In hindsight. I wasn’t clear, but my comment was triggered by > I’ve not seen any references to locking handles so they don’t move during operations. That doe

In hindsight. I wasn’t clear, but my comment was triggered by > I’ve not seen any references to locking handles so they don’t move during operations. That doesn’t make sense to me. If memory blocks never move, why go through the trouble and performance hit of double indirection? That led to me guessing the MMU was involved, but it may not have been. The Lisa did have movable memory blocks, though, at least in LisaWrite. https://www.folklore.org/StoryView.py?project=Macintosh&story=Hungarian.txt https://www.folklore.org/StoryView.py?project=Macintosh&stor...: “The Lisa word processor team had developed a memory manager with relocatable blocks, accessing memory blocks indirectly through "handles", so the blocks could be moved as necessary to reduce fragmentation.”