A significant portion of the 1.6 million square feet covered by the Consumer Electronics Show in Las Vegas last week was dedicated to a bewildering variety of tablet computers from all manner of companies. But whether any of these devices succeed or fail likely rests with two companies without booths at the show: Apple and Google. With the launch of the iPad last April, Apple single-handedly created a viable market for consumer tablets for the first time. Although Windows tablets and BlackBerry's PlayBook were shown at CES, the majority of tablets taking on the iPad will use the Android operating system developed by Google, originally for smart phones. That puts these devices at the mercy of the search and advertising giant, which is still finishing up Android 3.0, designed specifically for tablets. Meanwhile, the goal line could soon shift because Apple is widely expected to deliver a second, improved version of the iPad inside six months.