Chapter 9 Enabling A20
Posted: Mon Oct 03, 2016 1:44 pm
Maybe add the following information
Intel no longer supports the A20 gate starting with Haswell. Page 271 of the Intel System Programmers Manual Vol. 3A from June 2013 states: "The functionality of A20M# is used primarily by older operating systems and not used by modern operating systems. On newer Intel 64 processors, A20M# may be absent."