From the forum FAQ:
Q: What is ProjectOZ?
A: ProjectOZ is an alternative to Unix-based simulators for exploring operating system principles. Based on the SPACE OS research at UC Santa Barbara, ProjectOZ builds simple, clean user-mode abstractions for the CPU, MMU, trap mechanism, and physical memory using the native NT layer of Windows, and then layers on top a simplified kernel-based OS which students can modify to perform experiments. Because there is an actual OS underneath handling the hardware details as opposed to a simulator, students have more time to explore kernels at the algorithm and data structure level. ProjectOZ supports experiments with multiprocessors and multicomputers on a student's single uniprocessor PC.