Chapter 11. The Start-Up Files: init sysv

In the Beginning Was init
Runlevels

In the UNIX tradition, there are two system-startup schemes: the BSD scheme and the “System V” scheme, each one being named after the UNIX system which first implemented them. (Berkeley Software Distribution and AT&T UNIX System V). The BSD scheme is simpler, but the System V one, while not as easy to understand (which will hopefully change once you finish this chapter), is definitely more flexible to use in today's systems.