On MacOS X I can access other drives under "/Volumes". Where do I have to go for the same under Ubuntu 9.04?
/mnt, (edit: might be
/media on Ubuntu as Moshen says) although they could be mounted anywhere in the file system.
As an aside (for those mostly familiar with MS operating systems) Unix doesn't have the concept of a drive in the way that you would see
D: on Windows. The system has a single root, which normally has the root filesystem mounted on it. Other file systems can be mounted over directories within the file system, e.g.
Traditionally removable devices such as CD-ROMs or USB drives are mounted on points that live under
/mnt but there is no reason other than convention for this.
Assuming they are mounted, they can be found under /mnt, if not, you would have to first mount the device.
If it is a hard disk or a cd-rom drive, you have to figure out which device it is, and then mount it. You could mount it anywhere you want.
mkdir /storage mount /dev/sdb1 /storage
If the volume isn't mounted typing "sudo fdisk -l" in a terminal will list all the drives and partitions that are connected to the system. Typing "mount" with no options will show you what partitions are mounted where along with some other information.
To mount an drive that's not automatically mounted you can go to "Places-->Removable Media" or "Places-->Computer" at the top and when you select an unmounted partition it should mount it for you. If that doesn't work you can type "sudo mount /dev/ /" As long as the partition is labeled properly that should work. Otherwise you may need to supply the -t option with the file system that's on the partition. Check the mount man page for more options and examples.