Google said its App Engine will make it easier for developers to build and scale applications rather than focus on system administration and maintenance.

First 10,000 Developers

The preview release is limited to the first 10,000 developers to sign up, each of them restricted to 500MB of storage and what Google described as "enough CPU and network bandwidth to sustain around five million page views per month for a typical app." At some point, Google will charge for additional storage and bandwidth.

The Mountain View, Calif.-based company noted that its App Engine offers a number of advantages. For instance, developers will be able to write code once and deploy and dynamically provision computing resources as needed. "Developers write the code," Google said, "and Google App Engine takes care of the rest."

This arrangement also allows the Google infrastructure to absorb spikes in traffic. The company noted that surging popularity for an application in a developer's own environment can mean reworking entire systems several times a year. App Engine provides automatic replication and load balancing, accommodating one user or one million via Google's "Bigtable" and other infrastructure components.

Developers can also easily integrate with other Google services, so that built-in components like authentication and e-mail can be utilized.

'Pretty Hot Right Now'

Brad Shimmin, an analyst with industry research firm Current Analysis, pointed out that Google's App Engine is much like the application hosting that Amazon provides.

"Amazon has been extremely successful with providing online infrastructure for independent software vendors," he said. He noted that the Amazon model offers services for free up to a certain level, after which there are charges.

Al Hilwa, a program director at IDC, said Amazon and Google are among about 20 companies providing on-demand infrastructure for application development. "It's pretty hot right now," he said.

He said there are a variety of approaches by these providers, with Google and Amazon offering a general-purpose infrastructure. A provider like Salesforce.com, Hilwa noted, has a "more mature" development environment geared to enterprise applications.

Hilwa said what's new about the approaches to running applications in 'the cloud ' is the ability to leverage virtualization , so massive resources at a company can be utilized efficiently.

But, he said, the key to the long-term viability of these arrangements is whether they can provide a minimum, agreed-upon level of service over time.