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.

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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: 5,002 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: 5,358 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: 2,481 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: 876 This Week
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  • 5
    RichARCH

    RichARCH

    Your concierge creating a Rich experience to Arch

    RichARCH is designed to be a Quick Simpler Path to Arch with automation and ricing options. Just one command to start the latest complete installer for Arch. One goal 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. More info at: https://download.sf.net/richarch/InstallAndInfo.pdf https://sourceforge.net/projects/richarch/files https://sites.google.com/view/richarch Supports: - AMD/Nvidia drivers - Fully automated installs, simple helpful menu structure - Extra software options from multiple stable repos - Storage options, including: BTRFS/EXT4/XFS/LVM - GUIs: Budgie/Cinnamon/Cosmic/Cutefish/Enlightenment/Gnome/Hyprland/KDE/LXDE/LXQT/Mate/Niri/River/Sway/XFCE - Profiles: SecOps/Server/Omarchy/HyprVibe/KoolsDots/Shell Ninja/TheBlackDon
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    Downloads: 1,004 This Week
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  • 6
    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: 351 This Week
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  • 7
    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: 49 This Week
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  • 8
    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: 268 This Week
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  • 9
    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: 486 This Week
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  • 10

    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: 144 This Week
    Last Update:
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  • 11
    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: 25 This Week
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  • 12
    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.
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    Downloads: 108 This Week
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  • 13
    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: 566 This Week
    Last Update:
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  • 14
    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: 21 This Week
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  • 15
    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
    Leader badge
    Downloads: 100 This Week
    Last Update:
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  • 16
    Ancient UNIX/BSD emulation on Windows
    Providing an easy to use platform for running Ancient UNIX & BSD on windows.
    Leader badge
    Downloads: 93 This Week
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  • 17
    Pony OS

    Pony OS

    My Little Unix: Kernels are Magic

    ponyos is a lightweight, UNIX-like operating system developed as a personal hobby project by the creator of ToaruOS. It features a monolithic kernel written in C and aims for a POSIX-compliant environment with a built-from-scratch userland. ponyos includes a graphical interface, dynamic linker, shared libraries, and a package manager. It’s designed for fun, experimentation, and as a platform to learn and play with operating system internals, with surprisingly advanced features given its hobbyist origin.
    Downloads: 12 This Week
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  • 18

    WANem - Wide Area Network Emulator

    Wide Area Network Emulator

    WANem is a wide area network emulator. It supports various features such a bandwidth limitation, latency, packet loss, network disconnection among other wide area network characteristics.
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    Downloads: 91 This Week
    Last Update:
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  • 19
    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: 300 This Week
    Last Update:
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  • 20
    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: 74 This Week
    Last Update:
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  • 21
    <<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.
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    Downloads: 150 This Week
    Last Update:
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  • 22
    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: 144 This Week
    Last Update:
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  • 23
    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: 97 This Week
    Last Update:
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  • 24
    EasyPeasy
    EasyPeasy is a lightweight operating system for netbooks, designed for the Internet and low power consumption.
    Downloads: 35 This Week
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  • 25
    CoolPotOS

    CoolPotOS

    CoolPotOS for ia32 / amd64

    CoolPotOS is a small, hobbyist operating system designed to be minimal and educational, offering the most basic kernel capabilities while remaining accessible to beginners. Written in C and Assembly, it focuses on bootstrapping, kernel entry, and simple console output. Though in early stages, CoolPotOS showcases the boot process, memory segmentation, and essential CPU features, serving as a great learning resource for those new to operating system internals.
    Downloads: 6 This Week
    Last Update:
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