http://apache.01link.hk//hadoop/core/hadoop-0.21.0/
install guide
http://www.cnblogs.com/wayne1017/archive/2007/03/20/678724.html
hadoop quick start
http://hadoop.apache.org/common/docs/r0.20.2/quickstart.html#Supported+Platforms
sudo ssh localhost -p 443
sudo gedit /etc/ssh/sshd_config
ls -al file