Hardware Simulator
February 26th, 2009
If you download the software package from this page:-
https://www.nand2tetris.org/software.php
you will find a folder in projects called “demo” which contains three Xor files. If you open the Hardware Simulator and direct it to the “demo” folder the Xor.hdl file will run without errors because it is using builtin chips as expected, because it cannot find any other implementations of And, Or and Not.