I am a software developer (C/C++) and was looking a book about hardware internals i.e. how my computer works (CPU, branch prediction, cache lines, memory etc etc).Initially I bough Patterson&Hennessy but it was almost useless for me - it was hard to read, messy organization, no explanation for basics things.Then I bought this book, and WOW it was a great pleasure for me to read it. It was easy to read - I finished the book in ~4 weeks (reading it at evenings before going to sleep). Tanenbaum uses 'simplified English' - it is a great help for me as English is not my native language. The book starts from basic things known to most software engineers and goes deeper and deeper into details. Actually I went ahead and bought another his great book - 'Networks'.Some people are complaining about poor exercises - I cannot really evaluate it. I do not care about exercises, I mostly skipped it as I was interested in the theoretical part.