Systemd - http://www.ibm.com/developerworks/cn/linux/1407\_liuming\_init3/index.html UpStart - http://www.ibm.com/developerworks/cn/linux/1407\_liuming\_init2/index.html sysvinit - http://www.ibm.com/developerworks/cn/linux/1407\_liuming\_init1/index.html