After writing this post the logical next step is writing something about launchd.
launchd is a tool created by Apple some years ago (launched in 2005 with OS X 10.4 Tiger). It is open source and licensed under the Apache License.
launchd has two main goals:
- Boot the system
- Maintain services
If you think that it resembles systemd no, you are not crazy: In Rethinking PID 1 Lennart Poettering (a Red Hat engineer author of systemd) mentions launchd as a source of inspiration.