UAE (or "UNIX Amiga Emulator") is an open source program designed to run software written for the Amiga range of computers. Originally it was called the Unusable Amiga Emulator, due to it not even being able to boot, but that definition has since become obsolete.
UAE has been ported to many host operating systems, including Linux, MacOS, FreeBSD, MS-DOS, Windows, AmigaOS, and RISC OS.