There may be a misunderstanding here. If you allow the install CD to create
the system automagicly, yes it uses the whole disk. Notice the work
automagicly,
sometimes the magic goes wrong, or different from what is intended. When it
uses the whole disk it does create two partitions. Root or / and swap,
which is
unformated raw disk space. Usually at least the same size or twice the
size of
memory. On a single user system it is nice to have three partitions, or
more
depending on it use. On my systems I keep only three, / or root, home
mounted
as /home and unmounted swap. I keep root about 8 GB on both my 200 GB laptop
because it has a part of it with windows. On my 40 GB Desktop upstairs I
only have
Ubuntu 10.10 and it again has three partitions. Those being root and
home and
unformated swap. It has been this way for about 6 months now and I have
loaded
Ubuntu's 8.04, 9.04. 9.10, 10.04 and 10.10. I have also loaded Debian,
Fedora, Mepis,
and Suse. Only to go back to 10.10 of Ubuntu. All keeping the same /home
partition.
For each of the loads above I formated root leaving home unformated and
in the
installation portion there is an easy to miss part to mount home as
/home, if left
blank, you will have to do mount it manually, where it will get put into
the mount
table for future use by the system at boot time.