Above the hypervisor are the guest operating systems, also called virtual machines (VMs).

系统管理程序之上是客户机操作系统，也称为虚拟机(VM)。

youdao

With no additional customization, users can create XEN virtual machines running modified, highly tuned, para-virtualized guest operating systems for optimal performance.

用户不需要定制就可以创建 XEN 虚拟机，可以用它们运行经过调优的虚拟化访客操作系统，产生出色的性能。

youdao

The software treats various versions of Windows as "guest" operating systems that are run on virtual machines launched within the Mac OS operating environment.

FORBES: Magazine Article