Code: The Hidden Language of Computer Hardware and Software

This is a wonderful book. It claims it wants the reader to understand computers the way computer engineers do. And, if you read carefully, follow the diagrams and think through the explanations,
you will start to. He shows how the main components can be built out of the clever use of a few ordinary bits of technology, all over a hundred years old. I started programming computers about 40 years ago and have a Ph.D in computer science, so I mostly already knew everything in here. But I had the most fun I have had in years reading the first half or so. One of my first programming classes in college involved learning exactly this material. Using little bits of code to simulate relays, switches and such, we built logic gates, then used that code to build 1/2 adders, adders and other components. It was the same sequence of ideas and techniques presented here. We wrote the code in assembler, I think for the PDP-11, or maybe it was in the Mix language used in the Knuth books. This class was my favorite of all my programming classes and reading this book took me back there.
Now I am inspired to do it again, using the circuits described in this book to build a simulation for the web.

So now you think this book is for highly trained engineers and it absolutely isn't. The background you need is you have to understand that switches go on and off, and if you hook a light bulb to a battery, it will light up. The author carefully and fully explains the rest. After getting through this you will know why computers use binary arithmetic, how Braille and Morse code are related, what mathematical logic is. Every day you use that amazing phone or desktop computer to make and play video and music, talk to people anywhere in the world, find out anything you want to know. Read this book and you will know it's not magic, it's the very clever use of a few very simple tools.

This book would be great for a high school student who is interested in science, math or technology and for anybody who wants to know how computers really work, not just what app does what. This was easily my favorite book I read this year.

An excellent, approachable work suited for anyone interested in computers, demanding no need for technical background. As an individual with large amounts of experience in several of the topics presented within, I still found this work enjoyable and it filled in some gaps in the entire stack of the computer. While the later chapters show the age of the text, the combined historical summary of events and technical deep dive into operation was highly enjoyable.

This book is quite incredible. You start with braille and simple light switches, make your way to oscillators, flip-flops and multiplexer, and suddenly you understand how computer hardware works. And that's coming from someone who already thought they “sorta” understood how it worked. I didn't really. Now I do. Best bottom-up education ever.

I first came across this book around 2005, while studying C# at the university. Back then I was reading a recommended book on C# programming by Charles Petzold, which I liked, and I looked into other books written by him. “Code” immediately caught my attention but for various reasons I didn't buy the book for 10 more years and I didn't read it until this month.

Well, the long wait was certainly worth it as this was one of the best introductions to computing I've ever read! The author guides us through the process of building a simple computer from scratch in an extremely detailed, yet entertaining way, and we learn a lot about a lot of topics as we go along. That's probably one of the best texts on the history of computing as well, and modern electronics/communication tech in general.

So, why 4 stars instead of 5 then? Well, the book quality varied with chapters and I definitely didn't enjoy the final chapters as much as the earlier ones. Perhaps because those were the most outdated (e.g. the one on peripherals), or simply because that's the part of computing I didn't really need a refresher on (operating systems, programming languages, etc). Still, I have to admit the book has aged very well (it was written way back in 1999!) and most of its content is pretty timeless.

Funny enough, Charles Petzold has recently announced a second edition of “Code” that's due any day now - mid-August 2022. Let's see if I'll manage to read it in less than 17 years this time around!