From time to time, I am greeted with looks of shocked disbelief when a younger employee finds out how much of my employer's business gets done on OpenVMS Alphas and IBM Mainframes. They think it's stupid that we're not running it all on HP servers in the data center.
The thought never occurs to them that it's rock solid, only needs quarterly patching(at most) and has had 20+ years of tweaks that make it fit our needs. We don't need to replace it, yet.
When people really need something that's reliable, there's really no limit to how much effort can be put into producing a system with unfailing integrity and availability.
Take, for example, the lockstep facility on certain IBM processors:
You can take two or more of them, run identical software on them, and compare their output on a cycle-by-cycle basis.
Now, the 750GX series may be a bit out of date in the modern era ... but good luck achieving that level of paranoid system integrity with just about any truly modern system.
One thing that I think they don't teach so well in most colleges is that a system's compute performance is not always the most important measurement of the system's capability.
Not to mention there's VMS clusters with 20+ years of uptime. The systems, especially Alphas, were so reliable that at least one sysadmin forgot how to restart them and had to consult the manual lol. I wish they made a good desktop. I'd have used it and probably lost less work. ;)
Notice how "all systems crashed" from heat except the AlphaServer. That's great engineering, right there. It's why I wish they were still around outside eBay. That plus PALmode: most benefits of microprogramming without knowing microprogramming. :)
The thought never occurs to them that it's rock solid, only needs quarterly patching(at most) and has had 20+ years of tweaks that make it fit our needs. We don't need to replace it, yet.