So far, most of the talk about Ubuntu convergenceCanonical's effort to make Ubuntu Linux run on smartphones and tablets as well as traditional PCs—is about hardware compatibility. But what about building the applications that Ubuntu mobile users will need? That's a problem Ubuntu developers are now beginning to solve, too.

No matter how well Ubuntu works as an operating system platform on mobile devices, it won't be very useful without an accompanying app ecosystem. And while Canonical has worked hard to ensure that many of the core Ubuntu applications—such as the Unity interface and a new email program—will work well on the tablets and smartphones that the company is targeting as the next frontier of the Ubuntu world, it can't, on its own, create all the apps that users will need for a complete experience on Ubuntu-based mobile devices. For that, Canonical has to rely on third-party developers.

Fortunately, a vast universe of mobile-friendly apps already exists in the form of those written for Android, Ubuntu's Linux-based cousin. Unfortunately, Android and Ubuntu aren't closely enough related for most Android apps to be ported easily to Ubuntu.

Recently, however, Ubuntu developer Michael Hall outlined a potential solution to this conundrum through an app-conversion tool he has begun developing called NDR. Unlike similar software designed to make code written for one platform work on another, NDR "doesn't let you run our Android code on Ubuntu, nor does it try to convert your Android code to native code," Hall writes. "Instead NDR will re-create the general framework of your Android app as a native Ubuntu app," providing developers a starting-point from which they can make an Android app run well on Ubuntu with minimal effort.

The details of NDR's inner-workings, which Hall discusses in greater depth on his post, will make sense only to programmers. But for all members of the Ubuntu ecosystem, this sliver of news, which has passed mostly under the radar, is a reminder that making Ubuntu useful on phones and tablets requires much more than sorting out hardware-compatibility issues. It also requires the creation of a rich and expansive, mobile-friendly app ecosystem for Ubuntu, which the Ubuntu community would take many years to generate on its own. Yet by providing easy ways to "open the door for high-quality, native Ubuntu app ports from the Android ecosystem," as Hall wrote, NDR, or a tool similar to it, could be a key part of Canonical's "convergence" strategy for Ubuntu.