Direct quote from your link: "Since 2017, every system on the Top500 list of the world's fastest supercomputers has used Beowulf software methods and a Linux o

Direct quote from your link: "Since 2017, every system on the Top500 list of the world's fastest supercomputers has used Beowulf software methods and a Linux operating system." As for accessible by everyone: here is how you can apply for computing time via PRACE, if you work at an academic institution, a commercial company or a government entity located in Europe: https://prace-ri.eu/call/eurohpc-ju-call-for-proposals-for-regular-access-mode-2023-07-07-cutoff/ https://prace-ri.eu/call/eurohpc-ju-call-for-proposals-for-r... In addition to the very large machines that are covered by PRACE, typically there are national calls for access to "smaller" HPC resources, say up to a few million CPU-hours per year. The allocations on PRACE average around 30-40 million cpu-hours. What is explicitly NOT allowed on these machines is typically running jobs that use just a handful of cores. They've paid a lot of money for the fancy interconnect, amd they want to see it used.