amforth is an extendible interpreter on microcontrollers
AO RTOS is small real time OS based on Active Object concurrency model
A microkernel-based multiserver operating system written from scratch.
C-BIOS is an open source BIOS for MSX computers.
Message passing microkernel-based Operating System for ZX Spectrum +3e
UNIX/LINUX and legal homebrew software on the xbox360 gaming console
Real-Time Embedded Operating System
A Debug style tool for OS Free systems
A UNIX-like kernel for the i386 architecture
Run Linux on the Playstation 2
Run Linux on Windows or other OSes, natively.
CMAKE build enviroment for LPC2000 and LPC17xx Cortex MCUs
Neptune is a kernel and operating system for x86 PCs.
Embedded Real-Time Operating System (RTOS)