Visualizers
Learn by moving things
Interactive explainers for the ideas behind retrieval, embeddings, and agents. A formula tells you what is true; dragging a vector shows you why. Each one also appears inside the article it belongs to, and runs entirely in your browser, so drag, poke, and break it.
Deep dive: the hard part, made real
From: How to Design a System →Step six. Short codes are like locker numbers: two links must never share one. Watch a code get minted, collide, and retry until it is unique.
The hard parts are where a design becomes real: short codes that never collide (check, and retry on a clash), and a plan for when the cache goes down (fall back to the store).
A request's journey to a server
From: How a Request Finds a Server →What happens when you type a web address: a dot hops through the five stops, you, DNS, load balancer, gateway, server, before a page comes back.
Every request hops through each of these before a page comes back.
DNS: a name becomes a number
From: DNS: The Internet's Phone Book →DNS as a contacts app. Look up guptasachinn.com, get 192.0.2.5. The first visit asks a resolver; the next is instant from the cache (TTL).
The first time, your browser asks a DNS resolver to turn the name into an address.