Check-then-act: the bug that pays users twice
In a take-home assessment, I wrote a withdraw endpoint. To stop duplicate requests, it first checked Redis for the idempotency key, and if the key wasn't there, it saved the key and processed the withdrawal. It looked correct. It passed every test I wrote. And it had a bug that can pay the same request twice. The bug has a name: check-then-act. Once you learn to see it, you find it everywhere: bonuses, coupons, refunds, follows, stock counts, daily limits.
Docker Mastery: The Definitive Guide for Software Engineers
In modern software engineering, the gap between development and production is a major hurdle. Docker has bridged this gap by introducing containerization, fundamentally changing how we build, ship, and run applications.
Why Docker Feels Like a Rocket on Linux but Drags a Little on Windows and Mac
If you've spent any time working with Docker, you've probably noticed something — on Linux, Docker just flies. Containers spin up instantly, everything feels snappy, and the whole experience is smooth. But on Windows or Mac? It's still usable, but there's a noticeable difference. A little sluggish, a bit slower to start up. Why does this happen? Today I want to break it down properly — not in a dry textbook way, but in a way that actually makes sense.
Bootloader Explained: The Bridge Between Hardware and Your OS
When you press the power button, your computer is completely clueless. Here's how a bootloader brings it to life — step by step.
With multiple OS, Who's the Real DON?
A simple explainer on how bootloaders work, what happens when you have 3 operating systems installed, and who actually controls your PC at startup.