You open a website in Madrid and the packets reach a server in Virginia passing through a dozen networks owned by different companies that compete with each other and share no boss. There is no centra...
Two people type into the same paragraph at the same time, each from a different city, and neither loses what they wrote. Behind that everyday scene lies a fairly serious computer science problem: how ...
For decades, talking to a disk from a program meant one request after another: the process called into the kernel, the kernel did the work, the process waited and called again. Every one of those syst...
There is an idea that sounds like a contradiction in any modern database engine: to write fast, you must avoid modifying what is already written. LSM engines (short for Log-Structured Merge) take that...
There is a layer of software that has changed, over the last few years, the way Linux servers are observed and protected, and it almost never makes the headline: eBPF. Its starting idea is easy to sta...
For decades, a web connection leaned on an inseparable pair: TCP to open a reliable channel and HTTP to request and deliver resources. That scheme worked well until the web stopped being a collection ...
Every time you log into a web application, a small object with three sections decides whether your next request is yours or an impostor’s. It is called a JSON Web Token (JWT), and its success co...
When you type a word in a search engine, millions of pages that contain it reappear within milliseconds. It is tempting to imagine that engine “reading” your documents on the fly and compa...
A bank cannot charge the same payroll twice. An airline must not sell the last seat to two passengers at the same time. Currency exchange bets, shopping carts, like counters: behind all of these there...
When you fire thousands of requests at an API in a single second, most people expect the server to answer every single one. A server that always answers, with no brakes, is designed to collapse. Befor...
Imagine you and another person edit the same document offline, on different devices. When you both get back online, the two copies must become one again. No referee, no locking, no lost edits. That ap...