Originally Posted by Megol
Don't forget Mac OS. It used a "handle" mechanism for tracking (essentially a indirection of pointers). I would be surprised if Lisa didn't use the same mechanism.
I've never looked at the Lisa API myself, but I wouldn't bet on it. The Resource Manager and its associated approach to memory management were almost entirely the work of Mac Team member Bruce Horn (a Xerox alumnus who also designed the Finder,) and from his account
it doesn't sound like the kind of thing most other people at Apple were doing, at the time.