Open-source programs across the board - the Apache Web server, the Perl programming language and the GNU development tool set, to name a few - are gaining legitimacy as a business platform.
The Cascalog system has combined the Cascading system for abstraction of advanced data processing on Hadoop and other systems, the Datalog declarative programming language that is well suited for expressing database queries in an abstract form, and the Clojure language to create a declarative language for queries that can be run on Apache Hadoop.