First, a bit of history. In the early 1970s, IBM had two separate operating system development teams competing for the future of the mainframe. The establishment - represented by MVS - offered continuity from the age of the 360.
Another group of trendy virtual machine enthusiasts were quietly working on VM/370 - an exciting route away from the unwieldy monolith that MVS had become. The VM team even had stylish enamel button badges made with the legend "VM Bigot".
IBM's VM/370 was not the origin of virtualization - that accolade probably belongs to its precursors CP-40 and CP/CMS (interestingly, an early example of open source).
Even in the 1970s anyone with any sense could see the advantages virtualization offered. It separates applications and operating systems from the hardware. With VM/370 you could even run MVS on top - along with other operating systems such as Unix. The irony was it took a long time for VM/370 - now called z/VM - to overtake MVS and take its place in IBM's product range. By the time it did, it was largely hidden from view - as such "deep" technology ought to be.
There is a lesson here for the new breed of "VM Bigots" (badge pictured). Virtualization is not a product - it is an enabling technology and as such it should be hidden from view. One wise commentator has already spotted this. Others who see virtualization as something more than a useful technology would do well to learn from history.®