MESS SVN r22512
atom driver
atom_windows.rom (K. van Oss)
atom_gags.rom (Gerrit Hillebrand)
In principle seems the cartridge slot(s) to work.
AW is the ROM-based command to show version number of the ROM.


GAGS is the ROM-based command to show version number of the ROM.


INV is the ROM-based (GAGS) command to invert the screen in each graphics mode.


Conclusion: You need to know the ROM-related and supported commands in order to work.