Download Apache Hadoop : http://sourceforge.net/projects/hadoop.mirror/files/Hadoop%201.0.4/

These steps ensure that Hadoop is installed and available from the command line.

By setting the path and configuration variables, we can use the Hadoop command-line
tool. The modification to the Hadoop configuration file is the only required change to
the setup needed to integrate with your host settings.

Don't worry about some of the details here; we'll cover Hadoop setup and use later.