You ask the disk to write a few bytes in a specific place, and you believe that is exactly what it does. In an SSD (solid-state drive, storage without moving parts that uses flash memory) that belief ...
Your program creates objects endlessly: a list here, a string there, a temporary user. Each one occupies a corner of memory. And when you stop using it, it would stay there forever, piling up until th...
Some operations in memory are astonishingly elegant. One of them is answering, almost for free, a question that at first glance seems expensive: “Is this item in this set?”. For that task ...
Before your browser loads this page —or any site with a padlock— a silent conversation takes place in a few milliseconds. It is the TLS handshake (TLS, Transport Layer Security: the protocol that encr...
Almost everything that holds your data today lives on more than one machine at once. And the moment several machines appear, an uncomfortable problem shows up too: they disagree. One server says the c...
Every running program believes it owns all of the machine’s memory for itself. That is not a marketing trick: this “illusion” is virtual memory, and without it modern operating syste...
You run SELECT * FROM pedidos WHERE cliente_id = 2421 and, depending on the table, the answer takes an instant or several seconds. The only meaningful difference between the two cases is usually a str...
You have an 800-page novel in front of you. You compress it with gzip and it takes up a quarter of the space. Not a single letter has disappeared: decompressing returns the exact text. What actually h...
Every time you open a large app, you are not connecting to a single machine but to hundreds of servers sharing the load. For your session and your data to always appear where they belong, those machin...
Picture a spreadsheet open to a hundred people at once: everyone reads, one writes, and nobody loses their work. At the scale of millions of transactions per second in a real database, that is called ...
When you type a ñ on your phone, the keyboard does not store the letter: it stores a number. And that number does not necessarily fit in a single byte (a unit of 8 bits, the smallest block a computer ...
We have all experienced it: a download that raced along suddenly slows to a trickle. The more people connect, the worse everything seems to run. That behaviour is not a fault in your provider: it is t...