What is coming in Hadoop 20.

Cloudera has posted a very nice summary,
http://www.cloudera.com/blog/2009/05/07/what%E2%80%99s-new-in-hadoop-core-020/

The big user visible change is the addition of the new API's for MapReduce where a context object is passed in to the configure, map/reduce and close that contains the jobconf equivalent, the output collector and the reporter and any other data people pack in.

There are some issues with this at present so it is not ready for prime time.

The preparation for the split of MapReduce and HDFS has started and the visible change is that the hadop-site.xml file is now 3 files, core-site.xml, mapred-site.xml and hdfs-site.xml