Code: The Hidden Language of Computer Hardware and Software

Another book that, after finishing, left me with the thought: I wish I had read this sooner.

In 2024, I was a web programming professor, and the book’s approach made me reflect on how I introduced the subject. I remember using Morse code in the first class to explain communication, but I never made the connection to binary numbers the way Petzold does.

The book brilliantly starts with simple communication examples, like using flashlights, and builds a logical sequence that moves through Morse code, Braille, and arrives at binary logic. It makes us question the basics: why do we count from 1 to 10? The answer: our ten fingers. This reflection opens the door to understanding how a computer, with its “two fingers” (on and off), uses a binary system.

The author guides us through the evolution of technology, from the telegraph, through relays, vacuum tubes, and transistors, to modern computers. He shows how each invention was a stepping stone to the next, culminating in the complex systems we have today.

For me, one of the most interesting parts was seeing the author create programs using logic circuits (something I hadn’t done since college) and then show how the same program would be written in Assembly. As someone who now works mainly with high-level languages, it was a nostalgic moment that reconnected me with the fundamentals of computing.

The reading made me reflect on how computing is a vast network of patterns and collaboration. Multiple ideas and companies communicate with each other: the chip manufacturer (Intel/AMD), the operating system developer (Microsoft/Apple), the kernel creator, and the software developers. This level of collaboration is so extensive that it’s now possible to write cross-platform software, like apps for iOS and Android (with React Native/Flutter) or for desktop (with Electron/Tauri), from a single codebase.

Ultimately, the book is about communication. We, as human beings, need to communicate, and technology is a tool that helps us do so in increasingly sophisticated and effective ways. It demystifies how computers “talk” and “think” through 0s and 1s, showing that behind all the complexity of modern technology, there are simple principles. It’s a read that inspires a deeper appreciation for what happens under the hood.