既然我们已经知道机器中都有什么了，那么我们需要看一下这些资源中哪些分配给了控制台，哪些分配给了虚拟机。
Now that we know what is in the machine, we need to see which of these resources are allocated to the console and which ones are allocated to the virtual machines.
还允许虚拟机可靠地向主机机器同步它的内部时钟。
It also allows your virtual machine to reliably synchronize its internal clock to the host machine.
有24个或更多的物理主机的节点平均每台物理机承载11个虚拟机，同时有10个或更少的机器的节点每台物理机承载的虚拟机几乎翻番至20。
Sites with 24 or more physical hosts have on average 11 VMs per physical machine, while sites with 10 or fewer machines almost double this to 20 VMs.
您可以使用真实的机器来完成这两个实验，但是使用虚拟机更加方便。
You can use a real machine to do these experiments, but you may find it easier or more comforting to use a virtual machine.
例如，可能希望进一步控制虚拟机到物理机器的映射，或者希望更确定地把IP地址分配给虚拟机。
For instance, you might want more control over the mapping of virtual machines to physical machines, or you might want to be deterministic about the assignment of IP addresses to virtual machines.
如图7所示，我们选择networkaddresstranslation (NAT)，因为它允许虚拟机访问连网的资源，而不必向其他网络机器暴露它。
As shown in Figure 7, we chose network address translation (NAT) because it allows our virtual machine to access networked resources without unnecessarily exposing it to other network machines.
Purdy解释说，过去的客户使用内堆存储，在每台机器(假设60g内存)上运行许多虚拟机，在集群中使用自己的内存。
Purdy explained that in the past users of on-heap storage would have to run many VMs per machine (assuming it has 60gb of memory) to make use of all its memory in the cluster.
P - code是一种机器语言，运行于虚拟机而不是实际硬件。
P-code is a machine language that is executed in a virtual machine rather than in actual hardware.
System/390架构支持机器的完全虚拟化，甚至包括只能在为虚拟机创建的沙箱中运行的“特权”指令。
The System/390 architecture allowed complete virtualization of the machine, including even the "privileged" instructions that simply ran inside the sandbox created for them.
目前虚拟机技术广泛应用于代码移植、跨平台计算和模拟硬件机器等领域。
The technology of virtual machine is widely applied in many fields, such as code transplanting, cross-platform computing, and hardware simulation.
比如，在一台物理机器上运行的虚拟机，假如出现了资源溢出的情况，就会被重新定位到另一台拥有空闲资源的，且对最终用户透明的机器上去。
For example, virtual machines that are running out of resources on one physical machine can be automatically relocated to new hardware with minimal disruption and end user transparency.
缺点：使用一个“虚拟机”来运行可移植的字节码而非本地机器码，程序将比真正编译器慢。
Disadvantages: Uses a "virtual machine" to run portable byte-code rather than native machine code, so apps are slower than true compilers.
它是由国际商用机器公司(IBM)，但与ibm的其他主机的操作系统、虚拟机。
It was developed by IBM, but is unrelated to IBM's other mainframe operating system, VM.
它是由国际商用机器公司(IBM)，但与ibm的其他主机的操作系统、虚拟机。
It was developed by IBM, but is unrelated to IBM's other mainframe operating system, VM.
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