[solved]Synchronising Data Software

I need a kind of software, when portable HDD is plugged, it sees what all files have been updated from the last storage in the ext. HDD and copies them only
It comes with most Ext HDDs these days.
Please let me know
Answer #1
good sync
allways sync
…
Answer #2
In Vista and Win7, there is standaart a sync function
It call “offline files”
Answer #3
Thanks a ton Guys…
this is solved