[JetSetWilly]

Arch made systemd the default in October 2012, and added it to repos in January 2012. There's only one "major" OS that was earlier, which is Fedora - to be expected given that systemd is a red hat project.

Suse was October 2014. Debian and Ubuntu were April 2015. RHEL was June 2014.

[the_why_of_y]

openSUSE 12.1 had systemd by default, released in Nov. 2011.

https://en.opensuse.org/Archive:Portal:12.1

[yAnonymous]

Ubuntu had Upstart in 9.04 (2009), as did others before they used systemd. I posted a source...