But is the PDK enough to secure for developers the single user experience for big numbers of Android users that developers crave?

In a "" with the Android team, the packed house of developers had more questions about OS fragmentation than Google had answers.

Asked how the company intended to get Jelly Bean to users faster than it has Ice Cream Sandwich, a staffer said, "We're going to first give you free devices; that's one good way to start." Google is giving free tablets and phones to developers at the event.

One developer asked about the at I/O in 2011 that would ensure that smartphones got regular updates for at least 18 months. The Alliance was a commitment from OEMs to ensure that users of their phones got relevant updates quickly, Google said.

The response was somewhat flippant. "What we said last year is that we would make sure devices got supported for 18 months, but it hasn't been 18 months since last year so we can't prove or disprove if it's working or not," said Dave Burke, Android engineering director.