virtual machines

Virtualization, and the support of virtual operating systems, has been a part of IT for a very long time. The concepts are pretty simple; I/O has been much slower than main memory so actions taken by the processor have happened more quickly than actions directed at storage. This resulted in a lot of processor wait time and processor time was viewed as expensive; what could we do while we waited? Initially this lead to the creation of a number of partitions all sharing virtual storage (VS) so much so that it wasn’t unusual to find large systems running five, seven, twelve and more partitions that, in the case of IBM mainframes, broke processing down into online and batch.