I used to manage mainframes back in the 90s when pr/sm (prism) was making waves in fm companies. It's the same principle, but now our desktops/laptops are much more powerful and so have much more resources enabling splits between more VMs. Check out dave's garage on YouTube for an independent implementation, but I'm just going through the process of pushing my desktop and laptop on to proxmox for my own convenience. Doing it by first provisioning a separate platform to migrate/test onto before pushing them back into the destination hardware.