Mercat is a light-weight, cross platform programming language. It is garbage collected and self hosting and produces portable byte-compiled binaries that can be executed on any platform with the appropriate interpreter. Interpreters are available for Linux, DOS (32-bit) and DOS (16-bit) and the interpreter source should be easily compilable for other platforms.
AA-lib is a low level gfx library just as many other libraries are. The main difference is that AA-lib does not require graphics device. In fact, there is no graphical output possible. AA-lib replaces those old-fashioned output methods with a powerful ASCII art renderer. The API is designed to be similar to other graphics libraries.
LibDsk is a library that attempts to create uniform functions for accessing floppy drives, raw "dd" disk images, and disk image files in various emulator formats. Its intended use is for emulator authors; it also includes some sample tools to read sectors from discs in CP/M, DOS, and Acorn formats. There is special-case code for direct access to the floppy controller under Linux, and to access the floppy driver under Windows. Java (JNI) bindings are included.
dbf is an easy-to-use command line tool to show and convert the content of dBASE III, IV, and 5.0 files, as well as of FoxBase and Visual FoxPro. It reads xBASE-compatible databases and prints the content to the screen or converts it to comma-separated (*.csv) files which can be opened in Excel, StarOffice, and most other spread sheets. It can also be used to show some statistics about the content.