When it comes to the operating systems you can actually use on your computer, there are really only three main ones that are ever brought up. You have Windows 11, macOS, and Linux (or, more accurately, Linux-based operating systems). Most people wouldn't ever think there's anything beyond that, especially because so many operating systems are based on Linux, whether it's Ubuntu, NixOS, or even Android.

But that would be an incorrect assumption. In fact, there have been a few operating systems throughout the years that are built completely from scratch or based on different projects altogether that have nothing to do with Linux, and some of them are actually usable. For the most part, at least. So let's take a look at a few operating systems you can take for a spin if you want to try something really unique.

6 FreeDOS

For those nostalgic for the command line

I'll be honest right out of the gate and say that command line interfaces aren't really for me, and along with the fact I wasn't even alive when MS-DOS was relevant, that makes FreeDOS not particularly interesting to me. However, FreeDOS is still a commendable and interesting effort. It's entirely based on the command line, but it does a good enough job helping you understand the basic concepts, and while there isn't much included in the package out of the box, there is at least a text editor, and you can do all kinds of file management operations.

What makes it a lot more interesting if you really want to get into it, there are many more apps you can install using the "bonus CD" that's also provided on the FreeDOS website. These include things like a handler for 7z files, or a calculator. There are a few possibilities here, and you can also run it off of a live USB if you need to make some changes to your hard drive or something. FreeDOS is a fairly mature project that, despite its apparent simplicity, has become quite good at what it aims to do.

5 AROS

Interesting, but confusing

I feel obligated to include AROS because in some ways, it's one of the most mature options when it comes to non-Linux operating systems. It has a desktop interface that actually looks very well developed with all kinds of custom icons and imagery, and even in a VM, allowed for fairly high resolutions for the display, so I was very hopeful going in. However, this Amiga-based system was a little much for me.

A lot about AROS still feels somewhat familiar these days, but the UI and UX paradigms at play here are very confusing to get used to, and I had a hard time doing just about anything. I couldn't find a web browser or anything that would allow me to connect to the internet, even though a repository of extra packages does exist.

If you have the time and mindset to really dive in and learn everything, AROS honestly looks very promising, and out of the box, it already has a lot of basic tools like a text editor, calculator, and clock. There's even a built-in screenshot tool, something you really don't see in most of the options on this list. I just couldn't get much deeper than that, personally.

4 Minix

Well... kind of

Saying you can daily drive MINIX is definitely more than a little generous for the vast majority of people, but I did manage to get it working to some extent and it is... usable. The latest development release of MINIX is already many years old, so you could say the project is dormant, but it does function. The OS is very barebones and mostly terminal-based to start, but it does include X11, and once you launch it, you get a fairly basic window manager.

I managed to install a web browser, Links, which is available in a GUI version that can even load some images, making it almost acceptable by modern standards. MINIX can install and run a lot of FreeBSD packages, though, and it has a big focus on reliability, so in some specific use cases, it may actually work for you. It's certainly not for everyone, but it functions. It's easy to imagine things would be a bit more interesting if the project were still actively supported.

3 HelenOS

A simple but functional OS

If we're talking about very simple operating systems, HelenOS is a perfect example, but it still manages to be decently user-friendly. The default installation for HelenOS will give you a simple GUI with a taskbar and multiple window support, and out of the box, you get some basics, including an image viewer, text editor, a basic calculator, and even a simple game of Tetris.

Otherwise, you get a graphics demo and a UI demo showing what can be done with the OS, but there isn't a lot in terms of actual tools here, such as a web browser. But considering HelenOS is a measly 25MB in size, it's hard to complain. You can run this on pretty much anything and it gives you a usable operating system. That's still very impressive.

2 Haiku

A different take on BeOS

BeOS was a notable project back in the late 90s and early 2000s, and it actually managed to inspire and serve as the basis for another operating system, called Haiku. This OS may not have all the bells and whistles of a modern OS, but it does have a lot of the basics down already. You can browse files, modify various system settings, and even browse the internet, which allowed me to open the XDA homepage or Google.

I was also able to open and browse YouTube inside a virtual machine (albeit slowly), but video playback didn't work. However, just for the sake of testing, I did download an MP4 file and it works perfectly using the built-in video player on Haiku. It actually seemed to run far more smoothly than I would expect from something running in a virtual machine, so I was fairly impressed. There's even a couple of games in here, and a Chart app that seems to be a graphical demonstration, with small dots flying around in a 3D space, and the animation also runs very smoothly, even in a VM.

The UI is obviously different, but many of the basic paradigms of a desktop OS will feel somewhat familiar. Apps open in windows, which you can move around and resize, as well as maximize. Rather than a typical taskbar, your basic control center actually lives on the left side of the screen and takes up a good chunk of it, but this allows it to list all your open apps without much of an issue if you have a lot of them. As with most of these options, you won't get very far if you have complex needs, but Haiku seems totally usable on a base level.

1 ReactOS

It's Windows... but not

ReactOS is a very interesting operating system. The creation of this OS came about through reverse engineering Windows XP, and the team basically managed to recreate the Windows XP experience without using any of Microsoft's actual code. That means ReactOS looks very familiar if you've used XP, and it can even run a lot of the apps you would have used on a Windows XP machine. Heck, if you run it in a VirtualBox VM, you can even use the Guest Additions CD designed for Windows XP to improve the experience on ReactOS. It's seriously impressive that the team managed to accomplish this.

Of course, it's still far from perfect, and in the past I've tried to run this OS on real hardware and failed, but within VirtualBox, it's surprisingly capable. ReactOS has all the things you'd expect, like a File Explorer, Control Panel, and even a version of Internet Explorer, though you can also install other browsers such as Firefox or Chrome. Of course, these have to be old versions of the browsers that supported Windows XP, but still. In fact, you can install a lot of programs on ReactOS, and it even comes with an application manager to make it easier to find apps that work. That even includes a game like Cave Story, which, if you haven't played it before, you absolutely should.

ReactOS is one of the most capable operating systems on this list, though in my brief time with it, I was having a lot of trouble loading webpages (even though downloading programs worked fine). With some patience and tinkering, though, this can be pretty fun to mess around with.

There's a vast world of operating systems out there

Even though I spent some time with all of the operating systems above, this is still just a sampling of the many operating systems out there that you might want to give a shot. FreeBSD is a relatively popular one, and a lot of BSD-based options also exist. On top of that, you have even crazier options like TempleOS. You probably wouldn't want to use these in the long term, but if you enjoy experimenting, there's a ton to dive into. That being said, the options above are some of the most accessible these days, so they're my top recommendations.