Free operating systems you might have never heard about

Are you looking for a free operating system? Of course, neither macOS nor Windows are free, so you shouldn’t even take them into consideration. Still, the choice of free operating systems is not limited exclusively by Linux and its distributions. Undeniably, Linux is a great option, however, if you enjoy trying new computer tools, you might be interested in checking the systems described in this article. We bet you hardly know at least one of them!

Free distributions and versions of commercial operating systems

There is a number of operating systems which can be used for free although they are based on other commercial projects. Here are some of them.


One of the most popular free operating systems other than Linux are Unix-based ones. A large group of operating systems are using BSD which is itself a distribution of Unix. A list of such systems include OpenBSD, PC-BSD, NetBSD and others. Not all of them are free, however, FreeBSD is a totally free operating system.

If you have ever used Linux, you might find FreeBSD quite similar to this popular operating system. In fact, some people even mistake Unix for Linux. Although Linux can be called a follow-up of original Unix since its creation was heavily influenced by this operating system, today they are not related at all. Unix continued its evolution as a separate OS.

If you are using Sony PlayStation 4, macOS or Juniper routers, in all likelihood, you have already come across some functionality of FreeBSD which is widely used due to the licence of FreeBSD which is quite permissive. Of course, it is not obvious that you are using this system as a part of other projects.


illumos is a project aiming to keep the OpenSolaris operating system developed by Oracle and discontinued in 2010 alive. In point of fact, in a year after stopping its OpenSolaris project, the company switched to Solaris 11.

Solaris 11 is an offspring of Solaris which itself was one of the first distributions of Unix. Thus, at some point illumos is quite close to Unix.

Free versions of old operating systems which are not used anymore

Those computer users who really enjoy vintage products, will be pleased to use free versions of the operating systems which were used decades ago.


Providing you have had a chance of using a computer running on an operating system with which a terminal was the only way for communication, you might be interested in getting back to legendary MS-DOS feeling nostalgia for those old devices.

Fortunately, you can still use this operating system which is available as FreeDOS. You can even play some of old games on a modern machine with the use of FreeDOS.

Another project of this kind is Syllable which is itself based on the AmigaOS clone, AtheOS.

Free clones of commercial operating systems

Clones of operating systems are not the same as versions or distributions of these systems. These are projects created with a view to be identical as commercial ones without the use of original code. Check some of them described below and you will understand the idea of clones.


ReactOs is a very peculiar project which is an operating system created with a purpose to be an alternative to Windows. Actually, the goal of the operating system is not be just like Windows, it wants to be Windows itself. What is the purpose of that?

Installing ReactOS on your machine allows you to use the programmes developed for Windows without purchasing Windows itself. ReactOS is a free open source operating system collaborating with the Wine project.


Haiku is a free clone of BeOS which is actually not used anymore today. This operating system was developed in 1995 by Be Inc as a system for BeBox and it was used for five years. There have been no updates for this operating system since 2000, albeit, the system managed to attract a group of fans. The result of this affection is Haiku which is an open-source clone of BeBox.

Free hobby projects created by single developers

Some people take their hobbies to the next level creating their own operating systems. In some cases, they even manage to do the entire work on their own without any help. Aren’t you curious to check some of such projects? Here you have a couple of choices to pick up from.

If you want to try an AmigaOS clone, pay your attention to AROS Research Operating System.


Visopsys is a quite long-term project since its creators has been working on it since 1997. Although it is not based on any operating system which has already been created by other developers, at some points it is using some pre-existing code. for that reason, the system has some wide-spread GNU tools and it can even look somewhat familiar to the people who have ever used KDE Plasma especially because of its icons.


It might be that DexOS is one of the most unique operating systems you can come across. That is so due to its untypical structure and interface which resemble playing on a console rather than using a regular computer. This experience becomes even stronger once you try playing games on DexOS.

Give this system a try especially since it is very small when it comes to its size.