Operation Manual

8
The systemd daemon
The program systemd is the process with process ID 1. It is responsible for initializing
the system in the required way. systemd is started directly by the Kernel and resists
signal 9, which normally kills processes. All other programs are either started directly
by systemd or by one of its child processes.
NOTE: Using System V init rather than systemd
Being fully compatible, both systemd and System V init (SysV init) can act as
a drop-in replacement for each other. If you prefer to use the SysV init rather
than systemd, press F5 on the boot screen and choose System V. To make
this a permanent choice, install the package sysvinit-init which will replace
the systemd-init package.
Starting with openSUSE 12 systemd is a replacement for the popular SysV init dae-
mon. systemd is fully compatible with SysV init (by supporting init scripts). One of
the main advantages of systemd is the fact that it considerably speeds up boot time
by aggressively paralleling service starts. Furthermore, systemd only starts a service
when it is really needed. For example, the printing daemon cupsd is not started during
boot time, but rather when a user prints a document for the rst time after having
booted the system. systemd also supports Kernel Control Groups (cgroups), snapshot-
ting and restoring the system state and more. See http://www.freedesktop
.org/wiki/Software/systemd/ for details.
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