Boots into many systems and GRUB2 ones!
amforth is an extendible interpreter on microcontrollers
freeRTOS for Arduino Uno, Goldilocks 1284p & Mega 2560
A microkernel-based multiserver operating system written from scratch.
An operating system written in RTL
My FreeDOS Floppy Disk Distribution
A Debug style tool for OS Free systems
Linux source-level kernel debugger
Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
A Haskell kernel for the Jupyter project
Kestrel is an experimental kernel runs on i386
C++ RTOS for my mustang ECU project
Nanux Kernel
Operating System in 512bytes.