This has certainly been an issue for me in the past. I have used various versions of DOS extenders to overcome the notorious 640K limit on PC's.

I have usually run these in DOS box, first on Windows 3.1, then Windows 95, 98 and NT.

What has been interesting is that the same compiled code behaved differently in the different sorts of DOS box, but that documentation about how the address space is handled in these different environments has proved difficult to find.

-- JohnFletcher