ChibiOS/RT is a free and efficient RTOS designed for deeply embedded applications. It offers a comprehensive set of kernel primitives and supports many architectures: ARM7, Cortex-M0, Cortex-M3, Cortex-M4, PowerPC e200z, STM8, AVR, MSP430, ColdFire, H8S, x86.
JNode is a Java New Operating system Design Effort. JNode is a simple to use and install Java operating system for personal use on modern devices. Any java application runs on it, fast and safe. See our homepage for additional information.
Haiku is an open-source operating system currently in development designed from the ground up for desktop computing.
amforth is an extendible interpreter on microcontrollers
amforth is an extendable command interpreter running on AVR ATmega and TI MSP430 microcontrollers. Turnkey actions for fully autonomous operations are possible as well. The command language is close to the Forth 2012 standard.
colorForth is, in Chuck Moore's own words: "A dialect of Forth that uses color to replace punctuation. Includes its own operating system. Produces extremely compact programs. Instant compile from pre-parsed source."
uGNU/RTOS (literally "micro G'Noo RTOS") is an Open Source serial Real Time OS for microcontrollers (PIC, ATMEL).
fast single-privilege single-address-space preemptive-multithreading persistent data-centric secure multiuser operating system with safe-language and reconfigurable graphical interface
This was originally an OSdev group, but since as members disbanded, I'm continuing to provide various implemenatitions of software, hardware, operating systems, libraries, and some stuff related to math and physics.
FreeWPC is a software framework for writing new software for 1990's Bally/Williams pinball machines. The framework allows you to build your own ROM images, define your own game rules, incorporate dot matrix animations, design lamp shows, and so on.
K-OS is an open-source realtime-operating-system based on the OSEK/VDX standard aimed at compiler and microcontroller independence. Currently we support Motorola (Freescale) HC12/HCS12/HCS12X targets.
Agnix is an educational, network operating system kernel. It is ideal starting point to learn about operating systems. The main goal of the project is to provide a network kernel fully compatible with the Linux Kernel in the system call layer
Handix is the OS for the Aura line of simple, inexpensive palmtop-type handhelds, designed by this project.
AxionOS is (to be) a operating system for the Axion Prototype Computer (APC) which is basically a notebook. Currently the project is in its childhood, but the idea is simple - To create an intuitive, user-friendly operating system for the APC.
BOS – B.lu operating System, is an operating system dedicated to small microcontrollers and CPUs without MMU. Actually is dedicated to Texas Instruments MSP430 microcontrollers (it can be ported to other CPUs without great changes)
Barbux, the bearded people OS
An open source operating system for x86.
Codename Five is an operating system kernel, written as an experiment in learning assembler, written from scratch for x86. It is not (purposely) based on any previous operating system.
The D/OS Project aims to create a complete working operating system written in the D programming language.
DRAKE is a true homebrew game console that consists of specially crafted hardware, system software and games.
The Danber project aims to create an operating system where both Windows and Linux programs can be run: it is a Windows NT based kernel, but with UNIX user mode compatibility. Support for both PE and ELF executable formats.
The future of information technology will be based on controlling the flow of natural light. This project is an attempt to establish the code (or software) that will enable this to happen. It involves rewriting an OS from the ground up.
Fortress OS is an open source modern multitasking operating system. Intel IA-32 386 compatibility. Fortress is clean implemented from scratch. Fortress is still in early stage ( current state at the end of plan 2 ) and needs huge work.
A FOSS operating system that aims to meet NSA's TPEP TCB A1 evaluation standard while retaining application compatibility at minimal performance overhead.
LogoROS is new object-oriented operation system (currently in early development). See wiki page: https://sourceforge.net/apps/mediawiki/logoros/ and development blog: https://sourceforge.net/apps/wordpress/logoros/ for more info.
Exploring the possibilities of doing an Operating System completely different than all of the existing ones. Instead of basing it upon concepts that are 40 years old, design it from the ground up object oriented, peer-to-peer, and for security.