Resolution: *The physical host running the virtual machine is called the host, i.e., the Host Machine, and the operating system that the host installs and runs is called the host operating system, i.e., the Host OS. Run The virtual machine on the host is called a guest, or Guest Machine . The operating system that the virtual machine runs on is called the guest operating system, or Guest OS . Located at Host Between the Machine and the Guest Machine is the core of all virtualization technologies - the hypervisor, which can also be called VMM . *In the physical architecture, the host has only two layers, namely the hardware layer Host Machine and the operating system layer HostOS, and the application is installed on the Host OS, while in the virtualization architecture, the host is divided into three layers, the hardware The Host Machine, which is the hypervisor, and the Guest Machine and its operating system, Guest OS, are installed in Guest OS. You can create and run multiple guest machines on a single host machine. *Guest machine and VM in the rest of this textbook refer to virtual machines.