[ Thanks to An Anonymous Reader for this link. ]
“Login screens are something that often get overlooked
on a machine because at most we spend a few seconds every day
staring at them. But they are important not only because of the
security they offer, but because of the loading time they can add
to a system boot.
“Canonical has decided it is going to change the login manager
it uses for Ubuntu 11.10 (Oneiric Ocelot) from the Gnome Display
Manager (GDM) to the Light Display Manager (LightDM). This is a
significant change for two reasons. The first is one of size, and
as the name implies LightDM is much more lightweight than GDM.
While GDM consists of around 50,000 lines of code, LightDM only has
5,000 for effectively doing the same job. LightDM is meant to be
very fast meaning it could have a positive impact on boot