A filesystem is out of disk space. You add a new disk. How can you use the free space on this disk without changing the current configuration?

Make a new partition on the blank disk and copy a large folder over to the blank disk (eg /usr) then edit /etc/fstab so that the new partition gets mounted. It's best if you do this from a completely separate linux install, mount your old system within the new. That way you can do brain surgery on your old system while it's unconcious.
Probably something will go wrong so make a boot disk so you can boot into either version of Linux and backup all your data before you start (maybe make a seperate "save" partition). Good luck.

humanrig,

It appears a lot of your questions come off as homework. If you take a look at our rules, it states this:

"Do not expect LQ members to do your homework - you will learn much more by doing it yourself."

I hope you respect this and you should really try to search for such obvious answers and solutions before asking for direct answers. You shouldn't rely on others to do your work for you as that will get you no where in school, life and so on..