What is hdfs://, data.dir

[Ashish Jain <as...@gmail.com>]

Hello,

This is my second post in the forum and I would like to say that I am
amused with the kind of support from other folks. Thanks a lot. Here are
few more questions on how stuff works in hadoop:

Q1. What is hdfs://. Actually I ran a -copyFromLocal command and gave
source directory as /opt/temp/2.txt and target directory as hdfs://. Later
I used the namenode browser to browse through the file system and I can see
files listed in "/" location but physically I am unable to see the files in
OS. So here is the question what is hdfs://??

Q2. I set the dfs name dir and dfs data dir as following. I know name.dir
will store the meta information of what is stored in data nodes. However I
do not see anything stored in data.dir? Can some one explain what is this
data.dir for?
<property>
<name>dfs.name.dir</name>
<value>file:///opt/ApacheHadoop/nameDir/</value>
</property>

<property>
<name>dfs.data.dir</name>
<value>file:///opt/ApacheHadoop/dataDir</value>
</property>

++Ashish