On infrastructure at scale - a cascading failure of distributed systems (2019) - all the things that started failing in Target’s infrastructure. It’s a nice story of how complex systems interact. It even has oscillating behaviour.

Laws of tech - commoditize your complement (2018) - an article on Gwern.net about Joel Spolsky’s pattern of “comoditizing your complement”. Or making sure a complementary product to yours has many providers, or is open source, or otherwise making it easy and cheap for your customers to use. The bulk of the article is a long list of such occurences.

Communication is a core skill for programmers (2019) - true words. So much of what an engineer does, especially as they become more senior, is persuasion and effective communication. Design docs, postmortems, documentation, product pitches etc. are some day-to-day cases where this is needed. So it’s best one is always practicing this skill.

How fast can you multiply really big numbers? (2019) - betcha you didn’t know you can multiply numbers via the fast Fourier transform? And that it’s faster for “big numbers” too - not just a theoretical exercise.

How fast can you multiply matrics? (2018) - a complement to the other one. Strassen showed that you can do it in under $O(n^3)$ which sparked off a search to find the theoretical lower bound for this. It sits at $O(n^2.37)$ right now, with a natural limit of $O(n^2)$ which some folks believe is actually doable.