This is a question I recently asked in a comment at Slashdot. I didn't really get much of a response, so I decided I'd bring it to a place where I should have gone originally with it.
I'd like to put together a very fast booting Linux system, composed of just the bare minimum needed to be able to run something like BusyBox. I'm not one of those people who make a big deal out of boot times, I'm mainly interested from an academic point of view and am using this to try to learn a little more about how Linux works.
I've googled this topic and have found things like Linux From Scratch, but as far as I can tell these seem to have their own software on which you base whatever you're building. I was under the impression that all you need to boot is a file system, the Linux kernel, an initrd and then userland software for whatever you want to run. I've read that initrd isn't even needed if you compile SATA drivers into the kernel and maybe some other things. In fact I would say that another aim is to boot without using initrd at all, I only intend to use this on my computer for a bit of fun.
Are there any websites that contain a minimal list of things required to get Linux to boot?