An external Memory Management Unit (MMU) can help enforce access control based on privilege levels, preventing User mode programs from modifying system memory. It also aids in virtual memory management and multitasking. This separation helps protect the system from user program errors and malicious activities.
Even on systems like the Atari ST and Amiga 500 that lack an MMU, the privilege modes prevent user programs from interfering with the interrupt system.
== Instruction Set ==