seems that my macbook pro is to old for a backup server. so im looking at a Seagate Backup Plus 1 TB Portable Hard Drive. will only be backing up her computer once a week. what has always had me wondering is how these portable external HD are able to be powered by a USB. also any thoughts on the Seagate Backup Plus 1 TB Portable Hard Drive. another thought, cant i use a Ethernet cable and connect her macbook pro to my mac pro desktop and therefore backup her computer to the time machine i have on my desktop. i checked on that Yosemite server but do believe a 2006 is to old to be able to take advantage of using it, am i wrong.