I have three older computers (two P-III's, and a P-IV, all USB enabled) combined back-up under 50 Gbs. Am wondering about putting the back up soft ware on an external hard drive with three partitions, and then back up each computer to its partition. Is this doable?

Is there a better way? What software do you like?

I use and recommend Clonezilla, it does all and more than the commercial softwares...

Clonezilla