"During the evolution of the original Unix, there was a split into two major branches of development. One is refered to as System V, and one as BSD. They have somewhat different approaches to running startup scripts at boot. Many Linux distributions, including Debian, which is the one I am most familiar with, use the System V approach.
"Before running startup scripts, the bootstrap process of getting a kernel loaded and a file system mounted have to take place. I'm not going to go into that..."