Building and running ancient Linux on Windows
amforth is an extendible interpreter on microcontrollers
AO RTOS is small real time OS based on Active Object concurrency model
Software development for 4Mb portable, using Z80 CPU and AA batteries
UNIX/LINUX and legal homebrew software on the xbox360 gaming console
RTOS for Secure, Safe and Real-Time Systems
FreeDOS is an open source DOS-compatible operating system
A UNIX-like kernel for the i386 architecture
a very fast full system simulator
Custom firmware and IDE for the VEX Cortex Microcontroller
Project has been move to https://github.com/ciaa/Firmware
operating system for Intel 8086 / 8088
Tarbox OS is a minimalistic 16 bit OS being developed in x86 Assembly.