> My question would be that after the grub is loaded and I am about > ready to boot the system what is happening. Loads the kernel, runs > initrd or what? What are those init things? What are runlevels? What > is very necessary and required to boot a system?
Assuming your computer is IBM-PC style the boot chain for Linux is as follows: (Control is passed on to it's succesor 1) BIOS reads BootLoader (GRUB) from MBR. 2) BootLoader loads Kernel with some parameters. Once the kernel gained control over the system OS is running in it's most primitive form. The optional initrd step is for those who have things to get done before hardware is accessible. (e.g. loading modules before mounting root filesystem residing on disk) The next step is to provide some services. (tty, login, shell, filesystem, ...) By default linux runs /sbin/init. This can be overridden by passing the 'init' kernel parameter. (e.g. init=/bin/bash) Init reads it's configuration from the /etc/inittab file. This is where the runlevels and a default runlevel are defined. Generally for each runlevel a cascade of bootscripts is launched. -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
