programming my own kernel

Question

I need some directions to start learning about programming my own operating system kernel.

Just for educational purpouses.

How can I write my own Kernel?

Answer 1

I would first ask: why did you pick "writing a kernel?" Any answer other than "the idea of implementing my own task structures in memory to be swapped by a scheduler that I write and using memory that is managed by code that I wrote and is protected by abstractions of machine-level atomic instructions and is given I/O access through abstractions that sit atop actual hardware interfaces appeals to me" is probably a bad answer that indicates you haven't done any research whatsoever and are wasting your time.

If you answered similarly to the above, then you have a good starting point and you know what you need to research (that is, you are able to pinpoint to some degree what information you do not know but need to find out).

Either way, I don't think this question is worth asking. In one case, you have done no research of your own to discover if you can actually do this, and in the other case you asked an overly-broad question.

Answer 2

It isn't that hard, but you need to learn about proper resource management and low-level device I/O. If you're targeting a commodity x86 box, then you'll need to learn about how the BIOS works and how the disk is structured. For example, the BIOS will read the first block of the disk into memory at some fixed address and then jump to that address. Since there probably won't be enough space in one block to store your kernel, you'll need to write a boot loader to read your kernel off the disk and load it.

Writing a minimal kernel that does some simple multitasking and performs I/O using just the BIOS isn't too difficult, just don't expect to be throwing up any windows and mousing around any time soon. You'll be busy trying to implement a simple file system and getting read() and write() to work.

Answer 3

Maybe you can start by looking into OS/161, which is a Harvard's simplified operating system for educational purposes. The OS runs on a simulator, so you don't need a new machine to run it. I used it for my operating system course, and it really did help a lot.

Also I think you may really want to consider taking an operating system course if you haven't done so.