What is the “Ubuntu” session on the login screen?

Question

Based on the login menu options, I see “Ubuntu 2D” as an option and just “Ubuntu”; can I safely assume that “Ubuntu” is 3D ?

Answer 1

The desktop you see when you first login to Ubuntu, is called Unity. It's a "shell" for Ubuntu. There are two parallel versions of Unity. One makes use of the hardware acceleration in modern graphics adapters in order to provide nice effects. (The dash is transparent in real-time, for instance, meaning that if you open it while you have a video open, then you can see the video through the dash.

Ubuntu 2D, which is really called Unity 2D, does the same things, but without requiring accelerated graphics in your graphics adapter. It still has nice effects, like a transparent dash, but it's not live. That is, they fake it by making a copy of the background and use that to give the illusion of transparency. It works quite well, and because it doesn't make so heavy use of advanced graphics, it's better suited for lower end PCs or computers that do not have hardware accelerated 3D.

Unity is the main shell, used by default, but they're both nice. I'm currently using Unity 2D on a fairly strong computer, just because it's nice. :)

Answer 2

Ubuntu here means the Unity interface with its launcher, panel etc. Unity relies on hardware accelerated graphics.

There are computers without hardware accelerated graphics, they cannot use nice visual effects. Unity doesn't work on such machines, so there is Ubuntu 2D, or Unity 2D, which is very similar to the standard Unity interface, but doesn't require hardware accelerated graphics.

Answer 3

The login menu options are:

Ubuntu

for Ubuntu 11.10 + Unity (with advanced 3D features)

Ubuntu 2D

for Ubuntu 11.10 + Unity-2D (without).

So, YES, you are correct.