Microsoft has created two new enterprise deployment options for Windows Vista to enable diskless and virtual desktop systems. 

The options are available only for Windows Vista Enterprise, and are limited to enterprises subscribing to Microsoft's Software Assurance programme.

The first change enables the use of the operating system in so-called diskless PCs. This allows enterprises to use a centralised storage facility to save and run the operating system for desktop computers.

Centralising storage cuts the cost of managing desktop systems and increases security.

Microsoft's previous licensing system did not allow Vista to run from a shared storage pool. Customers did not usually ask for the option, however, because networking technologies lacked the bandwidth to enable such applications.

The second licensing change allows companies to run Vista in an even more centralised way through the use of virtualisation on server hardware.

Where a diskless system still requires a CPU in the client computer, Microsoft's Windows Vista Enterprise Centralized Desktop structure allows the software to run with even less overheads on a PC, laptop or thin client.

Microsoft expects that the two programmes will appeal especially to companies in highly regulated industries. But the firm warned that the underlying technology is still relatively young.

"We think that only a select few customers are planning to broadly implement these centralised desktop models today," said Scott Woodgate, director of Microsoft's Windows Business Group.

"The customers that are exploring these scenarios are early adopters, and they will help prove out the usefulness of centralisation over the next few years.

"The changes we are making enable them to do that and to see whether their expected benefits pan out in production."