Comment by tgv
1 month ago
The original MacOS lacked memory protection too. It had cooperative multi-tasking, starting at version 7. Before that, the only thing that could be launched next to the main application were "desk accessories", which were a bit of a pain to write, as they had to stay out of harm's way.
MultiFinder existed before System 7. It was just optional.
MultiFinder was introduced in System 5.
Before that, there was Switcher - not a multitasker, but did keep multiple (non-DA) applications in memory at the same time.