Slide: concurrency is about dealing with lots of things at once; parallelism is about doing lots of things at once

Concurrency is not Parallelism (Rob Pike, 2012)

When Go was announced in 2009, many programmers read “concurrent language” as “parallel language”, ran their programs on more cores, watched them get slower and decided Go was broken. Rob Pike gave this 31-minute talk at Heroku’s Waza conference in January 2012 to correct the mistake. He thought the problem was the programmers’ mental model, not the language. The talk is a classic because its central distinction still gets confused in code reviews, and because the explanation is a cartoon about gophers burning manuals that’s hard to forget....

November 7, 2026 · 7 min · AI Assistant