I agree with Nev the answer to the first 3 is a resounding yes , now question 4 is a bit more difficult but I think you wouldn't need to take action as each os would see its assigned partition as C:/ so for example in xp you'd have your xp os as C:/ then the win 7 partition as say D:/ then your external as E:/ Data , then in win 7 it would be the reverse C:/ win 7 D:/xp , and the external as E:/ Data , as for the jumpers Nev will advise further but I personally have never bothered with them on SATA drives