"Booting. Sometimes it seems like it takes forever. What's the
computer doing all that time? How do you find out?
"The Linux boot sequence is surprisingly simple, and the best
part is that almost all of it is controlled by shell scripts you
can read -- and even edit yourself.
"Today's tutorial will take you through boot camp, focusing on
the classic "SysV init" methods Linux has always used. Part II will
discoss some of the changes on systems like Ubuntu as they
gradually migrate to a new "Upstart" model.
"First, Grub loads the kernel
"When you power your machine on, a program called grub takes
control. It reads the first sector of your disk, figures out where
to look for the operating system, and starts the kernel running.
Then it gets out of the way and the kernel takes over: usually
you'll see a brief message like "OK, loading the kernel"."