[Hadoop-common-user] What is IPC classes for???

Hi Ahmad,

Those are the classes used for daemons to talk to each other. Take a look
at what IPC means:

<http://en.wikipedia.org/wiki/Inter-process_communication>

Hope this helps.

Alex

But i want to know if they are used by JobTracker and TaskTracker, or they
are used by DataNode and NameNode. Or is it used by the child
threads that are used for map-reduce to talk to TaskTracker on that machine.

Regards,
Ahmad Shahzad

All of the above. See the packages
org.apache.hadoop.{hdfs,mapred}.{protocol,server.protocol}