AO RTOS is small real time OS based on Active Object concurrency model
A cute and educational x86 OS
OS-9/6809 compatible operating system for Tandy CoCo and Dragon
an MS-DOS compatible OS, written in Pascal and i8086 assembly
Simplest kernel for cooperative multithreading
OS bootable from Linux,Windows and others partitions as auxiliary OS
Real time preemptive embedded multi-thread kernel
A Debug style tool for OS Free systems
A UNIX-like kernel for the i386 architecture
Mulithreading Arduno library
FreeMiNT is a free alternative OS kernel for Atari systems & clones
Written in pure ASM and Exode with cloud computing in mind.
This will be an operating system
An indie, hobby operating system
Neptune is a kernel and operating system for x86 PCs.
Embedded Operating System
A advanced graphical operating system.
An open source OS written in assembly.
Embedded Real-Time Operating System (RTOS)