After a while the operating system fades into the background like the wiring inside a wall, something you depend on every day without ever wondering how it got there.

I was no different, and I used Windows for years without asking why it worked the way it did, until university introduced me to Linux and I started noticing things: why a particular command existed, why I could change one setting but not another, and who had decided any of this in the first place.

That is when I learned something that changed how I see technology, which is that an operating system is not a law of nature but a collection of decisions, made by different people who sometimes made very strange and very interesting choices. Here are a few that fascinated me, even if you never plan to install any of them.

Qubes OS: one laptop, many lives

Imagine you receive a suspicious file that you need to open but don’t trust, which on a normal computer means opening it and crossing your fingers.

Qubes OS takes a different view and splits your machine into sealed compartments, one for studying, one for social media, and one just for risky files, all sitting on the same screen but unable to easily touch each other, so that if the dodgy file does something nasty, the damage stays inside its box.

The idea is surprisingly human, since we don’t leave our bedroom, office and bathroom as one open room, and Qubes shows that security is not only about strong passwords but also about how you arrange things, even though it is far from perfect and demands fairly capable hardware.

Plan 9: what if everything was a file?

Plan 9 was an experimental system built at Bell Labs, the same place that gave us Unix, and it took the idea of treating resources like files and pushed it much further, so that something on a faraway machine could appear on yours as if it were sitting in an ordinary folder.

Each program could even be given its own custom view of the world, seeing only the things it needs, which is a surprisingly elegant way to think about sharing and separation. It never became mainstream, and nobody is suggesting you replace your laptop with it, but several ideas that feel modern today were being explored there decades ago, a reminder that some systems are built not to win but to ask questions the rest of us haven’t thought of yet.

FreeBSD: the quiet professional

FreeBSD doesn’t try to look pretty, and it tends to live in the background of servers and networks, doing serious work while nobody notices. Two of its tricks are worth knowing: jails, which are lightweight sealed-off spaces where a program can run without wandering across the rest of the machine, and a storage system called ZFS, which can take snapshots of your data the way a video game lets you create a save point before a risky battle. If something goes wrong, you simply go back, and that habit of planning for failure is a big part of what separates writing code that works from running software that lasts.

MINIX 3: what if the core did less?

Every operating system has a heart called the kernel, which holds the most power over your machine, and the catch is that the more code you stuff into that powerful core, the more places a bug can hide and cause chaos. MINIX 3 keeps the core tiny and pushes almost everything else out into separate pieces, so that when one of them breaks the whole system doesn’t go down with it. Engineers have argued for decades about whether a large, powerful core or a small, careful one is better, and while it sounds technical, it is really a design philosophy anyone can relate to: do you build one giant machine that does everything, or many small parts that can fail safely? There is no single right answer, which is exactly what makes it fun.

Haiku: the desktop that took a different road

Look at almost any computer today and you will notice they all feel roughly the same, with windows, menus, folders and a taskbar somewhere, which makes it easy to assume that this is simply what a desktop has to be.

Haiku, an open-source system inspired by BeOS, an old operating system built around speed and multimedia, says otherwise, offering an experience familiar enough to follow but different enough to make you stop and think. It also teaches a slightly painful lesson, which is that technical excellence does not guarantee success, because apps, hardware support and developer attention matter just as much, and plenty of great ideas lose to merely good ones with better timing and bigger crowds.

TempleOS: one person, one whole world

Then there is the strangest entry, TempleOS, created by a single programmer named Terry A. Davis, who built almost everything himself, including the system, the programming language, the compiler, the graphics and the applications, all designed around his own religious vision and running on a fixed 640×480 screen with just 16 colours.

You would never want it as your everyday system, but the scale of the achievement is hard to ignore, because we normally think of an operating system, a language and a compiler as separate products made by separate companies, and seeing one person build the lot makes you realise how many layers sit beneath every app you open without a second thought.

All of this brings me back to Linux, which is the one on this list you can realistically live with every day, and which is where my own curiosity began.

The first reason to consider it is control, since Linux lets you change almost anything, from how the desktop looks to how the system starts up, and that stops the computer from feeling like a sealed product and starts making it feel like something you actually own.

The second is learning, because working with the terminal, the filesystem, permissions and package managers teaches you how a computer really operates in a way that clicking through menus never will, and for anyone studying or planning to work in technology, that understanding really pays off for years.

It is also free and open source, so you can read how it works, and it is often lighter than its competitors, which means an old laptop that struggles with Windows can sometimes feel new again with a lightweight distribution. Many developers also find that programming tools, servers and cloud systems feel more natural there, since so much of the software world runs on Linux behind the scenes.

It is not perfect, of course, and an honest account has to admit that some software, such as certain design and office programmes and a few games with strict anti-cheat systems, may not work well, and that the first few weeks can be frustrating.

The good news is that you don’t have to commit, because you can try a beginner-friendly distribution like Ubuntu or Linux Mint from a USB stick without installing anything, run it in a virtual machine, or keep Windows alongside it in a dual-boot setup until you feel comfortable.

I used to use Windows, and now I use Linux, which doesn’t make one of them right and the other wrong; it simply means I stopped assuming my computer worked the way it did because it had to.

Every tool you use is built on assumptions someone once made, and once you notice that, you start asking better questions about everything around you, which is the real upgrade, and it doesn’t need an installation at all.

Curious? Qubes OS, Plan 9, FreeBSD, MINIX 3, Haiku and TempleOS all have public documentation online, and an afternoon with any one of them is a good start.