cfenollosa/os-tutorial

This is a step-by-step tutorial for learning how to build a minimal operating system from scratch. Rather than reading an existing kernel, the tutorial walks through writing a working OS piece by piece: starting from the very first boot sector, the tiny blob of code a computer runs before any operating system loads, then moving into 32-bit mode, jumping from Assembly language into C, adding interrupt handling (the mechanism that lets hardware events like key presses notify the CPU), implementing basic screen output and keyboard input, and eventually working toward a simple shell and memory management. Each lesson is kept intentionally short, the README estimates 5 to 15 minutes per lesson, with a brief written explanation followed by heavily commented code samples. The philosophy is minimal theory and maximum hands-on code, aimed at programmers who are comfortable with low-level computing concepts but have never gone all the way down to building a bootloader and kernel themselves. A programmer curious about how computers actually start and how an operating system is built at the lowest level would work through this when they want practical experience rather than textbook reading. The README warns it is an old, abandoned project with known technical issues, and suggests also consulting more modern and authoritative sources on OS development. It is written in C and Assembly.