Matthew Justice - How Computers Really Work: A Hands-On Guide to the Inner Workings of the Machine

A Hands-On Guide to the Inner Workings of the Machine

by Matthew Justice

San Francisco

HOW COMPUTERS REALLY WORK. Copyright 2021 by Matthew Justice.

All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher.

ISBN-13: 978-1-71850-066-2 (print)

ISBN-13: 978-1-71850-067-9 (ebook)

Publisher: William Pollock

Execuitve Editor: Barbara Yien

Production Editor: Katrina Taylor

Developmental Editor: Alex Freed

Project Editor: Dapinder Dosanjh

Cover Design: Gina Redman

Interior Design: Octopod Studios

Technical Reviewers: William Young, John Hewes, and Bryan Wilhem

Copyeditor: Happenstance Type-O-Rama

Compositor: Happenstance Type-O-Rama

Proofreader: Happenstance Type-O-Rama

The following images are reproduced with permission:

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phone: 1.415.863.9900;

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Library of Congress Cataloging-in-Publication Data:

Names: Justice, Matthew, author.
Title: How Computers Really Work : a hands-on guide to the inner workings of the machine / Matthew Justice.
Description: San Francisco : No Starch Press, Inc., [2020] | Includes
index.
Identifiers: LCCN 2020024168 (print) | LCCN 2020024169 (ebook) | ISBN
9781718500662 (paperback) | ISBN 1718500661 (paperback) | ISBN
9781718500679 (ebook)
Subjects: LCSH: Electronic digital computers--Popular works.
Classification: LCC QA76.5 .J87 2020 (print) | LCC QA76.5 (ebook) | DDC
004--dc23
LC record available at https://lccn.loc.gov/2020024168
LC ebook record available at https://lccn.loc.gov/2020024169

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The information in this book is distributed on an As Is basis, without warranty. While every precaution has been taken in the preparation of this work, neither the author nor No Starch Press, Inc. shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it.

To my family, who believed in me while I tried something new.

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). Matthew has a degree in electrical engineering. When hes not writing code or building circuits, Matthew enjoys spending time with his family, hiking, reading, arranging music, and playing old video games.

Dr. Bill Young is Associate Professor of Instruction in the Deptartment of Computer Science at the University of Texas at Austin. Prior to joining the UT faculty in 2001, he had 20 years of experience in the industry. He specializes in formal methods and computer security, but often teaches computer architecture, among other courses.

Bryan Wilhelm is a software engineer. He has degrees in mathematics and computer science and has been working at Microsoft for 20 years in roles ranging from debugging the Windows kernel to developing business applications. He enjoys reading, science-fiction movies, and classical music.

John Hewes began connecting electrical circuits at an early age, moving on to electronics projects as a teenager. He later earned a physics degree and continued to develop his interest in electronics, helping school students with their projects while working as a science technician. John has taught electronics and physics up to an advanced level in the United Kingdom and ran a school electronics club for children aged 11 to 18 years, setting up the website http://www.electronicsclub.info/ to support the club. He believes that everyone can enjoy building electronics projects, regardless of their age or ability.

1
COMPUTING CONCEPTS

2
BINARY IN ACTION

3
ELECTRICAL CIRCUITS

4
DIGITAL CIRCUITS

5
MATH WITH DIGITAL CIRCUITS

6
MEMORY AND CLOCK SIGNALS

7
COMPUTER HARDWARE

8
MACHINE CODE AND ASSEMBLY LANGUAGE

9
HIGH-LEVEL PROGRAMMING

10
OPERATING SYSTEMS

11
THE INTERNET

12
THE WORLD WIDE WEB

13
MODERN COMPUTING

A
ANSWERS TO EXERCISES

B
RESOURCES

An enormous thank you to my wife, Suzy, who acted as my informal editor, providing me with invaluable feedback. She scrutinized every word and every concept through multiple drafts of this book, helping me refine my ideas and express them clearly. She encouraged and supported me in this endeavor from concept to completion.

Thanks to my teenage daughters, Ava and Ivy, who read my early drafts and helped me see my writing through the eyes of younger learners. They helped me avoid confusing language and showed me where I needed to spend more time explaining things.

I want to express gratitude to my parents, Russell and Debby Justice, who always believed in me, and who provided me with ample opportunities to learn. My love of the written word comes from my Mom, and my engineering mindset comes from my Dad.

Thank you to the entire team at No Starch Press, especially Alex Freed and Katrina Taylor, and thanks to my copyeditor, Rebecca Rider. This was my first time authoring a book, and the editors at No Starch patiently guided me through the process. They saw opportunities for improvement that I hadnt considered, and they helped me communicate my ideas clearly. Ive gained a new appreciation for the value that a publishing team can bring.

Im thankful for this books technical reviewers, John Hewes, Bryan Wilhelm, and Bill Young, who diligently examined the details of my writing. Their input resulted in content thats more accurate and more complete. They each brought a unique perspective and shared their valuable expertise.

Thanks to all the people at Microsoft who mentored me and collaborated with me throughout the years. Ive been fortunate to work with some incredibly talented, intelligent, and knowledgeable folkstheres too many of you to list! Im only able to write a book like this because some great people at Microsoft took the time to share their knowledge with me.