I have an older iPod that was synched to an older computer. It has about 7 G unused memory and a lot of music from the older iTunes library that does not exist anymore. There is music on one of my iTunes libraries I want to transfer to the unused space on this iPod.

Is there any way to do that without losing all the music stored on it? i.e., I want to keep what is on it, but add music files from another iTunes library.

My computer is a G4 runnng Mac OSX., The iPod in question is an 18.5 gig version 1.2.1. That's right, it is an oldie.