L4Linux runs in user-mode on top of the µ-kernel, side-by-side with other µ-kernel applications such as real-time components. It is binary-compatible with the normal Linux/x86 kernel and can be used with any PC-based Linux distribution. L4Linux is part of the Dresden Real-Time Operating Systems Project (DROPS) aiming at the support of applications with Quality of Service requirements.
lcdmod is a kernel module for using HD44780 compatible LCD displays connected to the parallel port. The driver is based on a vt52 display, so output from commands can simply be echoed to the device file. It uses fast 8 bit mode, and supports user defined fonts and multiple wiring schemes.
leJOS is a Java-based replacement firmware (OS) for LEGO Mindstorms programmable bricks, including RCX and NXT. It supports threads, exceptions, synchronization, floating point arithmetic, strings, and so on, but there is no garbage collection yet. It is also designed to be portable to other small devices.
The libcomprex library transparently handles automatic compression and decompression of files and archives located locally, online, or even in other compressed archives. The API is similar to C's built-in file access functions, which provides a smooth transition to libcomprex. libcomprex can also open uncompressed files, making it a good replacement for the native file access functions.