Replacing SysV init is not easy, unless you want to copy the majority of its problems as well.

Actually, replacing van Smoorenburg init is easy, because very few softwares actually use /etc/inittab as a mechanism. "On the fingers of one hand" is actually close to the mark: inittab is used by van Smoorenburg rc, the old style startup for things like runit and daemontools, and a couple of private projects that people have not published but to whose users/creators I have had to explain the death of inittab.

Replacing van Smoorenburg rc is somewhat harder, but OpenRC does exist. As indeed does Mewburn rc (albeit that that is designed to run under FreeBSD init rather than van Smoorenburg init).

Three points to learn for these systemd discussions:

- init is not rc.

- We do not live in a world where nothing happened in between 1992 and 2011. A lot of things were done, a lot of softwares now exist, and the world did not step from van Smoorenburg init+rc to systemd. (Indeed, in 1992, the AIX SRC already existed.)

- van Smoorenburg init+rc are themselves clones of other softwares. These clones over the years added things like parallel startup with startpar, dependency ordering with insserv, faster boot times by switching to a shell with less startup overhead caused by its interactive-mode features, and a distinction between emergency and rescue modes.

* http://blog.darknedgy.net/technology/2015/09/05/0/

* http://jdebp.eu./FGA/inittab-is-history.html

* http://jdebp.eu./FGA/system-5-rc-problems.html

* http://uselessd.darknedgy.net/ProSystemdAntiSystemd/

* http://jdebp.eu./FGA/emergency-and-rescue-mode-bootstrap.htm...

I didn't say that it was easy, I said that it would be easy relative to the effort necessary to replace Systemd.