http://zhidao.baidu.com/link?url=y-EQc_KiZHTsQFzD8e1AeWPQstkZU1EvQNZrYkFIBiibtizB_z48edyAChgLXQWrKy17EIDtaJ961NpxMMoq_q
http://www.111cn.net/sys/linux/41952.htm
http://zhengdl126.iteye.com/blog/1749014