Michael Armbrust and Armando Fox and Rean Griffith and Anthony D. Joseph and Randy H. Katz and Andrew Konwinski and Gunho Lee and David A. Patterson and Ariel Rabkin and Ion Stoica and Matei Zaharia EECS Department, University of California, Berkeley Technical Report No. UCB/EECS-2009-28 February 10, 2009 http://www2.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-28.pdf Provided certain obstacles