Virtualization Concepts

Hypervisor-based partitioning

Type-1 Hypervisor

Type-1 hypervisors have the function implemented as part of the operating system software or the hardware firmware on a given hardware platform. When the hypervisor is implemented as part of the operating system, this operating system providing the hypervisor function is called the “host” operating system. The operating system running inside a virtual machine (VM) created on the host system is called the “guest” operating system.

z/VM is an example of a Type-1 Hypervisor. Some other examples are the Xen OpenSource Hypervisor, VMWare ESX Server, Virtual Iron, and ScaleMP.

Type-2 Hypervisor

Type-2 hypervisors are hypervisors running on a host operating system as an application. In this case, the host operating system refers to the operating system on which the hypervisor application is running. The host operating system runs directly on the hardware. The operating system running inside the virtual machine (VM) created using the hypervisor application is the guest operating system in this context.

VMWare GSX, Microsoft® Virtual Server, Win4Lin, and UserModeLinux are some examples of this type of hypervisor.