This is one of the most interesting stories circulating before the opening today in San Francisco of the Google I/O conference for developers. It seems the search giant will pose a more direct challenge to Amazon’s Kindle Fire than to Apple’s iPad: Google and computer maker Asus will announce a 7-inch tablet that will sell for about $200, Bloomberg reports. The device will run the latest version of the Android operating system, code-named Jellybean. Microsoft beat Google to the punch last week, announcing its own Windows-based tablets — Surface and Surface Pro — each with a more iPad-like 10.6-inch screen. Meanwhile, Amazon is gearing up to launch a revamped Kindle Fire at the end of July, CNET says. Among the changes: it likely will have a camera and a physical volume-control button.