The single biggest extension to Win32 is the introduction of a flat 32-bit memory manager. Designed to supplement the 16-bit selector based memory manager (Local and Global functions), the new functions are much easier to use and document. Wherever possible equivalent capabilities have been preserved. There are some features in the 16-bit memory manager that have not been propagated into the 32-bit environment. This was only done when the feature was not portable or not required using the 32-bit model.