In our definition of what constitutes a tablet computing platform, we find that smartphones, too, are tablets in that it can provide us with computing functionality in a slate or convertible form factor with a mobile operating system–which can provide s0me gains in battery life compared to a more power-hungry Windows system, as well as connectivity to the internet. It looks like Android, as a mobile operating system designed by Google, is raising to that challenge. we caught up with Sprint and Samsung at CTIA a few weeks ago in sunny San Diego, California to preview the Samsung M900 Moment, which is an Android smartphone with a sliding QWERTY hardware keyboard. Can this replace your tablet?

While it may not be able to replace a full Tablet PC (a moniker that has survived the Windows XP Tablet PC operating system and since then has been replaced with just a Windows name with tablet functions built-in) setup, a mobile phone with the right set of productivity and fun applications can serve to get the mobile executive through a working day without having to rely on a heavier, larger Windows machine. Some examples of smartphone operating systems that provide touch input include the iPhone operating system (which Apple stresses to be based off of the same OS X operating system), Android, Symbian, and Windows Mobile–the latter two with their resistive touchscreen provide inking functionality and more accurate input via a stylus making them more direct challengers to traditional, Windows-based tablet machines. Another challenger is Linux, which can be found on the Nokia N900.