It’s probably mostly legacy systems for things like industrial automation.
You can actually still buy industrial motherboards with ISA and PCI slots, for both older CPUs (like the Pentium 4) and newer CPUs (like modern-ish Core i3/i5/i7). There’s also clone CPUs that behave the same as older ones.
A lot of industrial systems are big, expensive, last a long time, and were designed for use with particular hardware, which is why there’s a pretty decent market for clones of old hardware.
Having said that… I’m not sure they’d use a newer operating system on these systems. The OS they run is likely 20 years old too. So… To answer your question, I’m not sure. Retro hardware enthusiasts tend to use an OS from the same time period.
Aside from bragging rights… is there a reason why someone would still be working on a Pentium 4?
It’s probably mostly legacy systems for things like industrial automation.
You can actually still buy industrial motherboards with ISA and PCI slots, for both older CPUs (like the Pentium 4) and newer CPUs (like modern-ish Core i3/i5/i7). There’s also clone CPUs that behave the same as older ones.
A lot of industrial systems are big, expensive, last a long time, and were designed for use with particular hardware, which is why there’s a pretty decent market for clones of old hardware.
Having said that… I’m not sure they’d use a newer operating system on these systems. The OS they run is likely 20 years old too. So… To answer your question, I’m not sure. Retro hardware enthusiasts tend to use an OS from the same time period.