How Computers Really Work Cover

How Computers Really Work

A Hands-On Guide to the Inner Workings of the Machine
by Matthew Justice
December 2020, 380 pp.
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Download Chapter 2: BINARY IN ACTION


How Computers Really Work is a hands-on guide to the computing ecosystem – from circuits, to memory and clock signals, machine code, programming languages, operating systems, and the internet. You won’t just read about these concepts, you’ll test your knowledge with exercises, and practice what you learn with 41 hands-on projects that bring the information to life. You’ll build digital circuits, craft a guessing game, convert decimal numbers to binary, examine virtual memory usage, run your own web server, and more.

Explore concepts like how to:

  • Think like a software engineer as you take a real world concept and describe it with data.
  • Use Ohm’s and Kirchhoff’s laws to analyze the properties of an electrical circuit.
  • Think like a computer as you practice binary addition and execute a program in your mind, step-by-step.

The book’s 41 projects will have you translate your learning into action, as you:

  • Build and measure a circuit: Learn the fundamentals of working with circuits and how to use a multimeter to measure resistance, current, and voltage.
  • Build a half adder to see how logical operations in hardware can be combined to perform useful functions.
  • Write a program in assembly language, then examine the resulting machine code.
  • Learn to use a debugger, disassemble code, and hack a program to change its behavior without changing the source code.
  • Use a port scanner to see which internet ports your computer has open.
  • Run your own server and get a solid crash course on how the web works.

And since a picture is worth a thousand bytes, chapters are filled with detailed diagrams and illustrations to help clarify technical complexities.

Requirements: The projects require a variety of hardware – electronics projects need a breadboard, power supply, and various circuit components; software projects are performed on a Raspberry Pi. See Appendix B or this page for a complete list. Even if you skip the projects, the book’s major concepts are clearly presented in the main text.

Author Bio 

Matthew Justice is a software engineer. He spent 17 years at Microsoft where he took on various roles, including debugging the Windows kernel, developing automated fixes, and leading a team of engineers responsible for building diagnostic tools and services. He has worked on low-level software (the operating system) and on software far removed from the underlying hardware (such as web applications). Justice has a degree in electrical engineering. When not writing code or building circuits, he enjoys spending time with his family, hiking, reading, arranging music, and playing old video games.

Table of contents 


Chapter 1: Computing Concepts
Chapter 2: Binary in Action
Chapter 3: Electrical Circuits
Chapter 4: Digital Circuits
Chapter 5: Math with Digital Circuits
Chapter 6: Memory and Clock Signals
Chapter 7: Computer Hardware
Chapter 8: Machine Code and Assembly Language
Chapter 9: High-Level Programming
Chapter 10: Operating Systems
Chapter 11: The Internet
Chapter 12: The World Wide Web
Chapter 13: Modern Computing
Appendix A: Answers to Exercises
Appendix B: Resources

View the detailed Table of Contents
View Appendix B: Resources