I took a closer look at the Motorola Atrix on display here at Mobile World Congress. This is a smartphone built on NVidia’s Tegra 2 dual-core chipset. I’m interested in the concept as much as the device. Instead of carrying a laptop and a smartphone, you use the smartphone alone when out and about, or dock to a laptop-like screen and keyboard when at a desk. The dock has its own 36Wh battery so you are not tied to mains power.

The Atrix has a few extra tricks as well. HDMI out enables HD video. An audio dock converts it to a decent portable music player.

The smartphone also morphs into a controller if you use Motorola’s alternative dock, designed for fully external keyboard and screen.

It is a compelling concept, though there is a little awkwardness in the way Motorola has implemented it. The Atrix has two graphical shells installed. One is Android. The other is a an alternative Linux shell which Motorola calls Webtop. While you can freely download apps to Android, the Webtop has just a few applications pre-installed by Motorola, and with no official way to add further applications. One of them is Firefox, so you can browse the web using a full-size browser.

The disconnect between Android and Webtop is mitigated by the ability to run Android within Webtop, either in its own smartphone-sized window, or full screen.

Personally I prefer the idea of running Android full screen, even though it is not designed for a laptop-sized screen, as I do not like the idea of having two separate sets of apps. That seems to miss the point of having a single device. On the other hand, Webtop does enable non-Android apps to run on Atrix, so I can see the value it adds.

Leaving that aside, I do think this is a great idea and one that I expect to become important. After all, if you do not think  Tegra 2 is quite powerful enough, you could wait for some future version built on the quad-core Tegra 3 (name not yet confirmed), which NVidia says is five times faster, and which may turn up in Smartphones late in 2011.