Just an observation but it is kind of interesting from a historical change point of view how much mission critical and core infrastructure is now on Windows based servers if today is anything to go by. Go back 15+ years ago in the SME space at least, Windows was very much the tertiary part of a companies infrastructure with a Sun (Oracle)/RS/AIX/HPUX etc. backend doing the heavy lifting in the main (and on prem). Of course really back in the day it'd be a VME/VMS and dumb terminals, but I digress (and also feel quite old
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).
I know Red Hat (and it's successor flavours) and Ubuntu etc are a thing in Enterprise (my own company has a ton of them for different hardened tasks) but I guess I'm just surprised how many large/multinational companies are now Windows reliant.