Questions about installing another version of Linux on second drive

[Gary Nielson <gary garynielson com>]

Hi, I am running Redhat 6.2 on a machine with two IDE drives. It is
structured like so:

/dev/hda3             1.4G  1.2G  213M  85% /
/dev/hda1              23M  3.4M   19M  15% /boot
/dev/hda4              17G  4.2G   13G  24% /home
/dev/hdc2              19G   16G  2.4G  87% /extra

I would like to install Redhat 7.1, but I do not want to upgrade because
for one, the root partition is I suspect too small, and two, in case I
have any problems, I would like to be able to reboot and revert to the
6.2 install on the first ide disk drive.

So I would like to install Redhat 7.1 on what is now the /extra drive. I
can blow away the existing contents of this drive without any problem. 

1) When using the Redhat install program, how do I make sure that the 7.1
installation uses only the /extra drive? I have installed Linux several
times before but have not used 7.1 and want to make sure I do not screw
this up. I want what is now the /, /boot and /home directories -- the
entire hda drive -- to remain intact.

2) How do I set up lilo.conf to offer me either of the two versions to
boot from, with the 7.1 install the default one if I do not make any
selection? Is that possible?

# /etc/lilo.conf: boot configuration

boot=/dev/hda
install=/boot/boot.b
map=/boot/map
compact
# linear

message=/boot/message
prompt
timeout=100

root=/dev/hda3
read-only

image=/boot/vmlinuz
        label=linux

image=/boot/va-linux.backup.vmlinuz
        label=backup

Any help appreciated.

Gary