Miller's employer shut down those VMs at the end of the working day to free up resources for overnight jobs. He therefore wrote a cleanup routine that removed the drives and backed up their contents. This story took place in 1981, a time when it was possible for code written by a 21-year-old to go into production without much scrutiny.
Blackbox Hosting has consolidated storage from two full racks down to just 8U of rack space following migration to Everpure FlashArray hardware, achieving a 10:1 data reduction ratio and an 85% reduction in power utilization.
I recently wrote about my migration away from VirtualBox to KVM/Virt-Machine for my virtual machine needs. I've found those tools to be far superior (albeit with a bit more of a learning curve) than VirtualBox. Since then, however, I've found another method of working with KVM (the Linux kernel virtual machine technology), one that not only allows me to create and manage virtual machines on my local computer, but also from any machine on my LAN. That tool is Cockpit, which makes managing your Linux machines considerably easier.