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= Overview =
=== Definition of systemd ===
According to Lennart Poettering, the developper of systemd:
'''systemd''' is a more efficient method of controlling processes. It has the flexibility to start services in parallel, and have them communicate with each other, even if they are restarted (respawned). This is particularly useful for system administrators to temporarily service or update services without affecting the other dependent services.
=== The Old Way: init ===
Upon computer boot-up, and after the Kernel process is started, it traditionally launched the '''init'''process (usually PID 1). This important process manages (launches) other common services. The init process also has the ability to manage process (for example, respawing or "restarting" processes if they are terminated for some reason).
Traditionally, the '''init program would run default processes''' that were defined in "shell scripts" contained in appropriate '''run-level''' directory. The run level is a defined state that the Unix/Linux system is currently in (for example, graphical-mode, text-based mode with networking, text-based mode without networking, etc).
=== Why Switch to systemd? ===
Why switch to systemd when the concept of init and run levels seemed to work for 40 years! If it isn't broke, why try to fix it?
=== The New Way: systemd ===
= systemd Command Usage =
=== General Concept ===
=== systdctrl ===
= Additional Resources =
:* YouTube Video (beyond init: systemd): [http://www.youtube.com/watch?v=TyMLi8QF6sw (beyond init: systemd)]
