The 64 Studio Platform Development Kit (PDK) is a version control system for GNU/Linux distributions, allowing the creation and management of many different projects, based on Debian and Ubuntu sources. PDK is written in Python, and the source code is well commented and contains documented examples.
Agnix is a small, educational operating system kernel for i386, supporting 32-bit protected memory mode, paging, hardware switched tasks, memory tests, PCI bus, devices, PCI IRQ routing, RT timers, network protocols. It is available with all the source code and is fully compatible with the Linux kernel API.
Alpaca is a multitasking operating system for Z-80 based arcade hardware. It has been designed to run on both Pac-Man and Pengo based arcade machines, but can easily be ported to other machines with similar architectures. It supports four concurrently running processes, task switching, simple inter-process messaging, semaphores, and a basic window-based graphical interface.
CinayOS is a 64-bit operating system that was forked from Linux in order to develop a radically different approach to concurrency, SMP, and most other kernel subsystems. Its goals include a new caching infrastructure, easy software package management, and an OpenGL accelerated animation system.
DMAring demonstrates a novel generic network interface card driver architecture which works in hybrid interrupt-polling mode to deliver superior real-time performance on Linux, Red Hat Linux, or Linux-RTAI-LXRT (a real-time co-kernel for Linux with user level extension). Existing Linux drivers saturate the CPU at a much lower packet rate than the maximum possible wire line packet rate, but this driver allows vanilla network cards to be used for high speed packet capturing.