License: GPLv3


ExectOS aims to be a stable and flexible, general purpose operating system written from scratch. It is designed to be modular, maintainable and compatible with existing software. It implements a brand new XT architecture and features own native application interface. On the backend, it contains a powerful driver model between device drivers and the kernel, that enables kernel level components to be upgraded without a need to recompile all drivers.


License: BSD 2-Clause


A graphical Unix-like operating system for desktop computers! SerenityOS is a love letter to ’90s user interfaces with a custom Unix-like core. It flatters with sincerity by stealing beautiful ideas from various other systems. Roughly speaking, the goal is a marriage between the aesthetic of late-1990s productivity software and the power-user accessibility of late-2000s *nix.


License: GPLv2


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. Visopsys is free software and the source code is available under the terms of the GNU General Public License. The libraries and header files are licensed under the terms of the GNU Lesser General Public License.


License: NCSA


ToaruOS is a “complete” operating system for x86-64 PCs and experimental support for ARMv8. While many independent, hobby, and research OSes aim to experiment with new designs, ToaruOS is intended as an educational resource, providing a representative microcosm of functionality found in major desktop operating systems. The OS includes a kernel, bootloader, dynamic shared object linker, C standard library, its own composited windowing system, a dynamic bytecode-compiled programming language, advanced code editor, and dozens of other utilities and example applications.