Microsoft is seeking to engage enterprise programmers in cloud development by giving them tools that work roughly the same way in the enterprise and in the Microsoft Azure cloud. The upcoming versions of Visual Studio 2010 and .Net 4.0 will provide the first changes to start to implement the dual approach. Behind the tools, an Azure feature, AppFabric, will provide some of the plumbing that will allow the tools to work as expected in the cloud as well as the enterprise.

AppFabric was an understated part of the Azure announcement, getting barely equal billing with the images from NASA's public data base of data from Mars. Attendees were given 3D glasses to view the Martian scenes, eerie reddish landscapes showing up in great depth, an example of the public data that Microsoft will make available via Azure. AppFabric was less graphic.

But AppFabric will be critical to carrying off the Microsoft strategy of applying Windows development skills to the cloud. Through an assembly of mechanisms, it will function as a cloud application server, or provider of services that allow an application to connect up and scale out, as needed. It became available in beta Tuesday and a generally available version is to be delivered sometime in 2010. If a slowdown in the cloud, AppFabric can supply a caching service to an application in the cloud, allowing it to speed up response times and keep the overall application performing adequately. Alternatively, a service level agreement or other rule-based requirements could be enforced automatically.

"From the get go, you want a cloud application to be able to scale up and down, a fabric based underpinning that allows it to organically scale," said Abhay Parasnis, general manager of the Microsoft Application Server Group, in an interview at Professional Developers Conference in Los Angeles.

The rough equivalent to AppFabric in the enterprise environment is the application server, primarily a Java phenomenon as a separate product, which allowed applications to go from serving a handful of users in the enterprise to thousands of simultaneous users on the Web.

Microsoft handled application services by including them in the Windows Server operating system instead of putting them into a separate product, and Parasnis was the supervisor of that application service provisioning.

Now his task to apply the lessons learned to the cloud setting, which is a dramatically different environment, he concedes. Nevertheless, it's a Microsoft goal to allow "all existing investments in tools and technology to apply to the new environment." Microsoft's shift to the cloud will be much more likely to succeed if it continues to command the loyalties of 7-8 million developers who have carried Windows so far into the enterprise.

In fact the application services in Windows Server will be called Windows Server AppFabric in the future. This version of AppFabric makes use of Microsoft's ASP.Net ,its modernized offshoot of Active Server Pages that provides interactive elements on a Web page; Windows Communication Foundation which combined a set of protocols that Windows applications used to communicate with each other and the SOAP Web service protocol into one API; and Windows Workflow Foundation, which uses declarative rules to govern workflow processes.