Microsoft has made changes to its licensing model for Windows Vista to meet the needs of enterprise customers in the finance and government sectors using bleeding-edge technologies.

The Redmond, Wash.-based software giant will announce April 2 a subscription license called Windows Vista Enterprise Centralized Desktops, which allows customers to use Windows in virtual machines centralized on server hardware.

It is also giving its Software Assurance customers using Windows Vista Enterprise the license right to use Vista on diskless PCs—essentially machines without hard drives.

Let Your Voice be Heard! Vote on the Most Significant New Product Introductions in the Channel. Click here to fill out our online ballot.

At the same time, Microsoft is enabling its OEM partners to ship those diskless PCs.

"This is a new kind of form factor, and we are enabling our OEM partners to do this, and we expect to see some of them making this new form factor available over the upcoming months," Scott Woodgate, director in the Windows Product Group, told eWeek in an interview.

The move is also Microsoft's response to requests from those customers to open new licensing scenarios for Windows Vista so that they can take some very nascent architectures around the centralization of Windows into their production environments, he said.

Resource Library:

Technology has improved over the past five years, making these nascent solutions, such as fast networking—a key enabler behind the diskless PC—and virtualization, a technology enabling the Vista Enterprise Centralized Desktop, at least viable, he said.

The licensing rights for diskless PCs will be included in Windows Vista Enterprise on April 2. "So this is added value for all exising Windows Vista Enterprise customers. But we don't expect everyone to run and take their hard drives out, but this is added value for the diskless PC at no additional fee," he said.

With regard to Vista Enterprise Centralized Desktops, which is Microsoft's licensing for enabling Windows to run on server hardware in virtual machines, there are two possible access devices: the PC and the thin client.

Microsoft CEO Steve Ballmer says Vista will spur a wave of innovation. Click here to read more.

PCs will be enabled through Software Assurance under an annual subscription, while the thin client will also be priced under an annual subscription.

A small set of early-adopter enterprise customers in the finance and government sectors has already indicated their desire to go ahead and take advantage of these architectures, he said.

"We tried to be very flexible in how this set of customers can deploy Windows in virtual machines on server hardware, such as the scenario where a virtual machine is created in the morning when a user logs in, is provisioned and then deleted in the evening," he said.

"The annual subscription gives customers the ability to install an unlimited number of copies of Windows for use with that licensed device, and run up to four of them at once," Woodgate said.

An example of this would be a trading broker who has a single subscription. His single PC can have four monitors, each of which has a virtual machine desktop in it.

"This is significant as it means that users can now install as many copies of Windows as they want on any server hardware. They can be moved from one server to another, they can be stored on a storage area network or Network-Attached Storage—there is a lot of value there—as well as being able to have up to four of these running for the access device," he said.

The move now opens the door to dynamic scenarios for those customers focused on management and who wanted to reduce the cost of this and the number of images they stored, and take advantage of partner software that allowed them to provision more dynamically, he said.

To read more about the six Vista migration tools Microsoft rolled out, click here.

"What is different here is that the technology continues to evolve and enterprise customers are looking to take advantage of relatively new technologies and to try out Windows in some new deployment models," Woodgate said.

"So, with Vista, we are making the licensing more flexible so as to enable our customers to choose the architecture in which they want to deploy Windows, and also to prove just how valuable these scenarios are in the enterprise," he said.

The typical user for these would be in the government and in the finance industry, where customers were working with very sensitive information that they wanted stored on a storage-area network device rather than a hard drive, and which was then streamed into the PCs memory.

That PC would be booted with a piece of third-party software that is added to Windows, and which finds the image on the network and streams the Windows file, the same way a local hard drive would, into the memory of that PC, he said.

That PC gave the user the full, rich-client perspective, with 3-D graphics and the like, but was not mobile. "The experience is lost when connectivity to the network is ended. So this is most suited to those 'always connected' scenarios," Woodgate said.

With regard to Vista Enterprise Centralized Desktops, which is Microsoft's licensing for enabling Windows to run on server hardware in virtual machines, there are two possible access devices: the PC and the thin client, both of which will be enabled.

Click here to read more about Microsoft's virtual hard disk program to speed up software testing.

While Woodgate declined to give specific pricing, he said this would be based on the number of thin and rich devices, while a server operating system and virtualization stack were required, either Microsoft's offering or a competitor's.

In the case of the PC, this will be enabled through Software Assurance under an annual subscription, while the thin client will also be priced under an annual subscription.

Click here to read more about the roadmap for Windows Server Longhorn.

Asked how VECD compared to Terminal Services, which provides desktops for users running Windows server, among other things, Woodgate said that Terminal Services used one copy of Windows Server in sessions, and scaled at about 10 times more than running VMs inside a virtual machine stack.

"So, with VECD, I would be spending up to 10 times as much on hardware to support the same number of users as I would on Terminal Services, which is a great alternative for those price sensitive, non-early adopter customers," he said.

Check out eWEEK.com's for Microsoft and Windows news, views and analysis.