systemd 225-1ubuntu4 (amd64 binary) in ubuntu wily

 systemd is a system and service manager for Linux. It provides aggressive
 parallelization capabilities, uses socket and D-Bus activation for starting
 services, offers on-demand starting of daemons, keeps track of processes
 using Linux control groups, supports snapshotting and restoring of the system
 state, maintains mount and automount points and implements an elaborate
 transactional dependency-based service control logic.
 .
 systemd is compatible with SysV and LSB init scripts and can work as a
 drop-in replacement for sysvinit.
 .
 Installing the systemd package will not switch your init system unless you
 boot with init=/bin/systemd or install systemd-sysv in addition.