Linux boot sequence
 

I was studying an article on "linux startup sequence" here i face a quote:

I can't understand what they are saying because I don't know some terms used here:

1. What is root file system used by linux ?
2. what is initial ramdisk? Why this is necessary? Can linux bypass using initial ramdisk ?


beside this, I have some other questions regarding:

3. What is LILO and what about lilo installer? whats the difference between them?
4. what is Bios call?
5. what the "map" used by LILO and what does this map contains?

Plz comment.

Open a shell and type "cd /" at the prompt. Then type "ls" - you're now looking at the root filesystem.

Lilo is a LInux LOader. It tells your computer what OS to boot, with what options - eg I can choose to boot either Gentoo or Slackware, to either a GUI or a text-based environment.

What options Lilo has on bootup depends on the lilo.conf file you've installed in it.

$ cat /etc/fstab
it's the one with a mount point of `/'. See man fstab

2. what is initial ramdisk? Why this is necessary? Can linux bypass using initial ramdisk ?
basically it's using your RAM as a file system for speedup. I don't think it's necessary per se, but it's a Good Thing (tm).
$ find / -name '*initrd*' # or
$ locate initrd

beside this, I have some other questions regarding:

3. What is LILO and what about lilo installer? whats the difference between them?
gnu/LInux LOader; a boot loader that's simpler and less powerful than grub, and thus less error-prone :D (don't get me wrong, I haven't been bitten by grub or anything--but the KISS principle *always* applies)