Microsoft’s Chief Executive Officer, Steve Ballmer, dismissed Google’s idea of two operating systems claiming “I don’t really know what’s up at Google” in a QnA session on Tuesday.

CNET News reports that Ballmer’s comments came at the Worldwide Partner Conference where he was addressing questions about Google’s Chrome OS during an on-stage talk with Fortune’s Geoff Colvin. “First of all, I will be respectful,” he said. “Who knows what this thing is. To me, the Chrome OS thing is highly interesting in that it won’t happen for a year and a half and they already announced an operating system.”

Ballmer’s comments come as no surprise. The outspoken CEO is notorious for his on-stage antics and commenting on competitors ideas and products. In November 2008 Ballmer poked fun at Google Android, saying “this is their first phone, they’re not easy,” and “let’s see how they do.” Back in April 2007 Ballmer claimed, in an interview with USA Today, “there’s no chance that the iPhone is going to get any significant market share. No chance.” We all know what happened there.