Biggest Linux Supercomputer?

Claes Månsson writes "While looking at faster super computers than the recently announced avalon, I came across this. The CPlant Cluster at Sandia National Laboratories (ranked #98 on the TOP500 list), is "using Linux as base OS. Each resource node runs a customized version of Linux." It seems that it is not only the beowulf style super computers that are making use of Linux... "