I recently installed Ubuntu on an older PC with 1GB of RAM and 80GB of hard drive space, so I wanted a lightweight desktop interface. I chose XFCE, since it is both lightweight and usable, and I have used it extensively. You can get Ubuntu pre-made with XFCE (xubuntu), but there are some disadvantages. The ISO is slightly too large to fit on a CD, and it comes with a lot of applications that I don’t need. Instead, I installed Ubuntu from a minimal CD and then used apt-get to install XFCE and the LightDM display manager. I learned that a couple of extra steps must be taken to get XFCE to play with lightdm. I got the error “can’t find session ubuntu”. Don’t bother changing the .dmrc file in your home directory; this file is overwritten every time lightdm starts! I configured lightdm to use an XFCE session with the command:
/usr/lib/lightdm/lightdm-set-defaults --session xfce4-session
I then got the error “can’t find session xfce” until I realized that I had to install another package to get the xfce4 session file:
apt-get install xubuntu-default-settings
That was a lot more trouble than it had to be, but I now have a responsive Linux GUI running in 1GB of RAM that consumes only 2.2GB of hard drive space.