Formal Requirements for Virtualizable Third Generation Architectures Virtual machine systems have been implemented on a limited number of third generation computer systems, e.g. CP-67 on the IBM 360/67. From previous empirical studies, it is known that certain third generation computer systems, e.g. the DEC PDP-10, cannot support a virtual machine system. In this paper, model of a third-generation-like computer system is developed. Formal techniques are used to derive precise sufficient conditions to test whether such an architecture can support virtual machines. CACM July, 1974 Popek, G. J. Goldberg, R. P. operating system, third generation architecture, sensitive instruction, formal requirements, abstract model, proof, virtual machine, virtual memory, hypervisor, virtual machine monitor 4.32 4.35 5.21 5.22 CA740707 JB January 17, 1978 11:19 AM 2624 5 2624 2624 5 2624 2624 5 2624 3144 5 2624 1471 6 2624 2298 6 2624 2491 6 2624 2597 6 2624 2624 6 2624 2625 6 2624 2632 6 2624