Linux seems to be a favorite OS for supercomputer makers.  There are distributions like SuSE, RedHat, and even CentOS in the mix.    You can browse the Top 500 website and see that about 89+ % of the OS family being used is Linux.

Some supercomputer vendors prefer to customize their own Linux distribution to adapt it to the unique architecture of their respective machines.  For example, for Cray Inc.’s XT6 and XT5 supercomputers, they use a Cray Linux Environment (CLE) that allows the OS to scale to hundreds of thousands of cores.

It’s good to hear that Linux is given the confidence in handling large amounts of data used in solving numerically big problems.  Good job, Linux!