Features
CP-40 was the first operating system that implemented complete virtualization, i.e. it provided a virtual machine environment supporting all aspects of its target computer system (a S/360-40), such that other S/360 operating systems could be installed, tested, and used as if on a stand-alone machine. CP-40 supported fourteen simultaneous virtual machines. Each virtual machine ran in "problem state" – privileged instructions such as I/O operations caused exceptions, which were then caught by the control program and simulated. Similarly, references to virtual memory locations not present in main memory cause page faults, which again were handled by control program rather than reflected to the virtual machine. Further details on this implementation are found in CP/CMS (architecture).
The basic architecture and user interface of CP-40 were carried forward into CP-67/CMS, which evolved to become IBM's current VM product line.
Read more about this topic: IBM CP-40
Famous quotes containing the word features:
“The features of our face are hardly more than gestures which force of habit made permanent. Nature, like the destruction of Pompeii, like the metamorphosis of a nymph into a tree, has arrested us in an accustomed movement.”
—Marcel Proust (1871–1922)
“Each reader discovers for himself that, with respect to the simpler features of nature, succeeding poets have done little else than copy his similes.”
—Henry David Thoreau (1817–1862)
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—Robert Frost (1874–1963)