A hypervisor is a software virtualization program that provides a layer of abstraction between operating systems and physical resources on a machine.
管理程序指的是一种软件虚拟化程序，它在操作系统和机器物理资源之间提供了一个抽象层。
2
Moving towards higher abstraction levels and languages, that mapping becomes one-to-many; the number of machine instructions generated from a design level construct rapidly increases.
移动到更高的抽象层次和语言上时，该映射成为一对多，由设计层构造所生成的机器指令的数量快速的增加。
3
They allow the programmer to focus more on "what" than on "how" by raising the level of abstraction; that is, details at the machine level are abstracted away.