Google App Engine: When will Microsoft field a competitor?

On April 7, Google took the wraps off of more than many had expected: Not just a hosted database platform, but an entire hosted Web app platform, known as Google App Engine.

Google App Engine, which Google announced at its CampFire One developer event on April 7, as explained by TechCrunch, looks like this:

Google's App Engine is "an ambitious new project that offers a full-stack, hosted, automatically scalable web application platform consisting of Python application servers, BigTable database access ... and GFS data store services."

I've heard rumors that Microsoft is readying a competitive hosted application platform. But more on that in a bit....

The database component of Google's App Engine, known as "BigTable," is aimed at Amazon's SimpleDB -- and Microsoft's SQL Server Data Services (SSDS).

Or maybe not...

As Roger Jennings notes over on his Oakleaf Systems blog, Google's BigTable (and Amazon's SimpleDB) are really not a whole lot like Microsoft's SSDS. As Jennings blogged this past weekend:

"My conclusion based on the Bigtable paper and SimpleDB documentation: Bigtable's architecture and implementation have more in common with Amazon's Simple DB than either database has with SSDS ... Bigtable and SimpleDB aren't relational database management systems (RDBMSs); both resemble multidimensional indexed maps of attribute/value pairs. SSDS attempts to hide the fact that it's an RDBMS (relational database management system)."

When I spoke with Microsoft officials about SSDS at Mix '08, it was hard to get them to explain exactly what SSDS was. As I noted in early March:

"Microsoft officials were reticent to compare SQL Server Data Services to offerings from any competitors. But Gartner Vice President David Smith said the new Microsoft service was comparable to a service like Amazon’s SimpleDB."

SimpleDB, which Amazon released into public beta in December 2007, is a complement and adjunct to the company’s Elastic Computing Cloud (EC2) and Simple Data Storage Service (S3). It allows customers to store, modify and query data hosted in the cloud.

SSDS is just one of a number of developer-focused hosted services Microsoft is readying. Microsoft already has announced it is working on BizTalk Services, which are workflow services that extend the company's BizTalk Server product. Microsoft also has unveiled beta versions of its Synchronization Framework, elements of which which sound an awful lot like the nearly abandoned WinFS (Windows File System).

According to one developer who said he believed Microsoft was close to fielding a hosted app platform: "A hosted workflow engine, with Microsoft's killer tools behind it, could be their big 'cloud' killer service."

Of course, the big question is when the app-platform team at Microsoft will be able to deliver a test build of a cohesive service like Google's App Engine. That team seems to have its hands full, at the moment, finishing off SQL Server 2008, as well as building out Microsoft's "Oslo" SOA infrastructure.

Anyone have more specifics -- or even educated guesses -- to share on what Microsoft is doing to compete with Google's App Engine? I'm also curious how much of this kind of solution Yahoo has in place... or up its sleeves....