installing Debian when another distro is already installed

[Guest]

Hi,
just a quick question. I need to install Debian on a computer where another Linux distro (Mandriva) is already installed. How do I avoid installing Debian to the same partitions where the other distro is alreasy installed (thus overwriting it)?
Is my guess correct, that when the partitioning tool comes up, I have to mark the Mandriva partitions as "do not use", and make new partitions for Debian?

Thanks a lot for any reply.

[ilias]

that's true but why don't you make a new partition from within mandriva...probably qtparted exists. then in the debian installer all that you have to do is choose the specific partition as root partition

[grautu]

I have to mark the Mandriva partitions as "do not use", and make new partitions for Debian?

I don't think you have to mark as Debian installer can do it for you. In fact, Debian installer offers to you the choise to install in the free space and, in case you do choose so, then you may either manually partition the free space (still being under Debian installer) or let Debian installer to partition for you. So you do not need to mark anything but just to choose.