Well you’re not half wrong, at least the LUMI supercomputer, current nr. 9, runs Cray SUSE Linux Enterprise Server with minimal kernel daemons to reduce OS jitter on the compute nodes.

Thought I would mention Guix. I don’t know about using it as an OS but just the package manager is so nice to build reproducible software environments (although disclaimer I discovered this myself a few weeks ago). At least as close you can get without including proprietary hardware drivers. Building MPI applications on my laptop and moving them to an HPC cluster with full performance feels like magic.

In one discord channel my alias is Bread due to an old joke when we played monster prom. Im loving these bread themed memes.