Yahoo's got three more universities using its cloud supercomputer cluster, also known as M45 and operational since November 2007. Berkeley, Cornell and the University of Massachusetts at Amherst will join Carnegie Mellon in conducting large-scale systems software research and exploring new applications that analyze Internet-scale data sets ranging from voting records to online news sources.

Carnegie Mellon has been using it for over a year, resulting in the publication of more than two dozen academic papers.

The cluster has approximately 4,000 processor cores and 1.5 petabytes of disks.

Carnegie Mellon says it gives it more access to data on the Internet and has let it compare the performance of the open source Hadoop file system to other parallel file systems.