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.
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.
btfs can be used as /init for constructing a run-time environment before running the real init. It supports extracting compressed (*.cgz, *.cbz2) and uncompressed (*.co) cpios located on a compile-defined directory (/). Also, it creates a tmpfs filesystem as the new root, if / isn't one already and the purpose of the initramfs isn't for starting a system in another location (disk, network, etc.). That will allow for the data on / to be swapped to disk when swap devices are activated later.
ReVirt is part of the CoVirt project, which investigated on the use of virtual machines to provide security in an operating-system-independent manner to enable the security system to function independently from the guest operating system. ReVirt logs enough information to replay the entire intrusive sequence instruction-by-instruction so that a detailed observation on the attack can be documented. It includes a system called BackTracker that helps system administrators understand (and thereby recover from) an intrusion, by automatically identifying potential sequences of steps that occurred in an intrusion. Starting with a single detection point (e.g., a suspicious file), BackTracker identifies files and processes that could have affected that detection point and displays chains of events in a dependency graph.
EPOR is an extensible package organiser for Unix-like systems. It's written to trace filesystem changes (something being installed) and save this information in a simple text database (this, as any other provided feature, is customisable via the embedded Guile interpreter). Database entries contain information supplied by the command line (package name, version, etc.) and traced by filesystem changes (new directories, files, etc.). This is achieved using the "LD_PRELOAD method''.
Midge is a Linux OpenWrt-like mini-distribution for ADM5120 based routers, such as Edimax BR-6104K. It includes basic tools such as sh, dropbear_ssh, inetd, syslogd, telnet, netcat, tftp, wget, vi, and more. It uses the ipkg package system, which can be used for installing new software.