The ultimate DOS XMS memory manager
cMIPS - an FPGA ready VHDL model for 5-stage pipeline, MIPS32r2 core
A low-power ISA design and simulator for a 2010 IEEE competition
Crosos is a SubLinux Distribution
A 65C02 Emulator for Microchip PIC24/33
Gameboy Advance emulator for Android phones
Mayax is a 32-bit hobby OS with windows style GUI.
Quantum Leaps (QPC) DPP example with LWIP on STM3220G eval board
NES emulator for Android phones
A rethinking of the Operating System Ecosystem.
Gameboy and Gameboy Color emulator for Android phones
z390 Portable Mainframe Assembler and Emulator
an os for x86 computers based on mikeos
PrimOS is a 32bit multi-task OS, which is still under development.