<Dd> These hypervisors run directly on the host's hardware to control the hardware and to manage guest operating systems . For this reason, they are sometimes called bare metal hypervisors . The first hypervisors, which IBM developed in the 1960s, were native hypervisors . These included the test software SIMMON and the CP / CMS operating system (the predecessor of IBM's z / VM). Modern equivalents include AntsleOs, Xen, XCP - ng, Oracle VM Server for SPARC, Oracle VM Server for x86, Microsoft Hyper - V, Xbox One system software, and VMware ESX / ESXi . </Dd> <Dt> Type - 2 or hosted hypervisors </Dt> <Dd> These hypervisors run on a conventional operating system (OS) just as other computer programs do . A guest operating system runs as a process on the host . Type - 2 hypervisors abstract guest operating systems from the host operating system . VMware Workstation, VMware Player, VirtualBox, Parallels Desktop for Mac and QEMU are examples of type - 2 hypervisors . </Dd> <P> The distinction between these two types is not necessarily clear . Linux's Kernel - based Virtual Machine (KVM) and FreeBSD's bhyve are kernel modules that effectively convert the host operating system to a type - 1 hypervisor . At the same time, since Linux distributions and FreeBSD are still general - purpose operating systems, with other applications competing for VM resources, KVM and bhyve can also be categorized as type - 2 hypervisors . </P>

Which hypervisors are installed on top of the host operating system