http://wiki.chinaunix.net/index.php/%E4%BD%BF%E7%94%A8GDB%E8%B0%83%E8%AF%95 http://blog.youkuaiyun.com/haoel/archive/2003/07/02/2879.aspx http://blog.youkuaiyun.com/lilingcx/archive/2007/07/26/1708680.aspx