Piecing together Microsoft's cloud-computing vision

The term "cloud computing" has become almost meaningless -- being used synonymously for everything from software-as-a-service (SaaS), to platform-as-a-service (PaaS).

But a new white paper, sponsored by Microsoft and written by the always entertaining consultant David Chappell, provides more clues aboutwhat the Softies are planning to unveil at this October's Professional Developers Conference. For anyone looking to understand how and where Red Dog, Zurich, BizTalk Services and SQL Server Data Services (SSDS) all fit together, the 13-pager is worth a read.

Chappell, who provided an insightful talk at TechEd in June on Microsoft's "Oslo" initiative (while managing to tread safely through a minefield of non-disclosure agreements) has done the same thing with his new paper, "A Short Introduction to Cloud Platforms: An Enterprise-Oriented View." He doesn't reference any of the aformentioned codenames by name.

But Chappell does provide a taxonomy for an application platform that's useful when trying to piece together the various Oslo components under development. As Chappell outlines it, first there's the foundation -- platform software on a machine, including a base operating system, storage and standard libraries. Next up is infrastucture services (remote storage, integration services, identity services, etc.). And then there are application services -- the services out of which cloud applications are built.

Chappell cites Amazon's Elastic Compute Cloud (EC2) as the best-known example of a cloud OS today. He explains:

"By far the most well-known example of an operating system in the cloud today is Amazon’s Elastic Compute Cloud (EC2). EC2 provides customer-specific Linux instances running in virtual machines (VMs). From a technical perspective, it might be more accurate to think of EC2 as a platform for VMs rather than operating systems. Still, a developer sees an operating system interface, and so viewing it in this light makes more sense here.

"Each development team is free to use whatever local support it likes in this VM—Amazon doesn’t care. The creators of one application might choose a Java EE app server and MySQL, for example, while another group might go with Ruby on Rails. EC2 customers are even free to create many Linux instances, then distribute large workloads across them in parallel, such as for scientific applications. While the service EC2 provides is quite basic, it’s also very general, and so it can be used in many different ways."

Microsoft is known to be working on a low-level "cloud OS" that is code-named Red Dog. Red Dog is expected to harness the power of multiple, distributed systems in a datacenter so that cloud apps can be more scalable and easier to write. And Zurich -- Microsoft's extension of .Net to the cloud -- is part of Redmond's solution here, as well.

At the highest level, Zurich is Microsoft's Software+Services platform: This is what Microsoft and third-party apps cloud applications will be built upon. It's akin to platforms like Salesforce.com's Force.com and Google's AppEngine platform -- both of which are mentioned in Chappell's paper. He never directly mentions Zurich, though. This is as close as he gets:

"Microsoft also provides local support for applications in the cloud as part of its CRM Live offering. Based on the Dynamics CRM platform mentioned earlier, this technology targets data-oriented business applications, much like Force.com. And like both Force.com and AppEngine, it includes both run-time application support and a data store. Microsoft has also talked about its plans to go further in this area, with a platform that will support standard .NET development languages and tools. The intent, Microsoft says, is to allow portability of both applications and developer skills between the company’s on-premises foundation and its cloud foundation."

On the infrastructure services side, Microsoft already has a bunch of pieces in place. SSDS is Microsoft's equivalent to Amazon's Simple DB storage service. BizTalk Services, a version of which is in beta, provides integrated workflow and integration. Windows Live ID provides federated identity services.

Application services are the most fuzzy and ill-defined piece of the cloud puzzle. In his white paper, Chappell groups lots of things in here -- Live Search, Virtual Earth, Windows Live Photo Gallery, Windows Live Contacts, etc.

I'm still puzzling over how a couple of Microsoft products and technologies fit into this matrix. What about Live Mesh and the Mesh FX (Framework) that Microsoft mentioned briefly when it rolled out its Mesh vision earlier this year? Is Live Mesh simply an application service that runs on top of Red Dog/Zurich?

And whatever happened to the obscure "xRM" -- the "Titan" platform-as-a-service offering from the Microsoft Dynamics CRM team? Chappell mentions that Microsoft was working on such a beast (though, again, without calling it out by name) in his section on Force.com and AppEngine. Is the xRM technology still around? If so, how does it fit in with Red Dog/Zurich/Oslo et. al.?

Anyone know of other pieces of Microsoft's cloud-computing puzzle that we might see at the PDC in October, if not before?