Quote: "Theres only 3 major Os's as you probably know, windows mac and unix/GNU/Linux"
Ooookay then, I'm going to leave that one slip, do a bit more research
@Osiris, just a little bit of whats involved:
You will most likely need to learn assembly, because an operation system is so low-level that most of the C libraries are OS-dependant.
You'd have to write a memory manager to handle RAM for application, a processor manager to handle CPU time for applications, filesystem implementations, if you want networking support you'll need to write a TCP/IP stack.
You'll need intricate knowledge of the workings of computers, memory offsets, bios, interrupts, you'll also need to do research on bootstrapping to get your OS to even start up.
If you're still interested,I've got a few links lying around somewhere on the subject which give quite a lot of info