This process simplifies things quite a bit, as the organization of the unstable tree can change based upon changes to the pages (recall that pages in the unstable tree are not write protected).

In the days before Windows, this is a very important function, but the 32-bit "protected mode" software does not use BIOS, therefore the use of this feature and even less.

NTLDR loads the basic memory configuration and switches to 32-bit mode (protected mode). NTLDR then places itself into high memory to free up as much memory space as possible.