and boom everything works. Your machine knows what its real external IP address is, it can listen on world-facing ports on the other machine as it needs to, everything works and is simple.
There’s a command for “run the rest of this session’s commands on that other machine’s CPU / memory” and it all just works. The sensation is that your computer just got magically faster.
Etc etc. I actually haven’t played with it extensively, and deployment is so limited that I’m not sure how useful it would even be, but if you are a fan of well made OSs that do things in a genuinely different fashion, it is objectively the best option to play around with. sdf.org has a place you can get an account on their Plan 9 machines and they do little free beginner courses in it over livestream.
I’ve come across Plan 9 in the past and assumed it was only really useful in a “time-sharing” type scenario like OG Unix used to be used for. Am I wrong about that?
Think less about time sharing and more about using all the computers you own together.
You would have a netbook with no compute power as your UI sitting on your couch. You could connect to your beefy desktop to do all the computations for your video editor or playing a game and never have to be sitting at your desk.
You could also have a big file store device with lots of drives to store stuff.
We can do some of this now, I ssh into my desktop from my couch and have a NFS in the basement. But they all operate as separate devices that i have to really work at getting to operate together. Plan9 was designed where you’d just pick devices off of the network and the tasks operated normally. Pick your video card, local or over the network to the beefier GPU.