Linux虚拟机高手进来帮忙看看！谢谢

这是段英文资料：
In general,virtualization environments can be classified into threeclasses. The first class is the system virtualization with
the virtual machinemonitor(VMM) inside the host system.With this type the virtual machine(VM) simulates the complete
hardware, allowing an unmodified operatingsystem(OS) for a completely different CPU to be run. The second class of
virtualization is also a type of system virtualization,but in contrast to the previousone,theVMMis underneath the host
OS.Thus,the VMM runs directly on the hardware.In general this allows multiple OS to run,unmodified,at the same time.
The third class of virtualization is the operating system-level virtualization. It virtualizes a physical server at the OS
level,enabling multiple isolated and secure virtualized servers on a single physical server.The guest OS is the same OS as
the host system,since the same OS kernel is used to implement the guest environments.

我想问问大家，上面提到的三种虚拟机的具体区别是什么样子的啊？一般用的虚拟机，比如windows下用的
VMware，这个属于上面所提到的哪种啊？