Microsoft Hyper-V is a hypervisor-based virtualization system for x64 systems. A free stand-alone version of Hyper-V, called "Microsoft Hyper-V Server 2008" was released in late 2008, which is a variant of Windows Server 2008 "Core" that includes full Hyper-V functionality. other Windows 2008 Server Roles are disabled, and there are limited Windows Services.
Hyper-V supports isolation in terms of a partition. A partition is a logical unit of isolation, supported by the hypervisor, in which operating systems execute. A hypervisor instance has to have at least one parent partition, running Windows Server 2008 or 2008 R2. The virtualization stack runs in the parent partition and has direct access to the hardware devices. The parent partition then creates the child partitions which host the guest OSs. A parent partition creates child partitions using the hypercall API, which is the application programming interface exposed by Hyper-V.