Notable Projects
This page maintains a list of mature hobby operating system projects considered to be notable. A hobby operating system is considered notable if it made some considerable progress (e.g. has had a full release, is self-hosting, has been reported on outside of the hobby OSdev world, etc.) or if it has achieved such notability within the operating system development community as a useful answer to the question, "I want to see what kind of operating systems you guys have built". It should have a relatively stable kernel and drivers, and some userspace applications. They are usually written by the members of this community, but not limited to.
Everyone is welcome to add their own projects to the regular Projects list of all hobbyist operating systems.
More advanced and successful alternative operating systems are listed at Advanced Projects page.
Notable Hobby Operating Systems
BareMetal
BareMetal is a 64-bit OS for x86-64 based computers. The OS is written entirely in Assembly while applications can be written in Assembly or C/C++. The two main purposes of BareMetal are for educational uses in learning low-level OS programming in 64-bit Assembly and to be used as a base for a high-speed data processing node. Source code is well documented and freely available. As of version 0.4.9 BareMetal OS officially supports multiple processors, memory management, and Ethernet communications.
Icon phone.png Ian Seyler (ian.seyler at returninfinity.com)
Icon license.png Open source (MIT)
Icon site.png http://www.returninfinity.com/
Icon floppy.png Unknown
Icon clock.png Abandoned
Ghost OS
A homemade operating system with a microkernel for the IA32 (x86) platform. The project is written in C++ and Assembly. Features: multiprocessor- & multitasking support, kernel API library, custom C library, ELF support, IPC (messages, signals, shared memory, pipes), VFS, window server & GUI with homemade toolkit, PS/2 keyboard & mouse driver, VESA video driver and more...
Icon phone.png Max Schlüssel ([email protected])
Icon license.png GPLv3
Icon site.png https://ghostkernel.org/
Icon floppy.png Unknown
Icon clock.png Active
Ironclad
Ironclad is a mostly formally verified hard real-time kernel written in SPARK and Ada. It is made to be 100% free software, free in the sense that it respects the user's freedom. It supports several architectures and features an advanced security model with features like Mandatory Access Control (MAC). The screenshot features Gloire, a distribution of Ironclad.
Icon phone.png [email protected]
Icon license.png GNU GPLv3
Icon site.png https://ironclad-os.org/
Icon floppy.png Unknown
Icon clock.png Active
KnightOS
Open-source operating system for Texas Instruments calculators. Features preemptive multitasking, memory management, etc. Written in z80 assembly.
Icon phone.png Drew DeVault (sir at cmpwn.com)
Icon license.png No License Information
Icon site.png http://knightos.org
Icon floppy.png Unknown
Icon clock.png Inactive (2021)
Managarm
Managarm is a 64-bit OS for x86-64. It’s written in C++ with a custom libc and a GNU like userland on top. Managarm’s main purpose is aiming for Linux compatibility while being completely asynchronous in terms of I/O. The OS is capable of running Weston and kmscon while effort is made into porting (a subset of) Xorg. Furthermore, Managarm supports many modern hardware devices, including USB 3 and has nearly full ACPI support.
Icon phone.png The official Managarm Discord server https://discord.gg/7WB6Ur3
Icon license.png Open source (MIT)
Icon site.png http://www.managarm.org
Icon floppy.png Unknown
Icon clock.png Active
MikeOS
MikeOS is an operating system for x86 PCs, written in assembly language. It is a learning tool to show how simple 16-bit, real-mode OSes work, with well-commented code and extensive documentation. It has a BASIC interpreter with 46 instructions, supports over 60 syscalls, could manage a serial terminal connection and output the sound through PC speaker. There is also a file manager, text editor, image viewer and some games
Icon phone.png Mike Saunders, okachi [at] gmail [dot] com
Icon license.png Open source
Icon site.png http://mikeos.sourceforge.net/
Icon floppy.png Unknown
Icon clock.png Discontinued
Pedigree
Monolithic OS with several backends supported - x86, x64, MIPS32, ARM and PowerPC. Kernel written in C++ with the obvious bits of ASM. Offers a reasonable amount of POSIX support and a tiling GUI and can run Apache, DOSBox, and various other common programs. Planned to also offer a native API alongside POSIX for Pedigree-specific applications.
Icon phone.png JamesM, bluecode, pcmattman, IRC freenode.net#pedigree
Icon license.png No License Information
Icon site.png http://www.pedigree-project.org/
Icon floppy.png Unknown
Icon clock.png Discontinued
RDOS
32-bit segmented operating system for 386 or higher processors. Support for USB (UHCI, OHCI, EHCI, XHCI) and USB 2 hubs, IDE and AHCI for discs, RTL8139 and RTL8169 for networks, and HD audio. It boots with EFI using GPT and BIOS using BIOS disc formats and supports FAT12, FAT16, and FAT32 filesystems. Supports both older CPUs with PIC & PIT and newer with APIC which also includes support for multicore operation. It has a full libc in the OpenWatcom project. OpenWatcom supports building segmented kernel drivers, and 32-bit flat applications, libraries, and DLLs. It has a command-line originally ported from FreeDos, and a GUI the includes widgets for labels, buttons, list boxes, and images (supporting PNG, JPEG, and BMP formats). In the debugging area, it supports remote debugging over TCP/IP from Windows using OpenWatcoms debugger that also can trace into the kernel, a kernel debugger, and a crash debugger. It runs on several thousand commercial installations as a controller and as a payment terminal.
Icon phone.png Leif Ekblad (leif at rdos.net)
Icon license.png No License Information
Icon site.png http://www.rdos.net/rdos/
Icon floppy.png Unknown
Icon clock.png Active
SeaOS
SeaOS is a hybrid kernel with loadable modules that supports ATA, AHCI, EXT2, ELF, and many other fancy acronyms. It has basic networking support, initial VT-x support, and is self-hosting with a fairly complete unix-like userland. Designed for simplicity.
Icon phone.png Daniel Bittman (danielbittman1 at gmail.com)
Icon license.png No License Information
Icon site.png http://dbittman.github.io/seaos
Icon floppy.png Unknown
Icon clock.png Inactive (2016)
SerenityOS
SerenityOS is a graphical Unix-like OS written in C++. It combines a 1990's style GUI with a modern CLI. Everything is from scratch, including a web browser with JavaScript and HTTPS support. A growing number of 3rd party packages are available as optional ports, including GCC, bash, vim, Python, SDL2, etc. You can watch videos of the system being developed on YouTube: https://www.youtube.com/c/AndreasKling.
Icon phone.png Andreas Kling, kling [at] serenityos [dot] org
Icon license.png Open source (BSD 2-clause)
Icon site.png https://github.com/SerenityOS/serenity
Icon floppy.png Unknown
Icon clock.png Active
skiftOS
skiftOS is a hobby operating system built for learning and fun targeting the x86 platform. It features a kernel named hjert, a graphical user interface with a compositing window manager, and familiar UNIX utilities.
Icon phone.png Nicolas Van Bossuyt, nicolas.van.bossuyt [at] skiftos [dot] org
Icon license.png Open source (MIT)
Icon site.png https://github.com/skiftOS/skift
Icon floppy.png Unknown
Icon clock.png Active
Sortix
Sortix is a small self-hosting operating-system aiming to be a clean and modern POSIX implementation. It is a hobbyist operating system written from scratch with its own base system, including kernel and standard library, as well as ports of third party software. It has a straightforward installer and can be developed under itself. Releases come with the source code in /src, ready for tinkering.
Icon phone.png sortie, https://sortix.org/
Icon license.png Open source (ISC)
Icon site.png https://sortix.org/
Icon floppy.png Unknown
Icon clock.png Active
TempleOS
TempleOS is a 64 bit lightweight OS with multitasking and multicore support, which is ring-0-only and works in a single address space. It provides the interface for communicating with God: the user has to choose a random number from the constantly changing sequences and then it is converted to the text interpretation. Whole OS with its' software has been single-handedly created during 15 years by Terry A Davis - who also developed a programming language called Holy C together with a special compiler for it. TempleOS supports the FAT32 and RedSea filesystems (the latter created by Terry) and also the file compression. It doesn't support the networking, partially for ideological reasons, but there are forks available with added functionality
Icon phone.png Terry A Davis, http://www.templeos.org
Icon license.png Open source (Public Domain)
Icon site.png http://templeos.org/
Icon floppy.png Unknown
Icon clock.png Discontinued
ToaruOS
64-bit modular kernel written in C. Supports pipes, shared memory, signals, POSIX-like VFS, threading, audio, IPv4. Heavy focus on advanced GUI, including a compositing window system.
Icon phone.png klange, #toaruos on irc.libera.chat
Icon license.png NCSA/University of Illinois License
Icon site.png http://toaruos.org/
Icon floppy.png Unknown
Icon clock.png Active
Visopsys
Visopsys (VISual OPerating SYStem) is an alternative operating system for PC-compatible computers, written "from scratch", and developed primarily by a single hobbyist programmer since 1997. Its primary "useful feature" is a reasonably functional partition management program - the ‘Disk Manager’, which can create, format, delete, resize, defragment, copy, and move partitions, and modify their attributes. It supports both DOS/MBR and UEFI partition tables. It can also copy hard disks, and has a simple and friendly graphical interface. A basic version can fit on a bootable floppy disk, or you can use the entire system from a ‘live’ CD/DVD
Icon phone.png https://visopsys.org/about/
Icon license.png Open source (GNU GPLv2)
Icon site.png http://visopsys.org/
Icon floppy.png Unknown
Icon clock.png Active
Vanadium OS
Vanadium OS is a multi-user Unix-like OS. i386, amd64. Fully protected mode. Memory, file and hardware protection. root and unprivileged users. GUI without X, modular kernel, and has a live floppy image with a single user mode! My homepage: http://www.durlej.net/contact ; project pages: http://www.durlej.net/v/ , http://www.durlej.net/nameless , https://github.com/p-durlej/newsys . One of the great features is that you can write C code and instantly compile it to execute
Icon phone.png Piotr Durlej, http://www.durlej.net/contact
Icon license.png Open source (BSD 2-clause)
Icon site.png https://github.com/p-durlej/newsys
Icon floppy.png Unknown
Icon clock.png Inactive (2018)