Code
Code by Charles Petzoldby Charles Petzold
Ranked 5 of 7 computer science books by recommenders
Recommended for explaining how a digital computer works, from relays up to computation, in readable prose. Critics note that most images are missing from the latest printings.
Recommended for explaining how a digital computer works, from relays up to computation, in readable prose. Critics note that most images are missing from the latest printings.
8 people gave an opinion
- recommend it
- 7
- criticize it
- 1
- approval share
- 88%
Recommended in 5 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: not recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: not recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: not recommended
- September 2026: recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 7 people recommend itNeeds 10 or more, not met.
- 7 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 5 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Explains how computers work
“He explains how a digital computer works. Not sophisticated ones, not how it works on silicon, but how you turn relays into computation.”
Comment from 5 Sep 2026 in “Can guitar frets perform multiplication?” “For those interested in learning about the inner workings of computers, I also recommend the book Code by Charles Petzold.”
Comment from 15 Feb 2026 in “How Is Data Stored?” Called the must-read on this topic
“This is the book to read if you are interested in the topic”
Comment from 4 Jul 2026 in “Software, from First Principles” “Mr Petzold's book, Code, is marvel and you should read it”
Comment from 15 Mar 2026 in “The Appalling Stupidity of Spotify's AI DJ”
Other computer science books people recommend
The four most recommended other computer science books, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| The Garbage Collection Handbookby Jones, Richard | 16 | 5 | 76% | 4 | — | Approved |
| Beej's Guide to Learning Computer Scienceby Brian Hall | 15 | 2 | 88% | 1 | — | — |
| Code: The Hidden Language of Computer Hardware and Softwareby Charles Petzold | 12 | 0 | 100% | 8 | — | Approved |
| The Unix-Haters Handbookby Simson Garfinkel | 8 | 1 | 89% | 4 | — | — |
| Codeby Charles PetzoldThis page | 7 | 1 | 88% | 5 | — | — |
What people said
7 of the 8 comments that mention it, newest first. Each links to the original comment.
“He explains how a digital computer works. Not sophisticated ones, not how it works on silicon, but how you turn relays into computation.”
“This is the book to read if you are interested in the topic”
“Code by Charles Petzold (moves slower, recently updated)”
“advocates that it be done in a thoughtful manner”
“most of the images are completely missing from the latest printings”
“Mr Petzold's book, Code, is marvel and you should read it”
“For those interested in learning about the inner workings of computers, I also recommend the book Code by Charles Petzold.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.