As you may be already aware, Ubuntu 11.04 “Natty Narhwal” will have Unity as the default interface. Unity in Natty is powered by Compiz and that will requires a graphics card capable of 3D acceleration. So, there were apprehensions that the new interface will not work with older hardware. It was suggested (and generally believed) that in the older hardware, it will fall back to the normal panel based interface.
This question was raised in Ask Ubuntu and none other than Mark Shuttleworth himself answered it. According to Shuttleworth, there will be a 2D version of Unity for those systems which are not capable of 3D acceleration. He also pointed to a blog post by Bill Filler, Software Engineer and Engineering Manager at Canonical, for more details.
Curiously, the blog post has been removed now. Did Filler jump the gun on this one? We do not know yet.
Anyway, according to the blog post, the 2D version of Unity is implemented using Qt/QML. Filler also noted that the 2D version is important not just for the older computers but many ARM devices as well.
This is what Bill Filler wrote:
Unity 2D’s main goal is to provide a Unity environment on hardware platforms that don’t support Unity’s Open GL requirements. Many ARM platforms fall into this category, so Unity 2D expands Unity’s goodness to a whole new set of platforms.
The software is implemented using Qt/QML for the UI portions of Unity, while utilizing the existing Unity core components, like indicators, bamf, dee, uTouch and places.
This will ensure that the Ubuntu desktops maintains uniformity and should come as good new to many.