To run the program please give -- ./apex_sim display 20 -- //you have to give soome kind of number other wise it wont work reference Dr Kannad Ghose notes www.stackoverflow.com www.reddit.com https://classroom.udacity.com/courses/ud007 - udacity course on HPCA https://github.com/adi2896/CS520-Project-1 https://github.com/shankyDoodle/apex-simulation-inorder-pipeline http://www.pythondiary.com/blog/http://www.pythondiary.com/blog/Oct.15,2014/building-cpu-simulator-python.html