Before starting Hadoop in either pseudo-distributed or fully distributed mode for the first
time, we need to format the HDFS filesystem that it will use.
This is not a very exciting output because the step is only an enabler for our future use
of HDFS. However, it does help us think of HDFS as a filesystem; just like any new storage
device on any operating system, we need to format the device before we can use it. The
same is true for HDFS; initially there is a default location for the filesystem data but no
actual data for the equivalents of filesystem indexes.
