What's good resource to understand a small Linux OS?

I've tried Linux From Scratch. They don't explain enough and I don't like patches or updates. I do like X-Windows, Mozilla, Octave, and OpenOffice. I'm a Linux beginner, but I want a barebones command line OS that I can eventually add applications to after compiling them from source. Before adding any applications I want to understand what each section of base OS code is supposed to do. I want to micromanage my computer from bootloader through Kernel to Shell, but I don't want to write all of my own code or necessarily even read the exisiting code line by line. What I do I want is to have a general idea of what each section is doing and peruse the code. I just want a bare computer without any fat. That's a CPU, RAM, floppy & HDD, mouse, keyboard, Video output, and Network driver - That's IT! Period! It used to be (DOS) that I had a shell and I put each program in its own place. I want to (once again) know which processes are running and who they belong to and keep them to a minimum. When I remove something, I want to know it has been removed everywhere. Are there any on-line resources that are tailored for me? I just barely understand some basic assembly and although my C is rusty, I have no fear to read the help/manual pages for each command. My ideal OS would turn on fast and I could back it up or reinstall it easily. I imagine that once it is in place and works well I would add X-Windows followed by OpenOffice and then Mozilla and finally Octave.