The physical hardware might have a large amount of memory, but the hypervisor might designate only 1gb of that memory for a particular virtual system's use.
物理硬件可能拥有大量的内存，但是虚拟监管系统为特定虚拟机系统的使用只分配了1 GB的内存。
2
Therefore, that virtual system appears to be running on a piece of hardware (that is, a virtual server) with only 1gb of memory.
因此，虚拟机系统看起来好像是在一个只有1 GB内存的硬件(其实就是一个虚拟机服务器)上运行。
3
The mapping of virtualmemory to physical memory occurs through page tables, which are implemented in the underlying hardware (see Figure 1).