Efone is a distributed internet phone system. It features a voice sending/receiving client (an internet phone) and a central server (administered via the Web) where users' information (name, nick, password, current IP) is stored. It resembles a combination of ICQ and Internet phone.
DiaCanvas is a generalized version of the drawing canvas used by DIA. It extends some features used by DIA and adds new ones, while preserving as many of the original features as possible. This project is no longer actively maintained. It is suggested that you try DiaCanvas2 instead.
DinX (DinX is not X) is an experimental windowing system that performs clipping and drawing inside Linux kernel modules. This eliminates much context-switching between clients and the server, and makes the code small, simple and fast. It is aimed at small systems like Linux handhelds.
DeuTex is a wad composer for Doom, Heretic, Hexen and Strife. It can be used to extract the lumps of a wad and save them as individual files. Conversely, it can also build a wad from separate files. When extracting a lump to a file, it does not just copy the raw data, it converts it to an appropriate format (such as PPM for graphics, .au for samples, etc.). When it reads files for inclusion in pwads, it does the necessary reciprocal conversions. In addition, DeuTex has functions such as merging wads, etc.
dagrab is a command line driven tool for extracting digital audio from cd. It works great with IDE drives (and others type too if the kernel supports digital audio read for them, I think this does not include SCSI drives for now), and supports jitter correction, filters and audio post-processing,as well as CDDB to automatically name your files appropriately.
DAP is a comprehensive audio sample editing and processing suite. It currently supports AIFF and AIFF-C audio files, 8 or 16 bit resolution, and 1, 2 or 4 channels of audio data. The package offers comprehensive editing, playback, and recording facilities including full time stretch resampling, manual data editing, and a reasonably complete DSP processing suite.
csv2png and csv2jpeg use the GD library to plot time series data from a CSV file to either a PNG or a JPEG graphic. The program is deliberately simple, and is targeted at CGI applications. Originally written for RISC OS as csv2gif (see Acorn User, issue 215) the latest distribution builds on Linux as well.