Nuttx is a real-time embedded operating system (RTOS). It has a small footprint that is usable in micro-controller environments. It is fully scalable from tiny (8-bit) to moderate embedded (32-bit) systems. It also aims to be fully compliant to standards, to be fully real time, and to be totally open.
LPAR2RRD makes historical, future trends and nearly "realtime" CPU utilization graphs of LPARs and shared CPU usage of IBM Power servers. It collects complete physical and logical configuration of all servers/LPARs. It is agent-less (it gets everything from the HMC/SDMC or IVM). It supports all kinds of logical partitions (AIX/AS400/Linux/VIOS).
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.
GeeXboX is a standalone media player Linux distribution, similar to MoviX. It's a small bootable CD that allows you to play your favorite video (DivX, XviD, H.264, MPEG 1/2, VCD, DVD, OggMedia, Windows Media, RealMedia, etc.) and audio (MP3, Audio CD, Ogg Vorbis, FLAC, MPC, etc.) files. It also supports networking, and is able to play media from Windows/Samba share, NFS, UPnP A/V Media Servers, RTP/RTSP servers, or SHOUTcast. It supports TV-out, TV tuners, DVB cards, and WiFi cards. It is based on MPlayer, and can be used on any x86, x86_64, or PowerPC computer. It's easy to modify the source to build your own GeeXboX or use an alternative boot method.
SchilliX is an OpenSolaris-based live CD and distribution that is intended to help people discover OpenSolaris. When installed on a hard drive, it also allows developers to develop and compile code in a pure OpenSolaris environment. SchilliX tries to be as Sun Solaris compatible as possible and to be the optimum development platform for Solaris and OpenSolaris.
HelenOS is a microkernel-based multiserver operating system designed from scratch. By decomposing the operating system functionality into tens of isolated but intensively communicating userspace servers, it provides a computing environment that has several virtues such as flexibility, increased robustness, well defined explicit interfaces, and smaller complexity of individual components. HelenOS does not aim to be another clone of Unix or some other legacy system and is not POSIX-compliant (even though it may seem POSIX-similar at times). Instead, the goal has been to design it according to what is the most elegant and right thing to do. What makes HelenOS unique among the other multiserver operating systems is its multiplatform and multiprocessor microkernel. It will run on seven different processor architectures ranging from a 32-bit uniprocessor little-endian ARMv4 to a 64-bit multicore big-endian UltraSPARC T1.
BitRock InstallBuilder allows you to create easy-to-use multiplatform installers for Linux (x86/PPC/s390/x86_64/Itanium), Windows, Mac OS X, FreeBSD, OpenBSD, Solaris (x86/Sparc), IRIX, AIX, and HP-UX applications. The generated application installers have a native look-and-feel and no external dependencies, and can be run in GUI, text, and unattended modes. In addition to self-contained installers, the installation tool is also able to generate standalone RPM packages.
UNIXem is a small and simple library that provides emulation of several popular Unix API functions on the Win32 platform. Its primary purpose is to assist Win32 programmers who are porting to Unix or are writing multi-platform code. API functions include opendir/readdir/closedir, glob/globfree, readv/writev, pathconf/realpath, mmap/munmap/msync, dlopen/dlclose/dlsym/dlerror, gettimeofday, and getpagesize.