DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
uClibc (µClibc) is a C library for developing embedded Linux systems. It is much smaller then the GNU C Library, but nearly all applications supported by glibc also work perfectly with uClibc. Porting applications from glibc to uClibc typically involves just recompiling the source code. uClibc even supports shared libraries and threading. It currently runs on standard Linux and MMU-less Linux (also known as µClinux) systems with support for ARM, i386, h8300, m68k, MIPS, mipsel, PowerPC, SH, SPARC, and v850 processors.
SOSSE (Simple Operating System for Smartcard Education) is a free smart card operating system. It is implemented in C and assembler for the Atmel AVR smart cards (Funcard, PinkCard, Jupiter). The aim of this project is to provide something like Linux for smart cards, which is a market full of NDAs. SOSSE should make it possible to learn about smart cards, and to implement and test your own ideas.
WISP-Dist is a modular embedded Linux distribution for wireless routers, but can be used for other purposes as well. The entire system fits in 8 MB flash/16 MB RAM. Highlights include an easy-to-use menu interface, commandline access, an Access Point mode (on selected cards), OSPF/RIPv2, bandwidth shaping, NAT, Layer 3 (proxy arp) bridging, and other goodies. The goal is to create an open, customizable, and easy-to-use solution for wireless routers.
Contiki is an open source, highly portable, networked, multi-tasking operating system for the Internet of Things. Contiki includes a multitasking kernel, a TCP/IP stack and a set of application programs, and a low-power radio communication stack. It is written in C and designed to be very small: it runs comfortably in a few kilobytes of RAM.
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.
Thinux is a thin-client server on a live CD. It boots a network of diskless computers to automatically start an application such as a Web browser. Each thin client machine acts as a cluster node to share its processing and memory resources with each other to take the load off the server. It is a turnkey solution that does not change nor rely on your existing systems to run. By booting from a removable CD, it does not lock-in the user so it is convenient to test. It is ideal for any organizations that require large deployment of software automatically and cost effectively.