XRoar is a Dragon 32, Dragon 64 and Tandy CoCo emulator for Unix, Linux, GP32, MacOS X and Windows32. It uses standard cassette images (“.cas”files) and virtual diskettes (“.vdk”files) but has its own snapshot format at the moment (no”.pak”file support). XRoar is Free Software, distributed under the terms of the GNU General Public Licence.

http://www.6809.org.uk/dragon/xroar.shtml