Chapter 1: Introduction

"At present I am, as you know, fairly busy, but I propose to devote my declining years to the composition of a textbook which shall focus the whole art of detection into one volume."

—SHERLOCK HOLMES, THE ADVENTURE OF THE ABBEY GRANGE

This book tells you how to find out what's wrong with stuff, quick.

How Can That Work?

How can something that's so short and easy to read be so useful? Well, in my twenty−six years of experience designing and debugging systems, I've discovered two things
- When it took us a long time to find a bug, it was because we had neglected some essential, fundamental rule; once we applied the rule, we quickly found the problem.
- People who excelled at quick debugging inherently understood and applied these rules.

Isn't It Obvious? 🙄

As you read these rules, you may say to yourself, "But this is all so obvious."
Don't be too hasty; these things are obvious (fundamentals usually are), but how they apply to a particular problem isn't always so obvious.
And don't confuse obvious with easy—these rules aren't always easy to follow, and thus they're often neglected in the heat of battle.

Anyone Can Use It

Throughout the book I use the term engineer to describe the reader, but the rules can be useful to a lot of you who may not consider yourselves engineers.

⇒ I disagree 😠 most of the stories need an engineer (mostly a hardware engineer) to understand them

It'll Debug Anything

This book is general; it's not about specific problems, specific tools, specific programming languages, or specific machines.
Rather, it's about universal techniques that will help you to figure out any problem on any machine in any language using whatever tools you have.

But It Won't Prevent, Certify, or Triage Anything

While this book is general about methods and systems, it's very focused on finding the causes of bugs and fixing them.

More Than Just Troubleshooting

Though the terms are often interchanged, there's a difference between debugging and troubleshooting, and there's a difference between this debugging book and the hundreds of troubleshooting guides available today.
- Debugging usually means figuring out why a design doesn't work as planned.
- Troubleshooting usually means figuring out what's broken in a particular copy of a product when the product's design is known to be good—there's a deleted file, a broken wire, or a bad part.