<P> There are different kinds of virtual machines, each with different functions: </P> <Ul> <Li> System virtual machines (also termed full virtualization VMs) provide a substitute for a real machine . They provide functionality needed to execute entire operating systems . A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine . Modern hypervisors use hardware - assisted virtualization, virtualization - specific hardware, primarily from the host CPUs . </Li> <Li> Process virtual machines are designed to execute computer programs in a platform - independent environment . </Li> </Ul> <Li> System virtual machines (also termed full virtualization VMs) provide a substitute for a real machine . They provide functionality needed to execute entire operating systems . A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine . Modern hypervisors use hardware - assisted virtualization, virtualization - specific hardware, primarily from the host CPUs . </Li> <Li> Process virtual machines are designed to execute computer programs in a platform - independent environment . </Li>

1. list and briefly describe virtual machine monitor (vmm) platforms other than the notable ones