The powerd daemon is started by pmconfig(1M)
to monitor system activity and perform an automatic shutdown using the
suspend-resume feature. When the system is suspended, complete current state
is saved on the disk before power is removed. On reboot, the system automatically
starts a resume operation and the system is restored to the same state
it was in immediately prior to suspend.
Immediately prior to system shutdown, the daemon notifies syslogd(1M) of the shutdown, which
broadcasts a notification.