Browse free open source C Operating Systems and projects below. Use the toggles on the left to filter open source C Operating Systems by OS, license, language, programming language, and project status.

  • Auth0 for AI Agents now in GA Icon
    Auth0 for AI Agents now in GA

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  • Grafana: The open and composable observability platform Icon
    Grafana: The open and composable observability platform

    Faster answers, predictable costs, and no lock-in built by the team helping to make observability accessible to anyone.

    Grafana is the open source analytics & monitoring solution for every database.
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  • 1
    ReactOS

    ReactOS

    An operating system based on the best Windows NT design principles

    ReactOS is an open source effort to develop a quality operating system that is compatible with applications and drivers written for the Microsoft Windows NT family of operating systems (NT4, 2000, XP, 2003).
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    Downloads: 5,237 This Week
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  • 2
    CachyOS

    CachyOS

    Blazingly Fast & Customizable Linux distribution

    CachyOS - Arch Linux Based Distribution With Heavy Optimizations & Multi-Architectures For Ultimate Desktop Experience Filesystems: - btrfs - zfs - ext4 - xfs - f2fs Our installer will auto detect which micro architecture your machine got, if x86-64-v3 or x86-64-v4 is detected it will automatically use the optimized packages, which is around a 10 % performance improvement. Desktop Environments: - KDE - CuteFish - i3 - Gnome - Openbox - Wayfire - Xfce - LXQT - bspwm All packages are compiled with Full LTO and other optimization flags. Depending on the march your cpu have it is compiled against x86-64, x86-64-v3 or x86-64-v4. For the Desktop Environment we provide basic theming. In CachyOS-Hello can be also security related packages enabled, like: DNScrypt-proxy Firejail apparmor Security and Performance! https://discord.gg/qJqj94uFwE https://t.me/+zCzPX4cAFjk1MTY
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    Downloads: 6,247 This Week
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  • 3
    deepin
    deepin is a Debian-based distribution that aims to provide an elegant, user-friendly and reliable operating system. It does not only include the best the open source world has to offer, but it has also created its own desktop environment called DDE or Deepin Desktop Environment which is based on the Qt 5 toolkit. Deepin focuses much of its attention on intuitive design. Its home-grown applications, like Deepin Software Centre, DMusic and DPlayer are tailored to the average user. Being easy to install and use, deepin can be a good Windows alternative for office and home use.
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    Downloads: 1,398 This Week
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  • 4
    Arrow OS

    Arrow OS

    It is an AOSP based project with an aim of keeping things clean!

    ArrowOS is an AOSP based open source project started with the aim of keeping things simple, clean and neat, both for the Android system and users. We understand the pain of unnecessary and sometimes rarely used mods/features being shipped with custom roms nowadays which may end up causing battery drains and/or memory leaks. This is being strictly avoided on our side keeping everything to a bare minimum, delivering the stable performance all the time without destroying the AOSP interface. With users getting more used to tweaks and features, we added just the right stuff that will be actually USEFUL at the end of the day.
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    Downloads: 1,007 This Week
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  • Optimize every aspect of hiring with Greenhouse Recruiting Icon
    Optimize every aspect of hiring with Greenhouse Recruiting

    Hire for what’s next.

    What’s next for many of us is changing. Your company’s ability to hire great talent is as important as ever – so you’ll be ready for whatever’s ahead. Whether you need to scale your team quickly or improve your hiring process, Greenhouse gives you the right technology, know-how and support to take on what’s next.
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  • 5
    Ultimate Edition

    Ultimate Edition

    An Ubuntu remix for both new and experienced Linux sophisticates

    Ultimate Edition Linux, previously "Ubuntu Ultimate Edition". We cater to a large base of *nix users including, but certainly not limited to gamers & low resource computers. We have a Ultimate Edition for virtually any user.
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    Downloads: 1,339 This Week
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  • 6
    RichARCH

    RichARCH

    Creating a Rich experience to ARCH

    RichARCH is designed to be a Quick Simpler Path to Arch Linux including kickstart like automation features and Hyprland ricing options. Just one command to start the latest complete installer for Arch. One goal of the project is to only use packages in the basic Arch Linux repos by default with the option to install some non-standard packages. Our hope is that this will help to make Arch Linux more approachable to individual and corporate users. Details and installation info can be found at: https://download.sf.net/richarch/InstallAndInfo.pdf or https://sites.google.com/view/richarch Supports - AMD / Nvidia drivers - Fully automated installs - LVM storage setup options - Multiple storage formats, including: BTRFS, EXT4, XFS - GUI Environments: Budgie, Cinnamon, Cosmic, Cutefish, Enlightenment, Gnome, Hyprland, KDE, LXDE, LXQT, Mate, Niri, Omarchy, River, Sway, XFCE - Install Profiles (like HyprVibe, SecOps, Workstation, Server, Omarchy, Kool's Dots)
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    Downloads: 882 This Week
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  • 7
    Lingmo OS
    Lingmo GNU/Linux (Lingmo OS) is a desktop based Linux operating system developed based on the open-source Debian kernel and adapted to the amd64 architecture. It has a beautiful desktop environment, software that is compatible with the desktop environment, and a unified UI style. The goal of Lingmo GNU/Linux is to provide users with a luxurious and practical desktop environment as well as a smooth experience on low performance hardware.
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    Downloads: 747 This Week
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  • 8
    Sandboxie

    Sandboxie

    Sandboxie Plus & Classic

    Sandboxie (and its enhanced fork Sandboxie Plus) is an open-source sandboxing tool for Windows NT-based systems. It creates isolated virtual environments in which applications can run safely without permanently modifying the system, ideal for testing untrusted software. Sandboxie Classic has the old no longer developed MFC-based UI, hence it lacks native interface support for Plus features. Although some of the missing features can be configured manually in the Sandboxie.ini configuration file or even replaced with custom scripts, the Classic edition is not recommended for users who want to explore the latest security options. A completely different token creation mechanism from Sandboxie's pre-open-source version makes sandboxes more independent in the system.
    Downloads: 45 This Week
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  • 9

    Kernelloader

    Run Linux on the Playstation 2

    Kernelloader is a free bootloader for PS2 Linux and other Playstation 2 operating systems. Loading can be done by "Action Replay Media Player", by "memory card exploit", by "FMCB" or any other homebrew loading method. If you downloaded the latest Linux Live DVD, you need to run the online updater to be able to play Youtube videos.
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    Downloads: 193 This Week
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  • Fax.Cloud delivers encrypted, point-to-point faxing with guaranteed delivery and built-in audit trails Icon
    Fax.Cloud delivers encrypted, point-to-point faxing with guaranteed delivery and built-in audit trails

    For organizations in regulated industries needing a solution to replace traditional fax infrastructure and integrate with email or online portals

    Unlike email or file-sharing tools, Fax.Cloud doesn’t bounce around the internet, exposed and vulnerable. It’s direct, encrypted, and verified. You get delivery confirmation, audit trails, and peace of mind, without the spam filters, metadata leaks, or cyber threats.
    Learn More
  • 10
    ALG

    ALG

    A Fast, Offline, Graphical distribution based on Arch Linux

    October 2025 ISOs have been released! 3 new ISOs - PLASMA, GNOME, XFCE have been released. Thank you to all the members in the ALG community for their support.
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    Downloads: 608 This Week
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  • 11
    AROS Research Operating System
    The AROS Research Operating System is an effort to implement an Open Source and portable operating system that is compatible with AmigaOS(TM). Originally, it was meant as a direct reimplementation, but already has features not existing in AmigaOS.
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    Downloads: 128 This Week
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  • 12
    Robolinux

    Robolinux

    Announcing Robolinux Cinnamon 14.1

    Announcing The New Robolinux Series 14 Mate LTS - 2034 Robolinux is very pleased to announce a completely new 14.1 Mate privacy centered 1inux operating system you can download freely while also offering our users an optional 14+ advanced upgrade which comes with our Untracker and FAAST Boot along with one click popular privacy software installers like Tor and I2p, Wireshark and Bleachbit plus many more for a fair and reasonable price. Robolinux14.1-Mate is ideal for beginners and advanced users. We are proud that it comes with Enoch AI which is TOTALLY 100% PRIVATE, FREE, HONEST & UNCENSORED built into Robolinux Cinnamon 14.1 The Robolinux 14.1 version with rock solid Long Term Support through 2034! requires users to set secure boot in their BIOS. It is currently available in the Cinnamon desktop flavor. we will release series 14 Xfce version in the next two months.For more information please see Readme file. Warmest regards John Martinson Robolinux.org
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    Downloads: 113 This Week
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  • 13
    OpenWrt

    OpenWrt

    A Linux operating system targeting embedded devices

    OpenWrt Project is a Linux operating system targeting embedded devices. Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the application selection and configuration provided by the vendor and allows you to customize the device through the use of packages to suit any application. For developers, OpenWrt is the framework to build an application without having to build a complete firmware around it; for users this means the ability for full customization, to use the device in ways never envisioned.
    Downloads: 18 This Week
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  • 14
    IPCop Firewall

    IPCop Firewall

    Linux firewall distribution geared towards home and SOHO users.

    The IPCop Firewall is a Linux firewall distribution. It is geared towards home and SOHO users. The IPCop web-interface is very user-friendly and makes usage easy.
    Downloads: 65 This Week
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  • 15
    Endian Firewall Community
    Endian Firewall Community (EFW) is a "turn-key" linux security distribution that makes your system a full featured security appliance with Unified Threat Management (UTM) functionalities. The software has been designed for the best usability: very easy to install, use and manage and still greatly flexible. The feature suite includes stateful packet inspection firewall, application-level proxies for various protocols (HTTP, FTP, POP3, SMTP) with antivirus support, virus and spam-filtering for email traffic (POP and SMTP), content filtering of Web traffic and a "hassle free" VPN solution (based on both OpenVPN and IPsec).
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    Downloads: 362 This Week
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  • 16
    Br OS
    O nome Br OS tem dois significados, Br vem de Brasil, o país de origem do sistema, OS é Operating System, e a junção do nome fica Bros, que é uma gíria norte americana para Brothers, que significa Irmãos. Basicamente o que queremos dizer é que nosso sistema foi feito para unir pessoas, seja pelo conteúdo gerado por ele, ou pela comunidade que ele forma. Somos um só povo.
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    Downloads: 185 This Week
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  • 17
    DreamShell

    DreamShell

    Operating system for the Sega Dreamcast

    The Dreamshell is the operating system for the Sega Dreamcast based on the KallistiOS kernel. It has a dynamic loadable modular system and interface for creating applications with XML UI and both C/C++ and Lua scripts on. You can see examples in ready-made applications and modules, drivers for various devices, formats and interfaces. Examples for audio and video decoding, compression, packaging, binding, network, emulation, scripts and more. From hardcore low-level assembler to high-level applications. There is also large subproject is the ISO Loader, which contains emulation of BIOS system calls, CDDA playback, and VMU, also it can hooking interrupts for various SDKs and more.
    Downloads: 10 This Week
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  • 18
    BerserkArch

    BerserkArch

    A bleeding-edge, security-centric Arch-based Linux distribution.

    BerserkArch is a security-focused, performance-tuned Linux operating system (OS) based on Arch Linux, designed for developers, hackers, and technical users. A bleeding-edge, security-centric Arch-based Linux distribution crafted for hackers, developers, and nerds alike. Following the Arch Linux philosophy, it is designed to be highly customizable, allowing users to build their environment with only the components they need, rather than having a lot of pre-installed software like some other security distributions (e.g., Kali Linux). As an Arch-based distribution, it benefits from the rolling release model, providing users with the latest software versions and kernel updates. BerserkArch is a dist "designed to make you powerful" for specific use cases like reverse-engineering binaries and automating exploits, rather than being an easy-to-use distribution for general beginners.
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    Downloads: 238 This Week
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  • 19
    Berry Linux

    Berry Linux

    A lightweight flavor of Linux based on Fedora

    Berry Linux is a bootable CD Linux, automatic hardware detection. Berry Linux can be used as a Linux demo, educational CD, rescue system. It is not necessary to install anything on a hard disk.
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    Downloads: 129 This Week
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  • 20
    <<Hack|Track GNU/Linux

    <<Hack|Track GNU/Linux

    Distro Penetrasing Live System Burn to USB Flash Disk & Run.

    <<Hack|Track GNU/Linux is an open source operating system developed by the HTGL Project from Indonesia which provides penetration testing.
    Downloads: 115 This Week
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  • 21
    Ancient UNIX/BSD emulation on Windows
    Providing an easy to use platform for running Ancient UNIX & BSD on windows.
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    Downloads: 51 This Week
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  • 22
    WINIX OS

    WINIX OS

    A UNIX-style Operating System for the Waikato RISC Architecture

    Winix is an experimental Unix-like operating system kernel written in modern C++ with an emphasis on object-oriented design and code clarity. It is a pedagogical project exploring how kernel-level programming can be structured with C++ abstractions while maintaining low-level control. Winix supports basic system services such as file systems, process management, and a terminal interface, and is designed for booting on x86_64 hardware via QEMU. It serves as an accessible and unconventional approach to understanding operating systems.
    Downloads: 7 This Week
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  • 23
    NebiOS Alternative Mirror (Official)

    NebiOS Alternative Mirror (Official)

    An Ubuntu Linux-based OS that aims to end user.

    NebiOS is Ubuntu-based secure, privacy-focused universal OS for daily life, creativity, gaming & more. Official mirror - use if main site has download issues. Main site: https://nebios.org ⚠️ DON'T DOWNLOAD FROM UNKNOWN SOURCES! 🛡️ Privacy: NebiOS has no telemetry, no background data services, no tracking daemons, and cannot send any personal data without user action. Full policy: nebisoftware.com/legal/privacy.html === 🚀 NebiOS X out now! ⚠️ Note on Virtual Machines: NebiOS X is optimized and designed for real hardware performance and native GPU acceleration. Virtualization platforms (VMware, VirtualBox, GNOME Boxes, etc.) may show degraded graphics or system performance. For accurate testing, please install NebiOS X on physical hardware. === System Requirements and informations about before installation can be found at https://nebios.org/download (select your version for it)
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    Downloads: 101 This Week
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  • 24
    AlienVault OSSIM

    AlienVault OSSIM

    Open Source SIEM

    OSSIM, AlienVault’s Open Source Security Information and Event Management (SIEM) product, provides event collection, normalization and correlation. For more advanced functionality, AlienVault Unified Security Management (USM) builds on OSSIM with these additional capabilities: * Log management * Advanced threat detection with a continuously updated library of pre-built correlation rules * Actionable threat intelligence updates from AlienVault Labs Security Research Team * Rich analytics dashboards and data visualization
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    Downloads: 45 This Week
    Last Update:
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  • 25
    XNU

    XNU

    Legacy mirror of Darwin Kernel

    Darwin XNU is the hybrid kernel that powers Apple’s macOS, iOS, watchOS, and tvOS operating systems, forming the foundation of the Darwin open-source core. The name XNU stands for X is Not Unix, highlighting its origin as a combination of multiple kernel technologies—primarily the Mach microkernel from Carnegie Mellon University, integrated with substantial components from FreeBSD and Apple’s proprietary IOKit driver framework. This hybrid architecture merges the microkernel model’s message-passing flexibility with the monolithic performance and direct hardware control typical of Unix-like systems. XNU handles essential kernel responsibilities such as memory management, multitasking, interprocess communication (IPC), device I/O, system calls, security enforcement, and scheduling across both single and multi-core architectures.
    Downloads: 5 This Week
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