ABSTRACT

What Is Virtualization? Virtualization is the logical division of a physical machine into multiple virtual machines (VMs), sometimes called guests. The concept of virtual systems came mainly from ideas developed in the 1960s and made into a time-sharing software product called Control/Program Cambridge Monitor System (CP/CMS). CP/CMS became CP-40 and evolved into CP-67, which appeared in 1967. (It also owes something to MIT’s Multics* [1969].)

The development of CP-67 culminated in the announcement of VM/370 on August 2, 1972, along with enhancements to the System/370 range of machines. A nuance that amused me at the announcement was that you could run VM/370 under VM/370 ad infinitum.