Ngspice is a mixed-level/mixed-signal circuit simulator based on three open source software packages: Spice3f5, Cider1b1, and Xspice. Spice3 is the most famous and widely used circuit simulator. Cider is mixed-level simulator that includes Spice3f5 and adds DSIM, a device simulator. Cider couples the circuit level simulator to the device simulator to provide greater simulation accuracy (at the expense of greater simulation time). Xspice is an extension to Spice3 that provides code modeling support and simulation of digital components through an embedded event driven algorithm.
Over5 is a program for transferring between c64/vic20 machines and Amiga/PC/UNIX boxes. It supports serial transfer at 38400 bps using only a RS-232 level converter and a 3-line standard nullmodem cable. No special serialport chips are needed. Source code is included. It features read/write/execute memory, filecopy with wildcards, read/write raw disk, read/write ZIPCODE archive, the ability to use the Amiga/PC/UNIX box as a harddisk server ($0801-$f600), builtin diskturbo, and a fast basic bootstrap for most cbm 8-bitters.
Palm-Strip-Export is a utility to export your legacy PalmOS Strip databases to simple CSV files. Once your databases are exported you can print them, open them in Excel, or import them into a separate program. Most importantly, these export files will be directly importable to the iPhone when the desktop sync tool is released. This exporter only works with Palm Strip 2.0 databases.
pngquant is a batch conversion utility to quantize and dither truecolor PNG images, especially those with a full alpha channel, down to "RGBA-palette" PNGs (i.e., PLTE + tRNS in PNG parlance). Such images are usually two to four times smaller than the full 32-bit versions, and partial transparency is preserved quite nicely. This makes pngquant especially useful both for Web sites and for PlayStation 2 development, where one of the texture formats is RGBA-palette-based (though not PNG-compressed).
The pnmtopng package contains the official pnmtopng and pngtopnm utilities for use with the rest of the PBMplus/NetPBM suite. They are among the best PNG-supporting applications available, with automatic detection of grayscale or palette images and excellent heuristics for creating the smallest possible PNG images.
These are the demo programs that accompany O'Reilly's "PNG: The Definitive Guide." rpng is a simple file viewer with the ability to set a background color when displaying transparent PNGs. rpng2 is a progressive PNG viewer, designed to work like a web browser (though it contains no network code); it can generate a background image when displaying transparent PNGs. wpng is a simple converter from NetPBM to PNG format; in most respects it is much more limited than pnmtopng, but it supports interactive entry of PNG text annotations and will generate noninterlaced PNGs on the fly (rather than buffering the entire image first like pnmtopng). The viewers include simple front ends for both X and Win32; the converter is a command-line app that compiles on Unix, Windows, and probably other platforms.