Need info on kernel philosofy

[Giorgio A.]

hi all,
i know this is gonna be the lamest question of the year, but i didn't found
a valid answer elsewhere !
I'm using linux as a sysadmin since slack 3.1, and i've subscribed to this
list about 2 month ago. I'm not a developer, i don't have the knowledge, but
i like to watch at all of your e-mails since it makes me feel like i'm
really following the growing of the penguin ! Only now i discovered that
there're 2 trees, the Alans' and the Linus' (here in alphabetical order :-),
and in these days i saw Linus saying that 2.4.15 is ready to be the result
of a merge between the two trees. Now, i wonder if merging the 2 trees is an
usual thing, so it would be happened also with 2.2 and 2.0 (thing that i
can't knew, since at that time i wasn't subscribed to LKML), or if i'm
taking part of a kind of an historycal event, i.e. the fusion of the 2
kernel trees.

tnx for your answer,
have a nice day!

Giorgio A.

  "in girum imus nocte
            et consumimur igni"