Notes by Ayyoub AmjahedEngineering notes on Java backends, identity and access management, and self-hosted infrastructure. Projects documented with their decisions and their mistakes.https://ayyoub.dev/enThe state lives outside the model: how a desk pet knows you haven't talked to it in three dayshttps://ayyoub.dev/blog/el-estado-vive-fuera-del-modelo/https://ayyoub.dev/blog/el-estado-vive-fuera-del-modelo/An LLM with memory gives you a friendly chatbot. A state machine with an injected clock gives you a creature. The line "I know" is only funny if it's true.Mon, 07 Sep 2026 00:00:00 GMTI spent days tuning the prompt, and what actually moved accuracy was changing the modelhttps://ayyoub.dev/blog/el-modelo-pesa-mas-que-el-prompt/https://ayyoub.dev/blog/el-modelo-pesa-mas-que-el-prompt/I went from 30.7 % to 100 % of days correct reading shift rosters. Almost none of that gain came from the prompt, and the metric that mattered wasn't accuracy.Wed, 02 Sep 2026 00:00:00 GMTThree layers, two problems: a GPU passthrough that stopped halfwayhttps://ayyoub.dev/blog/tres-capas-dos-problemas/https://ayyoub.dev/blog/tres-capas-dos-problemas/The device was in the container, the check confirmed it, and the app still couldn't see it. Because the app was running one layer further in. And once it could see it, it had no permission to open it.Tue, 01 Sep 2026 00:00:00 GMTThree times it "looked configured": verify by reading the result, not by assuminghttps://ayyoub.dev/blog/parecia-configurado/https://ayyoub.dev/blog/parecia-configurado/A sysctl that didn't persist, a udev rule that would never have fired and a sed that edited a comment. No command returned an error. The habit that catches all three is the same one.Mon, 31 Aug 2026 00:00:00 GMTA backup you never restore is a big folder with a reassuring namehttps://ayyoub.dev/blog/un-backup-que-no-se-restaura/https://ayyoub.dev/blog/un-backup-que-no-se-restaura/I set up automatic backups for nine machines and everything showed green. The photo library, the only irreplaceable data, was left out. What gave it away was a backup that finished too fast.Sun, 30 Aug 2026 00:00:00 GMT