See also:
  Operating Systems\DOS\Expanded memory

The expanded memory manager goes by several names in DOS, depending
on the hardware and system. On most 386 or higher systems today,
that job is fullfilled by EMM386.EXE which uses the 386's protected
mode and possibly virtual 8086 mode to provide LIM-compliant paging.

The existence of actual hardware to provide memory and page it as
such is a typical feature of 286 and lower machines and the paging
is typically done by the hardware controller and a dedicated driver
that may have an entirely different name.