Wednesday, February 21, 2007

virtualization: types of hypervisors

From the Wikipedia Definition:

"In computing, a hypervisor (also: virtual machine monitor) is a virtualization platform that allows multiple operating systems to run on a host computer at the same time. The term usually refers to an implementation using full virtualization. Hypervisors are currently classified in two types:

* Type 1 hypervisor
(e.g. ESX Server)
is software that runs directly on a given hardware platform (as an operating system control program). A 'guest' operating system thus runs at the second level above the hardware. The classic type 1 hypervisor was CP/CMS, developed at IBM in the 1960s, ancestor of IBM's current z/VM. More recent examples are Xen, VMware's ESX Server, and Sun's Hypervisor (released in 2005).

* Type 2 hypervisor
(e.g. VM Workstation)
is software that runs within an operating system environment. A 'guest' operating system thus runs at the third level above the hardware. Examples include VMware server and Microsoft Virtual Server."

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