I'm a big fan of http://www1.idc.ac.il/tecs/ http://www1.idc.ac.il/tecs/ (The Elements of Computing Systems) It takes you from logic gates all the way up, show

I'm a big fan of http://www1.idc.ac.il/tecs/ http://www1.idc.ac.il/tecs/ (The Elements of Computing Systems) It takes you from logic gates all the way up, showing just enough at each level to give you a real view into what's going on there. I think once you've got through this book, you'll have a great base for anywhere you want to go, including OS programming.