Information systems, step by step

Names, requests, packets and instructions traced through the IT systems that hold the modern world together.

How DNS Domain Name Resolution Works

A name turned into an address through a chain of lookups.

How the HTTP Request-Response Cycle Works

Browser asks, server answers, and the page appears.

How IP Packet Routing Across Networks Works

Packets hopping from router to router toward their destination.

How a CPU Pipeline Instruction Flow Works

A simplified pipeline where several instructions advance at once.

How an SSD NAND Flash Cell Works

How a storage cell traps charge to hold a bit, in cutaway.

How Ethernet CSMA/CD Collision Detection Works

Devices listening, sensing a clash and backing off to retry.

How the TCP Three-Way Handshake Works

A timing diagram of the three messages that open a connection.

TCP vs UDP Comparison

Reliable ordered delivery versus fast, fire-and-forget packets.