Note you will be modifying your HD's if you mess something up here you could lose everything on all the drives that you mess with. It is therefore advised that you: Write down your current configurations. Do this by writing down all partition info (especially their sizes). Back up the partitions you are keeping. If NetBSD has to share the disk with another operating system, you must take care of partitioning your harddisk before installing NetBSD; creating space for at least root, swap and /usr partitions and possibly at least one more for /local if you have the space. Warning: The AHDI partioning function erases all partions on your harddisk even if they are not changed! I know this is rather stupid, but don't say I didn't warn you. If NetBSD has a disk of it's own, you can delay the partitioning until the installer requests you to do it.