How can executables work when being thrown into different addresses on 68000 ?

[commodorejohn]

The executable file format, IIRC, provides a list of addresses that need to be adjusted for relocation. Also, the 68000 has a sizable range for relative branching (+/- 32KB) and highly orthogonal addressing modes, so it's entirely possible to construct code that doesn't use fixed addresses at all.

[commodorejohn]

Yes, PPC has an MMU - but everything in the Amiga system architecture is designed around a flat global memory map. Message-passing is as simple as handing over a pointer to the message to the receiving process. So introducing hardware relocation or other MMU concepts would either require an insane amount of bookkeeping on the part of the OS, or throw everything into chaos.