On a 286 or better PC equipped with more than 640 kB of RAM, the additional memory would generally be re-mapped above the 1 MB boundary, since the IBM PC architecture reserves addresses between 640 kB and 1 MB for system ROM and peripherals.
He said to me: “It is done. I am the Alpha and the Omega, the Beginning and the End. To the thirsty I will give water without cost from the spring of the water of life. Revelation 21:6 NIV