"For years, most Linux distributions have been using an init
daemon based on the one found in Unix System V. The init daemon is
spawned by the kernel itself, and tasked with booting the rest of
the system, starting all other processes, and taking care of them
when they need to be stopped or when they die. While the System V
init setup has worked well for Linux in the past, it hasn't aged
well--which is why we're replacing the aging init system with
Upstart in Ubuntu 6.10, codenamed Edgy Eft.
"Upstart is designed to be a replacement for System V Init
(sysvinit), with a different purpose than other init replacements
that have been developed. The problem that has been facing us as
we've attempted to make things 'just work' in Ubuntu is that modern
desktop computers and servers are very different beasts from those
in use ten years ago..."