Please bear with the lack of details, as my (very limited) VMS experience involved an offline system which never broke, but: it is amazingly tolerant of hardware failures, I recall sitting slack-jawed over the AlphaStation manual after learning you could hot-swap just about anything - including CPU boards!
Granted, that is as much (if not more!) a feature of the hardware architecture than the OS - but amazing still.
I've never heard of an NT box capable of that - maybe the Alpha port could do it? Anyone know?
Fun fact: Windows 2008 R2 and Itanium 2 had lock-step fault-tolerance. (Which is on par with the other "biggies"-- VMS, IBMs OS360/MVS, and HP (nee Compaq Tandem)).
On a more relevant note, I know x86-64 Xeon's can mark bad RAM, disk drives, and network cards, and hot-swap them all out out (and has been able to do so for > 10 years) on most motherboards (it's supported at the OS level for Windows server), not sure if it ever had full CPU failure support though.
Granted, that is as much (if not more!) a feature of the hardware architecture than the OS - but amazing still.
I've never heard of an NT box capable of that - maybe the Alpha port could do it? Anyone know?