The Article Tells The Story of:
- A Forgotten Unix Successor That Made Networks Feel Like Local Drives – Plan 9 from Bell Labs wasn’t just an experiment—it rewrote how operating systems handle networks. But why didn’t it replace Unix?
- A Windows Clone That Works—Without Microsoft’s Code – ReactOS dares to do what no one else does: mimic Windows APIs from scratch. It runs Solitaire… but could it run your whole desktop?
- The Dead Multimedia OS Reborn as a Lightning-Fast Modern System – BeOS was built for speed and sound in the ‘90s. Haiku brings it back. Is it faster than Linux today?
- The Kernel That Should Have Powered Linux—but Didn’t – GNU Hurd was the original goal of open source. So why did Linus Torvalds beat it to the punch?
Linux Isn’t Alone in Open Source Anymore
Most people think of Linux when they hear “open source operating system.” But Linux isn’t the only one. Other open source systems have been developed over the years. Some started before Linux and still exist today. These systems offer different ideas about how an OS should work. Some were created for research. Others aimed to recreate popular commercial systems. Here are nine open source operating systems that aren’t Linux.
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Plan 9 From Bell Labs: A Network-Centered System
Plan 9 was created by the same team that helped build Unix. Rob Pike and his team at Bell Labs wanted to improve on Unix. Plan 9 took the idea that “everything is a file” and expanded it. You could browse network servers like you would browse local folders.
Plan 9 was built to be a distributed operating system. One machine could serve files. Another could provide compute power. Other machines acted as terminals. This design made it easy to share resources across a network.
Even though Plan 9 failed to gain commercial traction, it was later open-sourced. Developers still run it today, mostly for educational or research purposes. It also inspired features in other systems, including Linux.
Haiku: A Modern Take on BeOS
Haiku is an open-source version of BeOS. BeOS was designed in the 1990s by a team led by Jean-Louis Gassée, a former Apple executive. BeOS was fast, responsive, and built for multimedia. It supported multiple processors long before that became common.
BeOS didn’t survive in the market. Palm bought the company and shut it down. But Haiku keeps the project alive. It follows the same design goals and even supports BeOS software. Haiku offers a lightweight, clean desktop experience. If BeOS was the alternative to classic Unix, Haiku is like the alternative to Linux.
Minix: The OS That Inspired Linux
Minix was built by Andrew Tanenbaum to teach students about operating systems. It used a microkernel, which splits system tasks into small, modular pieces. Minix became famous after Linus Torvalds said it inspired him to write the Linux kernel.
Tanenbaum later updated Minix to focus on system reliability. It is now open-source and available for free. While Minix isn’t used much in daily computing, it still matters in education and research.
HelenOS: A Research Project with a Retro Look
HelenOS is another microkernel-based operating system. It was built as a research platform. It stands out with its Windows 3.1-style interface and clean modular design.
HelenOS is not ready for daily use. But it’s useful for those studying how operating systems handle memory, processes, and files. It works well in virtual machines and as a study tool for system developers.
AROS: Rebuilding the AmigaOS
AROS stands for “AROS Research Operating System.” It’s an open-source reimplementation of the classic AmigaOS. AROS tries to match the look and feel of AmigaOS while adding support for modern hardware.
AROS runs on standard PCs and other devices. Several versions exist, including AROS One, Icaros, and AspireOS. AROS offers a nostalgic experience and is useful for fans of the original Amiga.
ReactOS: An Open-Source Windows Clone
ReactOS tries to build a free, open-source version of Windows. It doesn’t copy Windows code. Instead, it uses clean-room engineering to avoid legal trouble. The goal is to run Windows software without using Microsoft’s operating system.
ReactOS aims to support modern Windows programs, but progress has been slow. Microsoft’s APIs change often, so developers have to rebuild parts of ReactOS frequently. Still, ReactOS is usable for simple tasks. It even includes classic features like Solitaire. You can download and try it on a spare machine or in a virtual machine.
FreeDOS: KeepainaMS-DOS Alive
FreeDOS recreates MS-DOS as an open-source system. It’s single-user, single-tasking, and uses the same text-based interface. It has the 640KB memory limit unless you use a memory manager.
FreeDOS is good for running old DOS games and business software. Some BIOS tools still only work in DOS, so FreeDOS is useful for tasks like flashing firmware. It also works well on vintage hardware or embedded systems where a full OS isn’t needed.
GNU Hurd: The Original Goal Before Linux
Before Linux, the GNU Project aimed to build its own kernel. That kernel was Hurd. Hurd is based on the Mach microkernel from Carnegie Mellon University. Hurd is still in development, but its pace has been slow.
Debian maintains a version called Debian GNU/Hurd. It works in virtual machines, but hardware support is weak. Hurd lacks many drivers that Linux supports. It’s more of a hobby system for now, but it reflects an important part of open source history.
The BSDs: Mature, Reliable Unix Alternatives
BSD stands for Berkeley Software Distribution. It began at the University of California, Berkeley in the 1970s. BSD systems helped shape the early internet by including TCP/IP support. BSD also helped grow Unix beyond Bell Labs.
There are four main BSD variants today:
FreeBSD:
FreeBSD is best known for its server tools and file system features like ZFS. Netflix and other companies use FreeBSD in production. It supports multiple CPU types and has a large user base.
NetBSD:
NetBSD focuses on portability. It runs on nearly every architecture, from PCs to older machines like the VAX or 68000-based Macs. Its motto is “Of course it runs NetBSD.”
OpenBSD:
OpenBSD is famous for security. Its developers aim to minimize vulnerabilities. OpenSSH and tmux came from OpenBSD. It’s a favorite for firewalls and secure servers.
DragonFlyBSD:
DragonFlyBSD split off from FreeBSD. It features the HAMMER2 file system, which supports snapshots and deduplication. It also supports virtual kernels for easier debugging.
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These Systems Still Matter Today
Linux isn’t the only open-source OS. These nine alternatives offer new ideas, unique designs, and strong histories. Some were built for research. Others aimed to replace older commercial systems. They all show that open-source software isn’t limited to just one kernel. Developers keep building new tools and exploring old ideas. If you want to try something different, these operating systems are a great place to start.
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