Comment by cyberax

Linux is not a monolith :)

There was (and still is) a bunch of niche Linux kernels. I remember reading about a team that used Xen to do triple-redundancy with voting for Linux. They virtualized _all_ the non-deterministic IO paths (including rdtsc) and observed the outgoing network packets, ensuring that they are completely identical. I think this was around the mid-2000-s timeframe.

But yeah, it was all super-niche. The consensus now is that you should design your systems to be fault-tolerant and self-recovering, rather than depending on perfect hardware functionality. And for everything else IBM still exists.