Code

As many other reviews said, the first part of the book is a brilliant, entertaining, easily understandable & accessible overview of underlying topics that relate to how "codes", electronic signals, alternate number systems & computers came about.The latter sections are considerably more dense, and required going back a few times, tracing the circuit diagrams with my finger, and Googling the finer points of electrical circuitry, how to do math in binary, octal, and hexadecimal, and other assorted topics covered in this wide-ranging work.I had classes a LONG time ago in electrical engineering, as well as a good amount of experience with binary, hex(adecimal), and programming, so given that background I could follow along fairly easily & connect the concepts to my existing knowledge. If you don't have any background at all in EE, Comp Sci, or programming, be prepared to re-read & re-re-read the chapters on logic gates, circuits, and how these bits of hardware physically compute & store basic arithmetic values in order to perform complex tasks. Those sections were the most challenging, but ultimately for me provided the most valuable information because it helped fill in the missing pieces of the puzzle in my prior knowledge.For anyone who wants to "learn to code," but you find yourself confused by or not really bothering to understand concepts like pointers, memory addresses, Boolean logic, or esoteric & ancient magic spells like "XOR" or Assembly Language, this book does an excellent job of explaining in real, physical hardware terms exactly what those mean and how they work.My only critique is that after ALL that fine-grained detail & historical backstory for most of the book, the final chapter crams roughly the last 40 years of computing into a few short pages, covering everything from Graphical User Interfaces & image compression to the internet & (rather outdated) descriptions of web browsers. It felt rushed & tacked on.I'd really like to see an update, or a companion book, that covers newer topics in such detail as the first half of this book.Overall though, this was a fantastic, educational if at-times-dense read. I had to work at it a bit, but that was the point.If you hate to read, don't want to learn, and are too lazy to work at it - buy it anyway to give him another $15 and then write a review explaining why it's the book/author's fault :P

I am a computer programmer by trade and sincerely wish I had this book 7 years back when I started formal education. During my 4+ years in the higher education system, and even after, I and my classmates (later colleagues) were taught how to program computers (in various languages) and many of the higher level ideas in programming (Data Structures, Algorithms, Program Structure, Etcetera, Etcetera, Etcetera) but we never really learned how the computers worked inside. Even to many trained programmers, or at least me:), these beige boxes can be something of a magical black box which we don't really understand at a fundamental beyond the point of it processing the instructions we give it in our chosen programming language. In school I recieved perhaps one single semester course that attempted to teach how these things worked inside, yet that course still skimmed on the inner workings, the teacher instead spent his time on how monitors drew pixels on the screen and how laser printers worked.....Looking back on it, I would blame the ignorance of the inner workings of computers that some programmers have on the decline of having to learn Assembly language (starting in the early nineties?), the lowest level programming language sans actual Machine Code, where one would be forced to deal with the raw inner workings of a computer naturally. I myself hope to learn it one day after reading this book :D Instead, I was taught the C programming language and what we learned in school became only more abstract in regards to the actual hardware...This is where this wonderful book came into play. Since I recieved it half-a-year ago, it must have been read/devoured by me a dozen times or more - it goes from teaching the make-up of various codes (morse, braille, etcetera) to showing how some simple to understand concepts can be combined until a working computer, calculator, etcetera, can be built....... it gives one a great foundation for learning what Computer Science is all about or gives a newer-generation Programmer, like me, much needed knowledge on how that beige box basically works, on a hardware level!The best thing is that those computer analogies can be finally thrown out the window - we all heard them before - like how "ram is like a table, or workspace. The bigger it is, the more things you can have ready and available at one time. The hard drive is like your drawers and cabinets. You can store more stuff there, but to use it, you have to take it out first and put it either on the table (RAM) or hold it in your hand (cache)." Petzold also uses analogies when he introdues topics but quickly moves beyond them, giving his audiences real understanding of the subject - which is very welcoming since analogies tend to explain function well but break down quickly when one is determined to learn more about a topic.It is probably one of the few computer books on my shelf that can't get outdated and that's good, because it still will be there in 20 years.