I want to understand computers more deeply, especially how the hardware, operating system, shell, and kernel fit together. Writing a small kernel seems like a good educational project rather than something intended for production use. I can write basic C programs, understand common computer components, and have a general idea of how CPUs work. I currently use Linux with KDE, but I am not an experienced systems or Linux developer. What topics, books, tools, and beginner projects should I work through first?
5 Answers
This is a perfectly reasonable learning project if you keep the scope small. The OSDev documentation, a bare-bones kernel tutorial, xv6, Pintos, and educational operating-system projects are all useful starting points. Begin by booting a tiny program, writing output, handling interrupts, and gradually adding memory management and basic scheduling. Test everything in a virtual machine so you cannot damage your main system.
An operating-systems design book is also worth reading alongside the code, since it explains the ideas behind processes, memory, filesystems, and hardware interaction.
Keep your first target extremely modest: boot successfully, switch into the desired CPU mode, print a message, handle one keyboard input, and perhaps implement a tiny command loop. A production-quality kernel needs virtual memory, drivers, multitasking, security, filesystems, networking, debugging facilities, and support for complicated firmware and hardware. That is far beyond a first project, but building a small teaching kernel is still valuable because the knowledge is the main reward.
Do not begin by trying to build a complete modern kernel. Start with a boot-sector or bare-metal program that initializes basic hardware, writes text to the screen, reads a key, and manages a small amount of memory. You will quickly encounter issues such as the lack of malloc, CPU modes, interrupts, and device access. A virtual machine or a simple development board is a safer environment for experimenting.
That sounds like a good way to understand the low-level pieces before attempting anything larger. I’m treating this as a hobby, so I can build it up slowly.
A useful structured path is to work through NAND2Tetris, then study algorithms and data structures, and finally read an operating-systems text such as Operating Systems: Design and Implementation. NAND2Tetris builds up from logic gates and hardware to a simple operating system, while the later material covers processes, scheduling, memory management, filesystems, and device drivers in more depth. You do not need a computer-science degree, but you do need patience and a willingness to study a lot of fundamentals.
Another approach is to modify and recompile an existing educational or open-source kernel before writing one from scratch. That lets you see the build process and experiment with small changes without having to solve booting, hardware setup, and every operating-system subsystem at once. You can also learn a great deal by writing small C and assembly programs for a simple board or emulator.
Thanks, I’ll start with the bare-bones material and look at the educational operating systems as I go.