This is the case for some . Like the Tandem Nonstop series. (Now part of Hewlett Packard Enterprise) I had a contract with a 9/11 call handler for a while. The

This is the case for some . Like the Tandem Nonstop series. (Now part of Hewlett Packard Enterprise) I had a contract with a 9/11 call handler for a while. They had one of them (or possibly more). On display of sorts through a window of bulletproof glass. The IBM Z series does not allow hot swapping the CPU and I dont believe it ever did. The parts on the Z Series are super easy to replace. All in nice components sitting on a rails to yank in or out.