AMC Queue has an article by Mendel Rosenblum of Stanford University and VMWare about the return of virtual machines:
Although hardware-level virtualization went from being widely used during the 1970s to near extinction in the 1980s, it has come back in a strong way. The success of VMware’s products in the commercial marketplace, together with recent hardware support for virtualization such as Intel’s Vanderpool technology and extensions to IBM’s Power architecture, indicate that it is a technology just now beginning to be fully realized and that it is here to stay.
Computing trends indicate that the data center of the future will likely include a hardware-level virtualization layer and a control system. Services will run in virtual machines and will be mapped onto available hardware resources. Not only will this greatly ease the management of data centers, it will also ease the handling of new hardware, as well as failed hardware. The failure of a single physical box will reduce the pool of available resources, not the availability of a particular service.
Similarly, virtual machine technology will be used to allow aggressive innovation in the area of system software, providing the ability to maintain backward compatibility. Virtual machines will allow for the support of old applications, as well as the current versions, and will test the deployment of new versions that are all based on the same hardware.
One consequence of Moore’s law of semiconductor growth has been the exponential increase in the performance of computing systems. The overhead of a well-tuned hardware virtualization system is extremely small compared with the performance increase. This means that the computing industry can, for only a few percentage points of performance, realize the huge benefits of hardware-level virtualization. Such benefits include the management of both the hardware and the software that runs in virtual machinescurrently a large expense in modern computing environments.