This final program (Mystery) is another demonstration of expanding the operating system - but I'm not going to tell you how it works (well, not yet anyway). The program creates an ARM code file from the DATA statements. You should then *RUN the resulting ARM code file.

The poser is this. By pressing RETURN a few times at the Supervisor prompt (*), you will see what the program does. However, the program takes no user memory whatsoever and does not claim any vectors. It makes one operating system call on start-up and then makes one call to the operating system each time you press RETURN . How does it work? Maybe if the Editor will let me, I'll tell you sometime. Please note that Arthur 1.2 is required as one of the new output routines is used (try different Modes and see what happens).