The Top 500 Project lists the 500 fastest supercomputers in the world biannually. They have released this year’s list and in terms of the operating system used it is Linux all the way with more than 90% of the supercomputers running on Linux.
It is not surprising that Linux is generally preferred in supercomputers but the percentage (91%) is surprising.
Hers is a diagrammatic representation of the data. The larger boxes represents more powerful systems.
You can view this diagram and others like country-wise breakup , manufature-wise breakup etc in an interactive form at http://news.bbc.co.uk/2/hi/technology/10187248.stm.
In case you want the actual numerical breakup of the Operating System Family, here it is:
And here is the Operating System breakdown: