I always thought of Mac emulators as mid-level "shell" software. I know they're a lot more complicated than the old DOS GUIs, back in the day, but AFAIK or understand them, they go just deep enough into the machine level code to run a non-native OS & its software apps.

Interesting question, does anyone know of any 8 bit + software emulators that can do hardware calls across the host's expansion bus? :?: