[Coco] Does NitrOS9 limit apps to =<64K?

[David J Bush]

I'm not talking about the size of the object code. I mean
giving the app access to as much of the full 512K (or 2M)
as possible, for data.

Is it possible for an app to send a request to Nitros9
to gain at least partial access to the MMU? Something like
"I want to use N 8K pages of physical memory" and Nitros9
could respond with "Here they are, you can refer to them
as pages 0 to N-1" Maybe this request would occur when
the module for that app is loaded. I suppose the app would
also have to request K logical pages as well, and the OS
would respond with "You may directly address this list of
logical pages." Then during execution the app could say
"I want logical page i to point to physical page j". This
runs a bit contrary to the idea of OS9 being able to move
modules around in memory any way it wants, but the 64K
limit on app size really puts a crimp on capabilities.

Maybe it would be simpler for a file to be executable by
OS9 (position-independent code, etc.) but the moment it
starts running, it takes control of the machine, with its
own disk driver, printer driver, etc. It takes over the
MMU and trashes OS9 and any apps that were loaded into RAM.
Then, when you exit this program, OS9 will automatically
reboot.

One possible example would be a text editor or word 
processor that could hold very large documents in RAM all
at once. This is just a CoCo, after all. It's not like
you had some crucial background task you need to keep
running while this app is running. One big job at a time
is all you really need to be able to do. Multitasking is
a fantastic capability for an OS on such a small machine,
but just because you can do something doesn't mean you
have to.

Thanks for your time.

David