What’s a Good Learning Path for Building a Simple Operating System?

Treat the project as a sequence of small milestones rather than trying to build a complete OS immediately. Learn C, pointers, data structures, debugging, basic CPU architecture, and enough assembly to understand calling conventions and registers. Then experiment in an emulator such as QEMU so mistakes do not depend on your physical hardware. You can use a teaching project like xv6 or a hands-on course such as Nand2Tetris to connect architecture, compilers, and operating-system ideas. After that, an OS-development guide and a reference text will make the lower-level details much easier to follow.

It may be more motivating to begin with a smaller systems project, such as a text editor. A genuinely useful editor can produce visible results quickly, while even a minimal OS may take a long time before it can do much beyond booting and printing text. Building an editor teaches file formats, memory management, input handling, parsing, terminal control, and debugging without requiring you to implement a bootloader and hardware drivers first. You can write it in C, Rust, or another language with good control over memory and system calls, then move toward kernel work once those fundamentals feel comfortable.

A useful path is to learn basic computer architecture, become comfortable with C and a little assembly, and then study operating-system concepts while building small components. An OS is not written entirely in assembly: most of a simple kernel is commonly written in C or another compiled systems language, while assembly is used for startup code, context switching, interrupt entry, and other hardware-specific sections. A practical starting point is the OSDev Getting Started material, along with an operating-systems text such as Operating System Concepts by Silberschatz, Galvin, and Gagne or Modern Operating Systems by Tanenbaum and Bos. Start with a bootable “hello world,” then add text output, keyboard input, interrupts, memory management, processes, and scheduling one feature at a time.