The source for the Linux kernel used in Windows Subsystem for Linux 2
Hobby operating system, bootloader, kernel, drivers, C library
Real-Time Embedded Frameworks based on active objects & state machines
freeRTOS for Arduino Uno, Goldilocks 1284p & Mega 2560
Software development for 4Mb portable, using Z80 CPU and AA batteries
A cute and educational x86 OS
A microkernel-based multiserver operating system written from scratch.
The classic RPL programming language reimplemented and reimagined.
OS bootable from Linux,Windows and others partitions as auxiliary OS
Open-source RTOS and Embedded Systems Toolkit for C++ and C
PRTOS is a simple, compact preemptive RTOS for embedded systems
ext2/3/4 library for microcontrollers
A UNIX-like kernel for the i386 architecture
Mulithreading Arduno library
Run Linux on Windows or other OSes, natively.
Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
A Development Framework for Coldfire
Small real time operating system for AVR and ARM microcontrollers
A Simple 'IDE'A for Linux Kernel Developers
A new OS
Custom firmware and IDE for the VEX Cortex Microcontroller
Crosos is a SubLinux Distribution
Mayax is a 32-bit hobby OS with windows style GUI.