Intel's recent announcement that within a few years its 32bit processors will include support for virtualised computing took the industry by surprise.

Virtualisation of computer hardware enables a single computer to run several operating systems concurrently.

Martin Reynolds of analyst company Gartner commented, "This is the first time Intel has spoken publicly about this technology. It's very important, quite unexpected and very exciting." Though Intel has disclosed few details, it seems the new technology will be delivered in about five years' time, and could enable large grid computing projects, where desktop PCs could be put to work running grid software - perhaps after the PCs' regular users have finished for the day.

Processor virtualisation has been a common feature of mainframes for many years. For example, a single IBM mainframe can run several thousand instances of Linux at the same time.

Similar capabilities are also available in high-end Unix systems - for example, in Sun's high-end E10000 and related servers, and also in HP's Superdome server. However, while IBM mainframes can run several operating systems on a single processor, the high-end Unix systems must dedicate at least one processor to each operating system. State-of-the-art virtualisation systems enable resources, such as processors and RAM, to be adjusted without interrupting the virtual operating systems. Currently such facilities are available only with the high-end Unix operating systems, but they are likely to be added to other products in the near future.

Diane Greene, chief executive of virtualisation specialist VMware, predicted that Intel's "Vanderpool" virtualisation technology would make virtualisation ubiquitous Intel has already shown that Vanderpool enables a single PC processor to run several operating systems. In this regard Vanderpool would seem to have much in common with VMware's virtualisation products, which are widely acknowledged as the market leaders in PC virtualisation. But, given that VMware has produced excellent virtualisation tools without requiring specialised hardware features in processors, some observers wonder precisely what Intel would bring to the table.

Edouard Bugnion, VMware's chief architect, said, "The Intel architecture is actually quite difficult to virtualise. Vanderpool is about making it easier to do, and therefore more efficient." He said the lack of chip-level support for virtualisation means VMware's ESX Server operates with an overhead of about 12 to 15 percent.

However, much of the value of VMware's products comes from the software supplied for managing virtual machines. For example, VMware is about to launch its VMotion add-on, which will enable a virtual machine to be migrated from one server to another without interrupting users. Although Intel has said that Vanderpool will be a combination of hardware and software, when pressed on the point, Mike Fister, general manager of Intel's enterprise platforms group, said, "Vanderpool is the hardware part of the virtualising technology."