Yes, indeed! You're spot on here. This is exactly what ithreads are and it's what perlthrtut means when it says:

In this model, each thread runs in its own Perl interpreter, and any data sharing between threads must be explicit. The user-level interface for ithreads uses the threads class.

That line tells us everything we need to know and it's why I quoted it in my above post. You've just elucidated what the documentation has said in that line in a much clearer and more explicit way.

"its own Perl interpreter" -- That tells us it's not really a thread, but a separate process as a real thread isn't a complete copy with its own interpreter but a unit of execution inside a process that shares address space with other unique units of execution.

"data sharing between threads must be explicit" -- And finally this tells us that they don't share address space and if you want shared data you must do it by some other means just as you would between any other 2 separate processes. Ie the standard way with ithreads is using the complex operations as you put it, ie IPC.

Also, again, please don't respond to me Browser. This response is not aimed at you, but for Juster and the general community. I've heard all you've had to say on the matter and I respectfully disagree, so please refrain from attacks on me.