If you are taking an undergraduate operating systems course, you should already have some idea of what a computer program does when it runs. If not, this book (and the corresponding course) is going to be difficult — so you should probably stop reading this book, or run to the nearest bookstore and quickly consume the necessary background material beforecontinuing(bothPatt/Patel[PP03]andparticularlyBryant/O’Hallaron [BOH10] are pretty great books).