The technological state of the art at the backend is a circle. You don't have to squint that hard to see the similarities between a hypervisor running hundreds

The technological state of the art at the backend is a circle. You don't have to squint that hard to see the similarities between a hypervisor running hundreds of VMs and a mainframe running hundreds of batch jobs. The difference is just that the mainframe is usually (but not always) co-located with the bank. But small bank branches might completely lack mainframe systems on their own.