The Amiga OS was designed in a way that protected memory support was basically impossible. Message passing was used everywhere. How did it work? One process ("t

The Amiga OS was designed in a way that protected memory support was basically impossible. Message passing was used everywhere. How did it work? One process ("task", technically) sent a pointer to another, a small header with arbitrary data, which could contain anything, including other pointers. Processes would literally read and write each other's memory.