High Quality Content by WIKIPEDIA articles! Calamus is a desktop publishing application, built for Atari computer. The first version was released on July 1st, 1987 by the former German software company DMC GmbH. Calamus is still supported by its German owner company, invers Software, and also runs under a built-in and transparent Atari emulator on Windows, or on other platforms such as Mac OS 9 and Mac OS X, using any available TOS emulator.