xP provides an intuitive, high quality, graphical (X11) user interface to the University of Washington's PINE Messaging System. xP aims to provide an interface that is welcoming and easy to use for the new user, while still retaining the look, feel and key commands of PINE for the experienced user.
Zip is a compression and file packaging utility for Unix, VMS, DOS, OS/2, Windows 9x/NT, Amiga, Atari, Macintosh, BeOS, SMS/QDOS, MVS, VM/CMS, and others. It is analogous to a combination of the Unix commands tar(1) and compress(1) and is compatible with PKWARE's PKZIP and Nico Mak's WinZip. It's part of the Info-ZIP project.
ZooLib allows one to write a single set of C++ sources which can be compiled into native executables for Mac OS, Windows, BeOS, or POSIX-compliant systems that use the X Window system (such as Linux). Zoolib provides a GUI toolkit with a uniquely flexible layout system. It also provides a single-file database format, TCP networking, and extensive debugging support. ZooLib applications are multithreaded. ZooLib requires only minimal support from the underlying OS and platform GUI layer, and thus could be ported to a completely new platform without too much difficulty. ZooLib is fully production quality on Windows and MacOS, completely implemented but untested on BeOS, and not yet complete on POSIX. Please note that the sources from the "demo" branch are also required to build ZooLib or to get started writing your own ZooLib applications.
ZThread is an advanced object-oriented threading and synchronization library, implemented in C++ for POSIX, MacOS, and Win32 systems. It provides an excellent and powerful abstraction from native threads. It includes interruptible thread objects and several other synchronization control objects.
Audacity is a cross-platform multitrack audio editor. It allows you to record sounds directly or to import Ogg, WAV, AIFF, AU, IRCAM, or MP3 files. It features a few simple effects, all of the editing features you should need, and unlimited undo. The audio I/O uses PortAudio, which fully supports OSS, Mac OS X CoreAudio, and Windows WMME, and can be compiled with support for ALSA and Jack.
UDI, the Uniform Driver Interface, is a well-documented interface between a driver module and the executing OS. It provides source portability across OSes and binary portability within a processor ABI. It also provides modern driver features like instance independence, high scalability, and physical location transparency. The Reference Source provides an initial implementation of UDI for Linux, SCO UnixWare, SCO OpenServer, and other OSes.