Fiwix is an operating system kernel based on the Unix architecture and fully focused on being Linux compatible. It is designed exclusively for educational purposes, so the kernel code is kept as simple as possible for the benefit of students. It runs on the 32-bit x86 hardware platform, and is compatible with a good base of existing GNU applications.
amforth is an extendible command interpreter for the Atmel AVR ATmega microcontroller family. It has a turnkey feature for embedded use as well. It does not depend on a host application. The command language is an almost compatible ANS94 forth with extensions. It needs less than 8KB code memory for the base system. It is written in assembly language and forth itself.
Tin Hat is a Linux distribution derived from hardened Gentoo. It aims to provide a very secure, stable, and fast desktop environment that lives purely in RAM. Tin Hat boots from CD, or optionally USB pen drive, but it is not a LiveCD in that it does not mount any file system from the boot device. Rather, Tin Hat employs a massive squashfs image which expands into tmpfs upon booting. This makes for long boot times, but remarkable speeds during human-computer interaction.
Toorox is a Linux live DVD based on Gentoo which starts as bootable media using KNOPPIX technology. It is designed for ease of use, with a simple control center and a hard disk installer. It contains many applications and uses KDE, GNOME, or XFCE as a working environment. A live USB pen drive image maker is also present on the desktop. It is multi-lingual and contains the unstable branch of Gentoo (x86 and amd64).
SONaFR is a small system based upon OpenBSD 4.1 and 5.1. Version 1.0 is a floppy version with router, NAT, and firewall capabilities. No hard disk or CD-ROM is necessary. The system boots off a floppy, and all you have to do is to configure it. It also has transparent firewall and bandwidth control capabilities. Version 2.0 has two bootable USB images (OpenBSD 5.1); one has 120 MB, and the other one 1 GB. It has DHCP, Midnight Commander (a Norton Commander clone), and various basic system tools.
DAPL (Direct Access Provider Library) is a transport-independent, platform-independent, high-performance API for using the remote direct memory access (RDMA) capabilities of modern interconnect technologies such as InfiniBand, the Virtual Interface Architecture, and iWARP. This is the reference implementation of that specification by the DAT Collaborative who maintain the DAPL API.
Mail2sh makes it possible to carry out shell commands by email. Email is sent to a particular user on your host and the commands will be carried out if the user and password given matches ones in /etc/passwd. Commands are executed with the user's privileges, and combined with a PGP module ensures a certain level of security for use. Note that the system is not natively encrypted, so use of an encryption mechanism is highly recommended for security reasons.
ipt_pkd is an iptables extension implementing port knock detection with SPA (single packet authorization). This project provides 3 parts: the kernel module ipt_pkd, the iptables user space module libipt_pkd.so, and a user space client knock program. For the knock packet, it uses a UDP packet sent to a random port that contains a SHA-256 of a timestamp, small header, random bytes, and a shared key. ipt_pkd checks the time window of the packet and does the SHA-256 to verify the packet. The shared key is never sent.