Operating system virtualization refers to the use of software to allow system
hardware to run multiple instances of different operating systems concurrently, allowing
you to run different applications requiring different operating systems on one
computer system. The operating systems do not interfere with
each other or the various applications. Not to be
confused with operating
system-level virtualization, which is a type of server virtualization.
VMware: The Virtual Desktop, The Virtual Server Virtual computers are often better than real ones. When I was younger and a systems analyst for IBM's System/370 mainframe, all my work centered on virtual machines; thanks to the design of the mainframe hardware, my software never "saw" the real hardware, but merely a VM image, common to all System/370 models, that provided a consistent runtime environment not only for me, but for hundreds of simultaneous user sessions.