Originally Posted by Thorham
The OS can give a receiving task read-only privileges for the received message buffer. If the receiving task wants to reply to the message, it uses it's own buffer, and sends that pointer over. The task that receives the reply then also has read-only privileges for the received buffer.
Yes, sounds like memory protection. Are you depending on other software respecting that read-only status, or are you looking to enforce it? Enforcing it costs performance, so you're already at a disadvantage performance-wise compared to Amiga OS. If you're expecting software to be well behaved and respect memory flags, then you're basically no different to Amiga OS right now.