Backing up to an external drive

Seems like this should be simple, but I want to do it right. I will be buying an external HD today to back up all of my music for itunes and all of my photos. I already have everything stored on another external HD. So, I will need to copy the contents of the drive to the new drive. Is this as simple as selecting all the highest level folders and dragging it to the new drive? When I go to backup again - say in a month. Do I just do the same procedure? Will it automatically only copy the new stuff from that month? I plan on just disconnecting the new HD and storing it someplace. Is this all good? BTW, I am using an Imac.

Stefan

If you have 10.5, then use Time Machine. Works wonderfully.

I didn't realize I could use time machine for that purpose. I am already using it for my main drive and I couldn't figure out how to make it back up an external drive.

Stefan

Unless you remove a volume (or folders or items) manually from the Time Machine System Preferences panel, it should automatically be backed up, provided you have sufficient space on your TM volume.

When I try to set up Time Machine with the new Drive, I click options. In there, I can choose drives to exclude from the backup. The drive with the photos is listed as a drive to exclude. When I click on that drive and click the minus sign, nothing happens. The drives are grayed out and they can't be removed from the list. So, I guess I can't back up an external drive using time machine. So I am back to square one with my question.

Stefan