The November list of the top 500 supercomputers in the world, released a few days ago <https://top500.org/lists/top500/2023/11/> has, at number 3, a machine called “Eagle”, which is apparently part of Microsoft’s Azure cloud. Looking into the details of this <https://top500.org/system/180236/>, the OS is listed as “Ubuntu 22.04”. And there is another Microsoft-based super at number 15 <https://top500.org/system/180171/>, obviously older because its OS is listed as “Ubuntu 20.04”. And at number 23 <https://top500.org/system/180024/>, we have one running “Ubuntu 18.04 LTS”. Then a few more, even older, down in the 50s, all on Ubuntu 16.04 LTS. Conclusion: they won’t even use their own Windows-based Hyper-V virtualization architecture on high-performance installations. The ARM-based Fugaku machine, which was top of the list not so long ago, has dropped to number 4. Apart from that and two IBM POWER-based entries, the rest of the top 10 is currently all x86-based.