What sysadmin, when presented with a VM system, hasn't tried to boot up a second level system (and then a third level system, and a fourth level system, etc.). And, what sysadmin hasn't gotten confused at which VM level they're on and issue the CP SHUTDOWN command? I know I certainly have. Luckily, it was a "Personal" mainframe I was on, so I only shot myself in the foot. Does anyone remember those IBM P/370 machines? (Ok, so it's been a couple of decades ago. Still, they were pretty darned neat.). I lusted after one of the P/390s, but never could acquire one.